A User Friendly Lidar System Based on LabVIEW

Mats AnderssonFetter Weibring RgCEJV;

LRAP-201Lund, September 1996

MAR 1 7 #

DISTRIBUTION OF THiS DOCUMENT IS UNLIMITED

Department of Physics Lund Institute of Technology P.O. Box 118, S-221 00 Lund

Table of Contents

Abstract......................................................... 2

1. Introduction............................................... 31.1 Background.......................................... 31.2 Purpose................................................ 31.3 Scope................................................... 31.4 Method................................................. 3

2. The Lab VIEW Software.......................... 42.1 Background.......................................... 42.2 General Description...............................4

Construction of the front panel Construction of the block diagram Sub Vis

2.3 Data Analysis...................................... 62.4 Data Acquisition and Control................ 62.5 Instrument Control.............................. 6

3. General Description................................. 63.1 System Design..................................... 63.2 Laser Unit........................................... 83.3 Receiver Unit...................................... 83.4 Wind Unit............................................ 83.5 System Cabinet................................... 9

4. User Manual............................................ 104.1 Start-up and Shut-down Procedures.... 10

Daily Start-up Shut-down Procedures

4.2 Modes of Operation........................... 10Lidar Program Manual Control Live Curve Define Measurement Run Measurement Evaluation Presentation

4.3 Future Options.................................. 18Wind Measurement Wavelength Calibration

5. Technical Handbook................................195.1 System Design.................................... 195.2 System Computer................................. 19

Multifunction plug-in board Timing and digital I/O board GPIB interface board Local network Board

5.3 Evaluation Computer.......................... 195.4 Digitizer............................................. 215.5 Power Relay Unit............................... 215.6 Receiver Unit..................................... 215.7 Wind Unit.......................................... 265.8 Laser Unit.......................................... 265.9 Security Unit...................................... 265.10 Control Unit..................................... 29

PMT Gain Modulation Dual Delay Current Amplifier MIO-161/0 Connector Board PC-TIO-10 Connector Board

5.11 Power Unit..................................... 40Chopper Servo Motors RelaysStepper Motors

6. Software Description............................... 496.1 Lidar Program................................... 496.2 Main.................................................. 506.3 Manual Control.................................. 516.4 Live Curve......................................... 526.5 Define Measurement.......................... 536.6 Run Measurement.............................. 576.7 Evaluation......................................... 606.8 Presentation....................................... 64

7. Acknowledgements.................................. 68

8. References................................................ 68

9. Appendix................................................. 699.1 Data Analysis VI Libraries.................. 699.2 Data Acquisition for LabVIEW...........709.3 LabVIEW Instrument Drivers............. 72

AbstractMobile differential absorption lidar (DIAL) systems have been used for the last two decades. The lidar group in Lund has performed many DIAL measurements with a mobile lidar system which was first described in 1987. This report describes how that system was updated with the graphical programming language Lab VIEW in order to get a user friendly system. The software controls the lidar system and analyses measurement data. The measurement results are shown as maps of spe­cies concentration. New electronics to support the new lidar program have also been installed. The report describes how all supporting electronics and the pro­gram work. A user manual for the new program is also given.

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DISCLAIMER

Portions of this document may be illegible in electronic image products. Images are produced from the best available original document

1. Introduction1.1 BackgroundThe first Iidar measurement was performed in the 1930's. In those days searchlights were used in lidar systems for aerosol measurements in the stratosphere. This technique was used until the laser was invented. The laser turned out to be superior with regards to linewidth, output power, and pulse length. In 1963 the ruby laser came into use for lidar measurements. The main task was to study aerosols and particles. In 1966 it was possible, for the first time, to measure gas concentrations with the differ­ential absorption lidar (DIAL) technique. Today, the laser is used exclusively as the transmitter in a lidar system.

For many years researchers have tried to improve the performance of the technology. In the 1970's and in the beginning of the 1980's researchers focused on new ap­plications [1,2]. They tried to measure new species and to gather more information out of the signals received. Still, the lidar technology remained as a tool for research studies.

During the 1980's things changed dramatically. It be­came clear that man has a profound impact on the global atmosphere, land surfaces and on the bodies of water. Especially the discovery of our impact on the ozone layer has increased this awereness. All impact is due to activi­ties such as fossil fuel combustion, release of industrial chemicals into the environment and altered use of land. The demand for monitoring of the atmosphere has conse­quently increased extensively. The lidar technique is cost-efficient compared to other techniques. It is antici­pated that since the lidar systems have proven to be in­valuable in a number of environmental applications, their use will continue to increase.

The need for efficient lidar systems is obvious. Since there will be an increasing number of lidar measurements in the near future the procedure should be more auto­mated. But automation is expensive in most cases: the costs of sensors, computers, software and the program­mer's effort quickly add up. There must be ways to cut down these costs. The system should be small, light, ef­ficient, cheap, have a simple construction and be easy to use. These demands are similar to those of a customer of common radar for small boats. One must remember that in the beginning radar technology was only used by the military which has no demand for cheap and simple con­structions. Today, as a spin-off it is possible to buy small radars for only $2000. This would not have been the case if the military had not done extensive research work on radar technology. However, even if the lidar technology will go through the same development, it differs in one aspect. In the lidar case, it is necessary to save all infor­mation for presentation later on. This means that a tre­

mendous amount of data has to be analysed. Earlier, large computers were needed to do this work. Today this can be done by common PCs. The main question is how these data should be presented so that ordinary people are able to understand what it means.

1.2 PurposeThe purpose with this report is to describe how to control and run a lidar system with a software technology called Lab VIEW. This technology is based on graphical pro­gramming. The report also describes how a mobile lidar system can be upgraded with standard components to fit the new software technology. It also describes how the program analyses and presents the measurement data in a user friendly way.

1.3 ScopeThe report describes how the system is upgraded and de­scribes all details about the controlling electronics. It also describes how the Lab VIEW software works and the up­per levels in the lidar program. The software for control­ling and calibrating the laser is not presented here. That will be described in a future diploma thesis (LRAP) at the Department of Physics in Lund.

1.4 MethodAfter we reviewed the software market and systematised the different tasks required of a lidar system the final se­lection fell on LabVIEW for Windows (PC). Since we looked for a programming language which could give us a user friendly and an easy-to-understand program we fo­cused on graphical software. The choice stood between Daisylab, HP's VEE, and LabVIEW. It turned out that Daisylab, which is similar to LabVIEW, was not so dy­namic. It is more suitable for simple applications such as a lab in schools or smaller projects. HP's software is good, but it focuses to much on HP's own products. It was tough to get driver software for equipment made by other companies. However, with LabVIEW we received free software driver to almost any modem equipment controlled by GPIB, CAMAC, or serial communication.

We also wondered if the choice should be a PC, Macintosh or Unix-based platform. Since we wanted a standard and cheap solution the choice stood between PC and Macintosh. Finally, the Macintosh was excluded since PCs are more common in the industrial market and it has a more open architecture. Even in this question LabVIEW was superior. With Version 3.0 it was possible for the first time to work with LabVIEW on all three plat­forms. This means that if a LabVIEW program is devel-

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oped on a PC it can be easily switched over to, for ex­ample, a Unix work station.

When it was decided that Lab VIEW for Windows was the best choice we started to plan and construct the electronics which adapt the signals from the PC to the li- dar system. This was done in collaboration with an elec­tronic engineer at the department. The software develop­ment was done in collaboration with application engi­neers from National Instruments in Stockholm.

2. The LabVIEW Software2.1 BackgroundIn the late 1970's Jeff Kodosky started to think about a new way of programming. In those days he worked with a large test system at the Applied Research Laboratory, USA. He focused on what the program user wanted to see on the computer screen. The look on the screen should be similar to what the user sees on the actual instrument. The thought was that a virtual instrument would be com­posed of lower level virtual instruments, much like a real instrument was composed of printed circuit boards, and boards composed of integrated circuits. Later on in 1983 when he worked for National Instruments (USA) these thoughts were put into practice. It was then LabVIEW was bom.

During the 1980's the company had considerable problems with the LabVIEW development. Since this technology is based on pictures it took up a lot of mem­ory space. Macintosh was the only platform which was able to handle this properly. It was only in the 1990's that PCs were powerful enough. When Microsoft launched Windows 3.1 in 1992 LabVIEW was able to be run on a PC for the first time; see Fig. 2.1. With LabVIEW 3.0 which was launched in 1993 it was possible to run the program on all three platforms.

LabVIEW Product History

•1996-LabVIEW 4- Designed For You!- Customizable Interface

•1994-LabVIEW 3.x -LabVIEWfor HP-UX —Add-On Toolkits

•1992- New operating systems- Microsoft Windows, OpenWindows, X Windows- Introduction on other platforms

•1990 - LabVIEW 2- Four years of customer feedback -Mature product- Compiler to match Industry needs

8V LatrtflEW Concept

•1986-LabVIEW 1- Introduced Innovative approach to programming -Macintosh only possible platform

•1983-LabVIEW 1- Search for Instrumentation software solution —Virtual Instrument concept

Fig. 2.1 The LabVIEW development milestones (from National Instruments).

Another problem has been the speed of the program. In 1986 LabVIEW was still very slow. On most computa­tional benchmarks, the software was competitive with BASIC. But some applications were about 20 times slower. Today the execution speed of the program de­pends on the C-compiler only.

2.2 General DescriptionLabVIEW is a graphical programming system for data acquisition and control, data analysis and data presenta­tion. It was developed by National Instruments and offers a programming methodology in which software modules called virtual instruments (Vis) are created. With these Vis it is possible to control plug-in boards, external in­struments via serial communication, via GPIB or via VXI/VME; see Fig. 2.2. With this program the user is free to choose the components which are necessary to meet the cost and performance requirements of the appli­cation.

Computer

LabVIEW

GPIB Instruments

Plug-in Data Acquisition Boards and Signal / Conditioning (S

RS-232 Instruments VXi Instruments

Process

Fig. 2.2 The different possibilities with LabVIEW (from National Instruments).

When a system is designed, money can be saved by let­ting LabVIEW control the surrounding instruments. There is no need to buy expensive instruments with flashy user panels. It is enough that they measure what the user wants. The presentation and the analysis take place in the computer.

Construction of thefront panel With LabVIEW, pictures over the data flow are drawn instead of using written code for the program. When a program is started two different panels appear: the front panel and the block diagram; see Fig. 2.3. Each VI has these two panels. The front panel works as the user inter­face which gives the user interactive control over the software program. This panel can be filled with knobs, slides, switches, graphs, and strip charts. On this panel inputs to the program are given and the outputs from the system can be observed. Functions from a variety of

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Top-Level Front Panel

Controls Graphs

SubVI

User IconLow-Level

Front Panel

Top-Level Block Diagram

3adit Operate Functions Windows Text Help / mm

IES23Genet ales an. array conteming a sinuscttdal pattern.

sun the she and band&rited noise

Front Panel Terminal Data Flow Wire

2.3 The basic look of the Lab VIEW software

controls and indicators are selected in a palette menu. The control data type, dimension, range, default and me­chanical action can be positioned, sized, labelled and completely configured. It is also possible to import pic­tures to create new controls and indicators. The user in­terface can be designed according to user's needs. For ex­ample, if one wants to control a Multimeter, the Multime­ter VI could look the same as the actual user interface on the instrument. When the program runs, a knob can be tweaked, a slide can be moved or a switch can be clicked with the mouse. Values from the keyboard can also be given. In this manner the program is provided with in­puts. At the same time the front panel comes alive with real time feedback from the system. This information can be saved as a picture file or a hard copy is achieved by printing the front panel.

Construction of the block diagram Each symbol on the front panel has its symbol on the block diagram. This is the actual program code that is shown. Every symbol on this panel has its function writ­ten in C-code but it is shown as pictures instead of code lines. To program, VI lines are drawn between the sym­bols with the mouse. If one wants to influence a signal, functional blocks can be selected from palette menus. The different blocks are connected with wires to pass

data from one block to another. A block can be every­thing from a simple arithmetic function to an advanced acquisition and analysis routine. In LabVIEW hundreds of different functions can be chosen.

Dataflow programming is more logical to follow than the linear architecture of text based languages. The exe­cution of the different blocks is determined by the flow between the blocks and not by sequential lines of text. This means that the program does not execute a block until it receives its inputs. LabVIEW is also a multitask­ing program. It could run several Vis at the same time. Diagrams that have multiple data paths and simultaneous operations can be created.

However, even if this style of programming appears to be advantageous, one often needs to ensure a specific execution order. With LabVIEW this is done by For loops, While loops, and Case statements for sequential, repetitive, and branching operations. These structures ap­pear as graphical borders that surround the functions they control. In Fig. 2.4 an example of a While loop structure is given. The operation inside the loop takes place as long as a true condition enters the small loop symbol down to the right.

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Bigger than 0.5 ?[

Fig. 2.4 A block diagram with a While loop that contains a number of operations. After each turn the program checks and indicates if a random value is bigger than 0.5. The program runs until the stop switch control becomes false.

SubVIsIn most applications a special task has to be done several times. Sub-routines deal with these tasks in text-based languages. However, in Lab VIEW each VI can be run by itself or by another VI. If it is used by another VI it is called a SubVI. To be able to call a VI, an icon, which is a symbol of the VI, has to be created. The icon symbol is a picture and/or a name. It is shown in the upper right comer in both panels for each VI. The inputs and outputs of the VI are connected to the icon symbol with the mouse. These steps are taken on the front panel. With some help from a help window the name of the inputs and outputs are seen. This makes it easier to understand the function of a SubVI; see Fig. 2.5.

Device (1) Input Channel (0,1)

Windb!

Windmon.vi

Wind Direction Wind Speed

Fig. 2.5 An icon and its connections. This SubVI measures the wind speed and the wind direction by reading the outputs from a wind monitor. As inputs the SubVI need to know the device number of the plug-in board and what analogue to digital con­verter (ADC) it should use.

With Lab VIEW a hierarchy of Vis and SubVIs are de­signed to meet the needs. One modifies, interchanges, and combines one VI with other Vis. Each VI is tested alone and debugged. This is one of the biggest advan­tages with Lab VIEW. According to our experience a lot of time is saved in this development phase compared to text-based languages [3].

2.3 Data AnalysisLab VIEW is also a tool for doing analysis. In an analysis library more than 140 different analysis functions can be found. These libraries contain statistics, evaluations, re­

gressions, linear algebra, signal generation algorithms, time and frequency domain algorithms, window routines, and digital filters. These functions are listed in the Ap­pendix.

2.4 Data Acquisition and ControlThe main idea with a test and a measurement system is to measure different kinds of signals and to control a system with a number of outputs. This can be done in different ways. Today cheap plug-in boards have appropriate per­formance for most applications. This alternative should be considered before buying expensive instruments. Many plug-in boards do a better job and save money as well. However, one cannot expect the same performance from these boards as from an external instrument. With an external instrument higher sampling rates and better performance are expected. With a plug-in board a sam­pling rate of 100 kHz for ADCs and 100 Hz for DACs and I/Os are expected. The low frequency depends on the update speed for Lab VIEW. The DAQ VI Library has functions to control all of the plug-in boards which are sold by National Instruments; see Appendix. The library contains both simple and sophisticated functions.

2.5 Instrument ControlA test and measurement system is in most cases built up by discrete instruments, which can be controlled by GPIB, VXI, or serial communication. With LabVIEW any GPIB instrument connected to a National Instruments IEEE 488.2 interface board can be controlled. One can acquire GPIB instrument drivers, for free, from National Instruments, see Appendix. These are readable from the National Instruments FTP server or from a CD given by the company.

3. General Description3.1 System DesignA lidar system works almost like a common radar. The main difference is that a lidar system works with light pulses instead of microwave pulses. In the lidar case a pulsed laser is used as a transmitter and a photo multi­plier tube (PMT) together with a telescope are used as a receiver for the back-scattered light. The old version of the mobile lidar system has been described in detail by Edner et al [4] .The updated lidar system has four main parts: the laser unit, the receiver unit, the wind unit, and the system cabinet. All units are mounted in a Volvo F610 truck with a specially designed cargo compartment measuring 6.0 x 2.3 x 2.1 m3. The truck is equipped with supporting legs which stabilise the cabinet during meas­

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urements due to the need for high directional accuracy in the optical system. A 20 kW electrical generator mounted on a trailer provides the system with power. The system overview is given in Fig. 3.1.

Transmitting . & receiving -*l

dome I

Airconditioner

HydraulicJack

5 m

Laser bench

Telescope-

Workbench “N,

Fig, 3.1 Overview of the mobile lidar system.

As mentioned before, a lidar system has many similarities to a radar system. In a lidar system a laser unit works as the transmitter. It sends out short light pulses via a turn- able mirror mounted in the receiver unit. Stepper motors control the vertical and the horizontal direction of the outgoing beam. Due to this, spatial resolution for meas­urements in different directions can be achieved. The back-scattered light is collected by a 40 cm telescope which focuses the light on a light detector. A photomul­tiplier tube (PMT) detects the back-scattered light and gives signals, proportional to the strength of the light, to a digitizer ( analogue to digital converter). The digitizer is mounted in the system cabinet. At the same time the wind unit measures the wind speed and the direction and feeds data to the system cabinet. The system block diagram is shown in Fig. 3.2.

The system cabinet contains all computers, instru­ments, and all electronics. In the cabinet there are three computers: the system computer, the evaluation com­puter, and the dye laser computer. The system computer is the heart of the system. It contains four plug-in boards: one for data net communication, one GPIB board, and two multi-function boards, which control stepping mo­tors, servo motors, the PMT, and all electronics in the re­ceiver unit. The system computer gets inputs from the la­ser unit and the wind unit, analyses the detected signals and stores them on disc. The evaluation computer works as an instrument for evaluation and presentation of meas­ured data. The dye-laser computer controls the wave­length out from the dye laser.

1

Security Unit

3 Logic Unit

Laser Power Supply

Nd:YAG-Laser Dye-Laser Laser Output Receiver Unit

□

Power Unit

Dye-Laser Computer Evaluation Computer System Computer

Digitizer

Fig. 3.2 System block diagram.

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3.2 Laser UnitThe laser unit consists of two major parts: a Nd:YAG la­ser (YG682-20) and a dye laser (TDL60) from Contin­uum Inc., (USA). Together they work as the transmitter of the system and transmit short light pulses (6-9 ns) 20 times a second. The output energy varies from 2 -150 mJ depending on output wavelength of the dye laser. This can be adjusted manually on the laser. In order to get even shorter wavelength the output beam from the dye laser is doubled by two non-linear KDP or BBO crystals.

The Nd:YAG laser works as a main source of laser photons. Its output is powerful and stable (+/- 2.5% at the fundamental). The laser can generate laser light at the fundamental wavelength 1064 nm or its second, third or fourth harmonic (532, 355, 266 nm). The output energy is 1200, 600, 220, 80 ml, respectively. The laser also gives a trigger signal which is synchronised with the out­put pulse. For further information about this laser we re­fer to the operation and maintenance manual [5],

The dye laser is designed to be pumped by the 680- series Nd:YAG lasers from Continuum. With these de­vices the wavelength which is needed to measure differ­ent species can be produced. By using different dyes and frequency doubling, the region 200 - 1000 nm is almost completely covered. So far the most used wavelengths are: 448.03 and 446.60 nm for N02, 300.02 and 299.30 nm for S02, and 253.652 and 253.665 nm for Eg.

The laser has a special option for DIAL measure­ments, where two alternating wavelengths must be gen­erated, one for the on resonance and one for the off reso­nance. This has been solved by letting a rotating glass plate shift the intracavity beam between two tunable mir­rors in the oscillator [6]. By this action two alternating wavelengths are produced and the separation can be ad­justed manually in the laser by a knob. The laser gives a (10Hz) TTL output which tells the user if the laser transmits an on or off wavelength. Two non-linear crys­tals (KDP or BBO) are used to generate the second har­monic from the dye-laser output. Two Pellin Broca prisms are used to isolate the UV beam and the residual fundamental beam goes into a beam dump. For further information about this laser we refer to the operation and maintenance manual [7],

3.3 Receiver UnitThe receiver unit consists of a vertically mounted tele­scope with a 40 cm diameter and a flat mirror mounted in a dome, a dome camera to monitor the beam aiming, stepper motors to turn the mirror vertically, the dome horizontally, and the telescope camera horizontally; see Fig. 3.3. Thus it is possible to steer the measurement di­rection 360 degrees horizontally and within an angle of 45 degrees vertically. The mechanical construction of the dome is strong (weight of 250 kg). The movement reso­

lution is high: the horizontal resolution is 0.00353 de­grees and the vertical 0.0106 degrees.

An extra folding mirror can be installed on the roof for vertical measurements. In order to protect the flat mir­ror coating, the diameter of the outgoing beam can be made six times larger by a beam expander. Servo motors and micrometer screws are used to control the final turn­ing prism. By this arrangement the overlap between the laser beam lobe and the telescope field-of-view is con­trolled. The servo motors are controlled by LabVIEW. A mechanical chopper is used to block the outgoing beam in order to measure background light. This is later sub­tracted from the measured back-scattered light. It is also used to block the beam from unintended transmission.

Rain cover.

Stepper — motor Worm gear Flat mirror-

Quartzwindow

1^.Stepper'Y molor

Worm gear

T_ Photo- i_i—multiplier F tubeTelescope- -[)

•ConcavemirrorD = 400mm f = 1m

Fig. 3.3 Receiver unit overview [4],

3.4 Wind UnitIn order to measure a flux from a smoke stack, the total integrated concentration over the plume cross section is multiplied with the estimated wind speed around the plume. Though the lidar technique provides proper con­centration data the largest flux measurement error is to be found in the wind speed estimation. Currently, this is done by letting a wind sensor measure the wind speed 5 m above the system. Additional wind monitors at other heights are also often used. Based on measured data the estimated wind speed at the actual measuring point is cal­culated. This is a rough but easy method to estimate the wind speed for flux measurements.

The wind unit consists of a wind monitor (Young model 05305) and a wind sensor interface (Young model 05603). It is mounted on a 5m tall rod which is mounted on the truck. The wind monitor generates AC-sine wave signals with a frequency proportional to the wind speed. These are induced in a stationary coil by a six pole mag­net mounted on the propeller shaft. Three sine cycles are

8

produced for each turn. The vane position is indicated from a 10 kohm plastic potentiometer.

The sensor interface contains electronics to transform pulses into analogue signals and to generate supply volt­age for the device. The wind speed data output is an analogue signal (0-5V) or digital pulses (0.098m/s per Hz). 5V means 50m/s for the analogue output. Threshold sensitivity is 0.4m/s. The wind direction output signal is an analogue level (0-5V).

3.5 System CabinetThe system cabinet contains three computers, a digitizer and electronics to control all equipment. The three com­puters are: the system computer to control all equipment, the evaluation computer for advanced data analysis, and the dye laser computer to control the wavelength of the beam out from the dye laser. All electronics are installed in the power unit and the control unit. The front view of the system cabinet is presented in Fig. 3.4.

Dye-Laser Computer

Security Unit

Control Unit

Dye-Laser Computer

Screen and Keyboard

System Computer

Evaluation Computer

Digitizer

Power Unit

Fig. 3.4 Front view of the system cabinet

The system computer is the heart of the lidar system. It controls and runs the system via four plug-in boards, which are run by Lab VIEW. These are the AT-MIO-16 board, the PC-TIO-10 board, the GPIB board, and the lo­cal network interface board. For further information; see Chapt. 5. From the AT-MIO-16 and the PC-TIO-10 boards a number of inputs and outputs are'given: - ‘ -

• 16 ADCs with 12-bit resolution• 2 DACs with 12-bit resolution• 13 Counters or Pulse Generators with 5 MHz

clock frequency. 48 I/Os

With these inputs and outputs the computer communi­cates with the system via the control unit. Pulse genera­tors are used for controlling the vertical and the horizon­tal stepper motors. A counter is used for measuring the wind speed and the ADC inputs are used for measuring the wind direction and the dome angle. The I/Os are used for controlling the chopper and all relays. Furthermore, the I/Os are used for measuring if the laser is off or on a resonance peak. The two DACs are used for controlling the servo motors. So far we have used 12 ADCs, 2 DACs, 7 Counters, and 10 I/Os.

The evaluation computer evaluates and presents measured data. It receives data via an Ethernet board which is connected to the system computer. Thus, the measured data can be evaluated and presented in real­time by the evaluation computer. The computer screen can be updated each time a measurement cycle has been run by the system computer.

The security unit controls a chopper in the Nd:YAG laser. If the security switch is activated a chopper in the Nd:YAG local oscillator is turned on and the laser stops lasing.

The control unit takes care of all the signals from the AT-MIO-16 and the PC-TIO-10 board. It distributes the signals from the system computer to other units of the system. It has its own power supply. This unit also con­tains a high-voltage power supply for the PMT, a PMT gain modulation board for improving the dynamic range of the detector, a delay board for timing signals, and a current amplifier for measuring the background current in the PMT.

The power unit contains electronics to control stepper motors, servo motors, chopper, and relays. These boards are all controlled by the control unit. In this unit, power supplies for external use are also available.

The digitizer is controlled by the GPIB board in the system computer, which captures the signal output of the PMT with a sample rate of 100 MS/s. Normally 2000 samples, each 10 ns wide, are recorded. This corresponds to a lidar measurement range of 3 km.

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4. User Manual4.1 Start-up and Shutdown ProceduresDaily Start-up• Push the system power switch on the control unit in

the system cabinet. This will start up the system cabi­net, the dye laser, and all three computers.

• Select the Lidar Main icon in the program manager. This will load the main lidar program. Since the main program contains more than 230 Sub Vis this will take some time.

• Select the Presentation icon in the program manager. This will load the evaluation program.

• Start the Nd:YAG laser and the cooling unit by pushing the laser power switch on the control unit in the system cabinet. Use the daily start-up description in the NdrYAG laser user manual. Make sure that the cooling unit works properly.

Shutdown Procedures• Turn off the Nd:YAG laser according to the user

manual of the NdrYAG laser. Stop the NdrYAG laser and the cooling unit by pushing the laser power switch on the control unit in the system cabinet

• Stop the presentation program on the evaluation com­puter by clicking the stop switch.

• Select the Manual Control menu in the lidar program on the system computer. Click the Calibrate Dome switch and the dome will return to its starting posi­tion. Stop the main program on the control computer by clicking the stop.

• Close Windows on both computers. Wait until the DOS prompt is shown. Shut down the system power on the control unit in the system cabinet.

4.2 Modes of operation Lidar ProgramIn the lidar system, the system computer controls the measurement procedure and raw data storage. All data are sent to the evaluation computer via a local network for either real-time analysis or for evaluation and presen­tation later on. It is also possible to perform an evaluation and presentation on the system computer.

The lidar program consists of six menus, controlled by the task selection menu; see Fig. 4.1. Each menu cor­responds to a typical task that can be performed by the lidar system. A task is chosen by clicking a switch in the task selection menu. However, if the switch is shaded the task is not in function. When one uses the task menu it will always be possible to access the task selection menu to change a task.

jDe&ie Measumementjij SimMeasurementj|

; Live Curve 1

jr~.~ stop 1

Fig. 4.1 Task selection menu.

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Fig. 4.2 Manual Control menu.

Manual ControlWhen the lidar program starts the Manual Control menu appears; see Fig. 4.2. The Manual Control menu controls the dome direction, the dome cover, the detector signal selector, and the chopper. Each executed command is recorded and presented in a Log window. The Log win­dow is cleared by clicking the Clear Log switch.

When the system is started it is necessary to calibrate the dome coordinates. The dome coordinates are cali­brated by clicking the Calibrate Dome switch. This will move the dome to a starting position; 0 degrees vertically and 180 degrees horizontally (towards the back of the truck). The dome position is presented by two indicators, Vertical Position and Horizontal Position, which are placed above the dome control slides. The position is presented as degrees, minutes, and hundreds. The dome is moved in any direction by drawing the slides. Values on the slide axis indicate the frequency on which the stepper motors in the dome are running. Negative values indicates a rotation of the dome clockwise. Thus, a counter clockwise turn corresponds to an increasing value. It is also possible to move the dome by entering the new position in the digital controls below the slides and then clicking the Move Dome switch. While the dome is moving, its current position is shown on the in­dicators above the slides.

In case of rain the dome cover can be moved out by clicking the Dome Cover switch. The current position of the dome cover can be read on top of the switch.

The chopper can be controlled manually by clicking the Chopper switch.

The photo multiplier DC current is measured by clicking the DC Current Measurement switch. This will connect the PMT to the ammeter in the control unit. A 10 pA or a 50 pA range can be selected by a switch on the front panel of the control unit.

Live CurveThe Live Curve menu is used to calibrate and diagnose the lidar return signal. In this menu the Log window and the dome direction controls from the Manual Control menu are also shown.

The graph shows the lidar return signal recorded by the digitizer; see Fig. 4.3. The Y-axis is graded in counts and the X-axis is graded in meters. Each sample normally corresponds to 10 ns (100 MHz sample frequency).

Down to the left of the menu the controls for the digit­izer are found. In most cases there is an offset on the re­corded signal. This can be compensated by entering a value at the offset control. The range of the system is decided by entering the number of samples to be re­corded. In most cases 2000 samples are used, which cor­responds to a measurement range of 3 km. If the system is properly adjusted a live lidar signal can be seen on the graph. If not, check that the laser beam is emitting prop­erly and check the beam overlap.

11

Fig. 4.3 Live Curve menu.

Adjust the micrometer screws to align the beam expander and carefully fine adjust the beam direction by drawing the Overlap Adjust slides on the bottom of the Live Curve menu. This will change the angle of the final turning prism.

When the system is roughly calibrated, move the dome to an interesting measurement direction by drawing the slides that control the dome position. Each action is recorded by the log window. Open the chopper and look at the recorded signal. If the gas of intrest is present, the on and off signal should be slightly different. In Fig. 4.3 it can be seen that the recorded signal decreases with 1/R2 at long distances, but the signal is also lower at short ranges due to the gain modulation of the PMT.

The graph has a number of possibilities for studying the lidar return signal. Autoscaling, zooming, moving the cursors, changing the format, changing the precision or mapping mode of the graph, are all done with the switches placed below the graph.

When satisfied with the test, it is possible to choose another menu from the task selection menu.

Define MeasurementIn the Define Measurement menu; shown in Fig. 4.4, it is possible to define a measurement sequence and, at the same time, preliminar evaluate the recorded raw data. The defined measurement sequence can later be easily repeated from the Run Measurement menu.

In this menu the Log window and the dome direction controls from the Manual Control menu are also shown.

To the left of the menu three graphs show the data received at the current measurement direction. At the top of each graph there is a switch controlling if whether or not data should be shown. There is also a switch for the autoscaling option of the X-axis.

The upper graph shows the received signal strength recorded by the digitizer in real-time. The Y-axis is graded in counts and the X-axis in meters. As shown in Fig. 4.4, there are three different curves called "On", "Off", and "Back". They correspond to received signals for the on- and (^resonance wavelength while the "Back" corresponds to the received signal when the

12

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Fig. 4.4 Define Measurement menu.

chopper is closed which means that no laser beam is emitted. Thus, the "Back" curve shows the signal strength of background light measured by the system and can be subtracted from the recorded on- and (^wavelength sig­nals later on.

The middle graph shows the DIAL (on/off ratio) curve for the received data in real-time. The Y-axis is graded in ratio numbers and the X-axis in meters. If the curve is slightly bent with a negative derivative there is gas of interest present.

The lower graph shows the estimated concentration curve in real-time. The concentration is presented as (ig/m3 which is shown by the scale to the left of the graph. The graph also shows the standard deviation of the measured concentration, by the scale on the right hand side of the graph. The X-axis is graded in meters. Since the received signals decrease with 1/R2 the standard de­viation increases rapidly for large measurement distances.

Below the graphs there are two controls. The presen­tation Setting control decides if the graphs should be up­

dated every measured cycle (8 On shots, 8 Off, and 2 background) or when the program has finished the meas­urement direction. The On/OffTBack Source control de­cides if the presented data in the On/Off/Back graph should be signal processed due to settings in the Signal Processing menu (described later in this chapter). When defining a sweep, start by clicking the Select File switch. This opens a file dialogue window where a name of the new measurement specification file is entered. It is pos­sible to save the file in a user selected directory or in the sweep directory which is suggested by the program. Move the dome to an interesting direction and save it to the measurement specification file, by clicking the Store Direction switch. When a number of directions are saved, mark the last direction by clicking the End of Sweep switch before the Store Direction switch is clicked.

It is possible to create several sweeps in each file. Just remember that each sweep should be ended with a click on the End of Sweep switch before the Store Direction

13

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switch is clicked. When a sweep has been defined, click the Abort Definition switch. This opens a dialogue win­dow which asks if the measurement specification file is to be saved or deleted. Then the program is ready for new files or new tasks.

Before defining a measurement file a number of pa­rameters have to be set, which are devided into five groups. The parameter groups are:

• Measurement Parameters• Digitizer Settings• Temporary Digitizer Settings• Signal Processing• Evaluation Options

Only the settings in the two first groups will be saved in the measurement specification file. The remaining groups determine how to process and evaluate the real-time, data which is shown by the three graphs. All settings may be changed while the program is running. All parameters are placed in a pull-down menu, that is located to the right of the lowest graph; see Fig. 4.4. When clicking on the pull­down menu all groups will show up.

The species to be studied can be found in the Meas­urement Parameter group. The proper on wavelength will appear on the control below; see Fig. 4.5. The Type of Meas control also has to be set, by choosing between own definition, horizontal, or vertical sweep. The number of sweep repetitions and the separation between each digit­izer sample (in meters), is set by the Repetitions and Separation controls in the Measurement Parameter group.

The Digitizer Settings group controls how the digit­izer works, when it is controlled from the Run Measure­ment menu; see Fig. 4.5. The cycle value is the number of averaged cycles in every measurement direction.Each

cycle consists of 18 readings: eight on, eight off and two background readings. The sample value decides how many samples the digitizer should store for every laser shot. The offset value controls the digitizer offset input. This control is used for offset adjustments if there is an offset on the received signal.

The Temporary Digitizer Settings group has similar functions to the digitizer settings. The difference is that these settings control the digitizer temporarily when run­ning the Define Measurement menu.

The Signal Processing group consists of parameters which control raw data processing. The received signals are in most cases noisy and have to be filtered before evaluation. The result of changes in this group is seen on the On/OffrBack-graph. In the signal processing group there are five controls which give inputs to a noise filter; see Fig 4.5. With the upper control it is possible to choose between three different smoothing types: none, curve fit, or filter. The next control chooses between a Bessel or a Butterworth filter and the order of the filter. The last control makes it possible to choose the crossover point and the sample frequency of the filter.

The Evaluation Option group contains parameters which control the evaluation of the raw data and estimate the concentration curve. A free evaluation interval can be chosen by entering a start and stop sample. In Fig. 4.5 an evaluation will take place between 400 and 1050m.

This program uses three different formulas to estimate the concentration curve; sliding, integrating, or mean square error formula, all of which can be reached by clicking on the EvalFormula control. When the program calculates the concentration, it is possible to change the values of Average width and Sample width, only when using the sliding or integrating method. This is not neces­sary when the MSB formula is applied.

14

If the MSE method is used for estimating the concentra­tion, the standard deviation for the concentration curve is also calculated. This can be done in two ways, with either the exponential parametric method or the non parametric method, by clicking the Variance Me control. The Offset Sub control in this group makes it possible to subtract possible remaining DC components after back-ground subtraction.

Run MeasurementThe Run Measurement menu (see Fig. 4.6) runs a meas­urement sequence which has been defined in the Define Measurement menu.

When starting, select a desired sequence by clicking the Select File switch. This opens a dialogue window where it is possible to choose between different meas­urement specification files. A second dialogue window asks for a filename, where the raw data will be stored. A measurement is started by clicking the Start Measurement switch. While the system performs the measurement, the performance can be studied in real-time on the screen, in the same way as in the Define Measurement menu. It is possible, at any time, to abort the measurement by click­ing the Abort Measurement Switch.

The top of the menu shows which measurement specifi­cation file that controls the measurement sequence, which species are studied, the type of sweep and how many repetitions the system does for each sweep. Meanwhile, the log window presents each action. In the middle of the screen the current dome position is shown by two indica­tors. ‘ . - ..

To the left three graphs show the result of a measure­ment. They have the same function as in the Define Measurement menu. Below the graphs the Presentation Setting control and the On/OffTBack Source selector are placed. In the pull-down menu two parameter groups are found; the Signal Processing and Evaluation Options. They have the same function as in the Define Measure­ment menu. However, these settings will not be saved in the raw data file. They only influence the result shown on the three graphs.

Below the task selection menu the digitizer settings are shown. These settings are read from the Measurement specification file. The upper indicator shows how many cycles the digitizer runs for each direction. The following indicators show the number of samples, the offset value, and the number of sweep repetitions left to run.

When the system has finished a measurement, a dia­logue window appears on the screen asking if the raw data file is to be saved or deleted. Now the system is ready for a new task.

Fig. 4.6 Run Measurement menu.

15

EvaluationThe Evaluation menu evaluates raw data files and creates evaluated measurement files; see Fig 4.7.

Directions can be evaluated separately or all together with the same evaluation parameters. When starting the evaluation, choose a raw data file by clicking the Select RawDataFile switch. The remaining switches are shaded and disabled until a raw data file has been chosen.

When a raw data file is loaded the program shows the evaluated data for one direction on three graphs in the same way as in the Define Measurement menu. They show the on/off/Back curve, the DIAL curve, the concen­tration curve, and the standard deviation curve for one direction. Meanwhile, on top of the menu, the program gives information about the name of the source file, which species have been measured, what wavelength was used, type of sweep, and how many repetitions the sys­tem has done for each direction.Down to the right three switches are placed: Go Forward, Re Evaluate, and Go Backward. If the Go Forward switch is clicked the program continues to the next direction in the raw data file. If the Go Backward switch is clicked the program goes to the previous measurement direction. The Re Evaluate switch is used to re-evaluate the present direction, when changes have been done in the parameter setting groups.

For every direction, Signal Processing settings and Evaluation Options settings can be changed; see Fig. 4.5. Either one of the parameter setting groups can be chosen

by clicking on the pull-down menu below the direction indicators. Within the Signal Processing settings it is possible to decide how the raw data will be filtered. How the concentration curve will be calculated is decided within the Evaluation Options settings group, as de­scribed earlier. For each measurement direction the verti­cal and the horizontal direction are displayed on the menu to the left of the three switches. When the program reaches the beginning or the end of a raw data file, this is indicated by the program, and a beginning of file or end of file is written above the direction indicators.

When satisfied with the evaluation of one direction the result is saved by clicking the Store Direction switch. This has to be repeated until the desired directions have been saved. It is not necessary to save all directions. If all directions are to use the same parameter settings the Store All Direction switch can be used. This will cause the pro­gram to evaluate and store all remaining directions in the evaluated data file according to the current parameter settings. If only the raw data for higher directions are to be evaluated, the minimum vertical direction on the Limit control can be found above the dome position indicators.

Finally, when the program is finished with a raw data file, click the Abort Create Eval File switch. A dialogue window will then appear on the screen with the choice of saving or deleting the evaluated data file. The program is now back to its starting position and ready for new tasks.

i

Fig. 4.7 Evaluation menu.

16

PresentationThe Presentation menu reads evaluated data files and presents the result as concentration maps on the computer screen; see Fig. 4.8. The Presentation program can also read evaluated temporary files from the Run Measure­ment program in the system computer. This allows real time display of the measurement situation.

A concentration map can be made by clicking the Select New File switch to the right on the menu. The program opens a dialogue window asking for the name of the desired evaluated data file. In the middle of the menu a large graph is placed where the concentration map is shown. The X-axis and the Y-axis are graded in meters. The concentration scale is located to the left of the graph. A dark colour indicates a lower concentration. Below and beside the graph two diagrams are placed. On these dia­grams the vertical and the horizontal integration of the concentration map are shown. Below each diagram the centre of gravity for the concentration distribution is shown.

To look at the result of the next sweep click the Go Forward a Sweep switch, and to look at the previous sweep click the Go Backward a Sweep switch. The Sweep Nr indicator shows the number of the current sweep. On the top of the menu six indicators show which

source file the program uses, which species the program has measured, which wavelength has been used, type of sweep, and which methods have been used to evaluate the raw data.

To the left of the menu there is a column of eight in­dicators. The first two indicators ArealntConc and Std C present the area integrated total concentration (g/m) and its standard deviation. The next four indicators show the measured wind speed, wind direction, and standard de­viations for these values. The last two indicators show the estimated flux (g/s) and its standard deviation. The flux is calculated by multiplying the integrated concentration with the perpendicular wind speed.

Down to the left of the menu, controls for deciding the source of wind speed and wind direction are placed. For the wind speed estimation it is possible to choose between three sensors; a wind monitor mounted on the truck, a CCD camera, or inputs from the keyboard. For the wind direction it is possible to choose between three sensors: a wind direction monitor mounted on the truck, laser distance measurement, or inputs from the keyboard. The last four controls are keyboard inputs for wind di­rection, wind speed, and their standard deviations.

Fig. 4.8 Presentation menu.

17

Below the header Evaluation, there are three switches. The Recalc parameter switch has to be used to recalculate all values, when there has been any alterations in the Wind option parameters. The Calculate variance switch activates and deactivates the variance calculation process. Finally, the Auto Map Sweep switch is used to present measurements in real time.

Below the header Average Sweep, there are switches for creating an average sweep by going through a number of sweeps. Just click the Add Sweep to the Average switch each time a sweep is to be added. With the Clear Average switch the averaged sweep is deleted.

Below header Show options, there are pull-down menus to control the graphs. In the upper pull-down menu it is possible to choose whether the graphs will show a single sweep or the average sweep. In the lower pull-down menu it is possible to decide if the graph will show raw concentration, smoothed concentration, raw variance, or smoothed variance.

4.3 Future Options and DevelopmentWind MeasurementIn Chapt. 3.4 it was mentioned that the wind speed esti­mation currently has large errors. The reason is that a wind monitor which is mounted only 5 m above the sys­tem was used. However, the smoke stack can" in many cases be more than 100 m above the system and several hundred meters away. Therefore, additional wind moni

tors at other heights are sometimes used, if they are avail­able. It has turned out during the years that the wind measurement affects the flux estimation the most. The estimated concentration accuracy is about 10% while the measured wind speed accuracy at the measurement di­rection can be much worse than this.

In order to improve the wind speed estimation a video graphical technology can be used [8], The idea is based on the technique that a frame grabber is repeatedly used to grab pictures of the plume and look at the plume movement between two pictures. The new wind speed sensor will be included in the near future.

Wavelength CalibrationWavelength calibration of the laser output is critical for most lidar systems. Especially if species with narrow linewidth like mercury are measured, the laser must be calibrated several times every hour.

In order to make sure that the laser wavelength is calibrated a calibration unit is under construction. The project will be described in a Diploma thesis [9]. The project includes both software development and hardware construction. The idea is to let the system computer con­trol a number of gas cells and to measure a small part of the laser light which passes through the appropriate cell. Simultaneously, the dye laser wavelength is scanned until the transmitted light is minimised. The dye laser will be controlled by the system computer and it will be possible to do the calibration manually or automatically by the lidar program.

18

5. Technical Handbook5.1 System DesignThe lidar system consists of four major parts: a system cabinet, a laser unit, a wind unit, and a receiver unit. The system cabinet runs on a 230 VAC (one phase) and feeds the wind unit and the receiver unit with power. The laser unit runs on a 230 VAC (one phase) and is cooled by a cooling machine which is mounted under the floor of the truck. The cable connection between the different parts is shown in Fig. 5.1, the system block diagram.

5.2 System ComputerAn IBM-compatible PC, Pentium with a 133 MHz processor is used as a system computer. This computer controls all electronics and runs the system. It has a 500 Mbyte disc, 70 MBytes of RAM, 4 PCI slots, 3 EISA slots, and a 14 inch screen. It contains three plug-in boards with ISA slots and one plug-in board with a PCI slot. The multi-function input/output board (AT-MIO- 16DL) is used to read analogue and digital inputs and to generate analogue and digital outputs. The timing input/output board (PC-TIO-10) is used to generate and count pulses in order to control all stepper motors. The GPIB hardware board (AT-GPIB) communicates with the digitizer, and the local network interface board is used for communication with the evaluation computer. The computer runs on Windows 3.11 and with Lab VIEW for Windows 3.1.1.

Multi function plug-in boardThe AT-MIO-16DL board from National Instruments is a high-performance, multifunction analogue, digital, and timing I/O board for the IBM PC AT. It has 100 inputs/outputs which are connected to two connector boards of 50 connector pins each. These are called the MIO-161/O connector (1-50) and the DIO-241/0 connector (51-100). The board contains a 12-bit ADC with up to 16 analogue inputs, a maximum sampling rate of 100 kS/s, two 12-bit DACs with voltage outputs, 32 lines of TTL-compatible digital inputs and outputs, and three 16-bit counter/timer channels for timing input and output. The clock frequency of these counters are maximum 1 or 5 MHz. The ADC inputs can be run as 16 single ended inputs or as 8 differential inputs. This board also has a voltage source of 5 V with a maximum current of 1A. For further information about this device we refer to the AT-MIO-16 user manual [10].

Timing and digital I/O boardThe PC-TIO-10 board from National Instruments is a timing and digital I/O board for the IBM PC/XT/AT and compatibles. It has 50 inputs/outputs which are connected to a connector board of 50 connector pins. The board has 10 channels of 16-bit counters/timers with a 1 or a 5 MHz source, and 16 channels of TTL-compatible digital I/Os. The plug-in board has a voltage source of 5 V with a maximum current of 1A. The counter/timer channels have many timing and counting modes, including event counting, pulse generation, and frequency measurement. The counters/timers are controlled by software, level gating, or edge gating. For further information see the PC-TIO-10 user manual [11].

GPIB interface boardThe AT-GPIB board (Rev E2) from National Instruments is a full-function IEEE 488 interface for the IBM PC/XT/AT bus equipped with 16-bits ISA slots. This board is used to control and to receive measurement data from the digitizer. The AT-GPIB board performs the basic IEEE 488 Talker, Listener, and Controller functions required by the most recent GPIB standard, IEEE 488.2. For further information see the AT-GPIB (Rev E2) user manual [12].

Local network boardThe EtherLink III board from 3Com belongs to the third- generation of Ethernet adapter boards. This family includes the 32-bit bus master Peripheral Component Interconnect (PCI) 10 Mbps Ethernet network adapter, which conforms to the PCI 2.1 specification. The system computer uses this network board for data exchange with other computers. The board is also used for transferring measurement data to the evaluation computer. For further information refer to the user manual [13].

5.3 Evaluation ComputerA PC 486 DX2 with a 66 MHz processor and 32 MByte RAM is used for evaluation and presentation of lidar data. This computer has a Windows 3.11 platform and runs LabVIEW 3.1.1. It communicates with the system computer via the local network. The evaluation computer uses the same kind of network board as the system computer.

19

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5.4 DigitizerThe digitizer is a 100 MHz, 8-bit, two channel digitizer from LeCroy. It is based on modular design with the CAMAC communication language. The digitizer is built up by a CAMAC module house 8103 which contains power supply and housing, two waveform digitizers TR8818 with two supporting memories MM 8103A, and a GPIB to CAMAC interface 8901 which controls the digitizer. More information about this product can be found in the user manual of the digitizer [14].

5.5 Power Relay UnitThe power relay unit contains relays to control the electric power of the system; see Fig. 5.2 and 5.3. All relays are mounted in a box except the high-power relay (relay 5). This relay is used for feeding the Nd:YAG laser and the cooling machine with 230 VAC. The high-power relay is controlled by the laser power switch on the front panel of the control unit.

Fig. 5.2 Front view of the Power Relay Unit.

Relay 1 and 2 connect the electrical power to the system cabinet. This is controlled by the system power switch on the front panel of the control unit. Relay 3 connects the electrical power to a heating fan in the receiver unit. Relay 3 is controlled by an I/O output from the system computer. Relay 4 is part of a security loop which is further described in Chapt. 5.9.

5.6 Receiver UnitThe receiver unit is connected to the system cabinet by seven cables; see Fig. 5.4 to 5.6. Starting with Fig. 5.4 a cable is wired from the power unit plug J9 via a connection box C3 and a 15-pin cable plug J1 to the chopper and the servo motors. In this cable position feedback signals, chopper control signals, and servo motor signals run.

The mechanical chopper controls the laser output from the system. Its function is based on two electro magnets which pull or push a mechanical chopper. Thus, the laser beam can be prevented from leaving the system. The electronics for controlling the magnets are mounted in the power unit in the system cabinet.

Two servo motors tilt a prism in the receiver unit vertically and horizontally in order to control the direction of the emitted beam. Two potentiometers indicate the position by a voltage proportional to the position.

A heating fan which removes moisture from the dome - window is mounted close to the dome mirror. Further, a cable wired from the power relay unit provides the fan with power. The cable is wired from the fan, via a three pin cable plug J2, to relay 2 in the power relay unit; see Fig. 5.4.

In Fig. 5.5 a cable is wired from the connector J10, mounted in the power unit, via a 14-pin MS-E cable plug J3 in the receiver unit, to a connection box C5 in the dome. In this cable vertical stepper motor signals, a dome cover control signal and a vertical position feeedback signal run.

A potentiometer mounted in the dome generates a voltage proportional to the vertical angle. However, this signal generates only rough information. An opto interrupter mounted in the dome generates a signal when the dome mirror has a 45 degree position (corresponds to a zero degree output beam angle). This sensor is used for calibration of the vertical position of the mirror.

The dome cover works as a protector for intensive sunlight and for rain. The cover is moved over the quartz window in case of rain by an electrical motor on 12 VDC. The motor direction is controlled by relay 2 on the relay board mounted in the power unit. The control signal is transferred via the 14-pin MS-E cable plug J3 and the connection box C5 to a relay mounted close to the dome cover motor in the dome. The end positions for the dome cover are detected by two switches; see Fig. 5.5.

The 14-pin MS-E cable plug J3 also contains a coax cable which is wired from the dome monitor to the dome camera mounted in the dome front. In this cable the signals generated by the dome camera run. The dome monitor is mounted close to the workbench.

In Fig. 5.6 a cable is wired from the cable plug J11 in the power unit to the horizontal stepper motor and to the telescope camera stepper motor via a connection box Cl. In this cable stepper motor signals run. The horizontal stepper motor turns the dome via a worm gear. The telescope camera motor is used for turning the camera so a correct image can be seen on the telescope monitor.

A second cable is wired from the cable plug J15 in the control unit via connection boxes C2 and C4 to a feedback potentiometer and to an opto interrupter. In this cable horizontal position feedback signals run. These sensors have a similar function to the vertical position sensors. Fig. 5.6 also shows the wiring from the detector (PMT) to the digitizer and the control unit.

21

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5.7 Wind UnitThe wind unit is wired to the control unit via a six-pin cable plug; see Fig. 5.9. The cable is wired from the system cabinet through the front wall of the cargo to the wind sensor interface. The six-pin cable plug is placed under the truck close to the rod on which the wind sensor is mounted [15,16],

5.8 Laser UnitThe laser unit consists of the Nd:YAG laser, the dye laser, and the dye pumps. The Nd:YAG laser runs on one phase 230 VAC while the dye laser and the dye laser pumps run on 115 VAC; see Fig. 5.7.

Nd:YAG Laser Dye Laser

Laser Power Supply

Fig. 5.7 The laser unit.

5.9 Security UnitThe security unit controls the laser output from the Nd:YAG laser (the front and rear panel of the unit are shown in Fig. 5.8). The security loop is fed by an internal power supply of 24 VDC; see Fig. 5.10. It runs through the security button switch, the system power relay 1, and the security key on the front panel. When the system is powered up the loop is closed by turning the security key. Thus, the security relay is activated by a by-pass line and a green light on the front panel lights up. This action also activates the relay 4 in the power relay unit.

Relay 4 is part of a line which controls a mechanical chopper mounted in the local oscillator of the Nd:YAG laser. As long as the mechanical chopper is activated laser beams are generated. When Relay 4 is deactivated the mechanical chopper loses its power and blocks the laser beam.

If the security button is pushed the security relay and relay 4 will be deactivated and the Nd:YAG laser stops running. Meanwhile, a red light on the front panel appears. The security relay can be reactivated by resetting the security button and by turning the security key. Thus the by-line loop will be closed again.

jt (COMMON GROUND)

42 (220 VAC)

Fig. 5.8 Front and rear panel of the security unit.

26

WIND UNIT

WIND UNITSENSOR INTERFACE CIRCUIT

CONTROL UNIT

CABLE SHIELDCABLE SHIELD + 12V

AZIMUTH VOLTAGE VINO SPEED VOLTAGE

VINO SPEED PULSES GROUND

VINO UNIT

LUND INSTITUTE OF TECHNOLOGYDEPT. OF PHYSICSBOX 118221 00 LUND

W'UNIT

“vVnoI'sch “h'V ""'"'TrduRE 5.9 "T""bV / 0 3/ 9 G*! M A "'09/06/96 SHEET 1 OF 1

SECURITY UNIT

SYSTEMROVER

ROVER RELAY UNIT

SECURITY UNITLUND INSTITUTE OF TECHNOLOGYDEPT. OF PHYSICSBOX 118221 00 LUND

stmt minSECURITY UNIT

ShSECUR,|TY.SCH S'fU C°CU"*t “fVgURE 5.10 'T

*03/12/96"MR *09/06/96 SHEET 1 OF 1

5.10 Control UnitThe control unit contains a high-voltage power supply, a PMT gain modulation power supply, a PMT gain modulation board, a dual delay board, a current amplifier, and a power supply. The control unit also contains the system power switch and the laser power switch and three connection boards for connecting signals to the AT- MIO-16DL and the PC-TIO-10 plug-in board; see Fig. 5.11-5.13.

SYSTEM LASER POWER POWER

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Connector Board

DIO-24 I/O

PC-TIO-10

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information refer to the operation and service manual of the Highpac power supply [17].

Normally, the PMT voltage level is -2300V. The PMT DC current can be measured by activating relay 4 on the relay board mounted in the power unit; see Fig. 5.26. By this action the detector signal runs through the power unit and reaches the detector current cable plug J9; see Fig. 5.12. After amplification by the current amplifier board, the detector current is measured and presented on the front panel by an ammeter. Range values of 10 or 50 gA can be chosen. To decrease the DC-current value, the input voltage to the PMT can be decreased or an extra filter in front of the PMT can be added to decrease the amount of incoming background light.

The PMT gain mod. connection J6 contains a signal, generated by the dual delay board, which modulates the PMT.

The Nd:YAG laser gives short trigger pulses 20 times a second which trigger the PMT gain modulation board and the dual delay board. The laser trigger enters the control unit at the laser trigger input J7; see Fig. 5.12. The dual delay board generates two delayed signals for synchronisation. The cal. unit trigger output J11 will be used to trigger the laser calibration unit (under development) [9]. The digitizer trigger output signal J10 is used to trigger the digitizer.

In Fig. 5.13 three connector boards which connect the At-MIO-16DL and the PC-TIO-10 plug-in boards with the system are shown. The angle sensors, the wind unit, and the power unit connectors are wired to the MIO-16 connector board. These connections are further described in the MI0-16I70 connector block diagram; see Fig. 5.19. Currently, the DI0-24I/0 connection board is not used. The TIO-10 board is connected to the angle sensors, the power unit, and the wavelength on/off connection. The wavelength on!off signal is a 10 Hz square wave from the Nd:YAG laser which tells the system if the laser emits on or off resonance line. For a further description of these connections refer to the MIO- 16- and the TIO-10 connector board diagram; see Fig. 5.19-5.20.

Fig. 5.11 Mounting overview and the look of the front and rear panel of the control unit.

Starting with Fig. 5.12 when the system power switch is pushed all internal power supplies are powered up. The internal power supplies generate: +5V, +12V, -12VDC, and a tuneable high voltage. The high voltage power supply (Highpac) is a high-voltage, high stability, low ripple, regulated DC power supply. The output level is controlled manually on the front panel (a remote controlled version is under development). The Highpac device feeds the PMT via the PMT-HV connection J5 with a negative voltage; see Fig. 5.11-5.12. For further

29 \

CONTROL UNITLUND INSTITUTE OF TECHNOLOGYDEPT. OF PHYSICSBOX 118221 00 LUND

Stint Title:CONTROL UNIT

“'c'oNTROLl.SCH s.„, “-'FrdURE 5.13 *T“aa/'ia/a'e'hfl "09/0G/9G SHEET 2 OF 2

PMT Gain ModulationDue to the fact that the back-scattered light intensity is proportional to 1/R2, the dynamic range of the incoming back-scattered light is large. In order to increase the dynamic range of the detected signal, the PMT is modulated with a voltage ramp to make the detector less sensitive for back-scattered light at short distances [18]. The technique is based on the modulation of the dynode voltage in the PMT. The modulation signal is created by the PMT gain modulation board; see Fig. 5.15. The PMT gain modulation power supply board is shown in Fig. 5.16.

The laser trigger enters the PMT gain modulation board at pin 1. It triggers a monostable multivibrator whose pulse length depends on the RC constant for the 100 pF and the 10 k£2 potentiometer. With a potentiometer the pulse length is set; see point A in Fig. 5.14-5.15. Since the second multivibrator is triggered on a negative flank, the pulse length of the first multivibrator delays the created pulse compared to the trigger input; see point B. This option compensates for the time it will take for the laser pulse to go back and forth from the minimum measurement distance is.

After the second multivibrator the pulse enters a block which creates a slope in the beginning of the pulse. However, the total pulse length will not be changed. As long as there is no pulse that enters the block, the constant current generator in the block is fed by the transistor above the two diodes; see point C. When a pulse enters the board, the transistor is shut down and the constant current generator starts to charge up the 15 nF capacitor. This produces a constant increase of voltage over the capacitor that will bias the last transistor in the block. Out from the block an inverted pulse with a slope in the beginning of the pulse is given. The slope angle depends on how fast the constant current generator charges up the capacitor. The constant current value can be set by the slope adjust potentiometer; see Fig. 5.15. The last block amplifies the pulse and makes it negative; see point D.

Trigger___j______________________________

A

Time -----------------------------------------------►

Figure 5.14 The development of the PMT gain modulation pulse

Dual DelayThe dual delay board delays the trigger signal for two purposes. First, the digitizer trigger has to be delayed due to improper performance of the digitizer. Second, the read out of the calibration unit has to be delayed due to synchronisation between the laser trigger and the signals from the light detectors in the calibration unit. In Fig. 5.17 the dual delay board diagram is shown. All circuits are monostable multivibrators.

In the lower section of the figure a calibration trigger delay is generated. The trigger input starts the circuit and the pulse is extended from the first multivibrator depending on the time constant of the 50 kO potentiometer and the 150 nF capacitor. Since the second multivibrator triggers on the negative slope, the pulse length from the first multivibrator sets the delay. The second circuit decides the pulse length from the board.

In the upper section of the figure a trigger delay to the digitizer is generated. The method to generate a delayed pulse is similar to the calibration trigger delay. However, there is a possibility to add an extra delay by setting the extra delay control high. By this action a relay is activated which adds an extra resistance in the time constant circuit. This option is used when the digitizer runs with 50 MHz instead of 100 MHz. Thus, the measurement range increases from 3 to 6 km.

Current AmplifierThe PMT gives a small DC current (pA) depending on the amount of back-scattered light and the interfering filter used. If the background current is too large the PMT can be damaged. The current amplifier board increases the sensitivity of the ammeter. The board input is connected to a 50 O load. After amplification the current value is shown on an ammeter on the front panel; see Fig. 5.18. With a range selector switch on the front panel the range can be chosen between 10 pA or 50 pA range.

AT-MI0-16I/0 Connector Board The MIO-161/0 connector board has 50-pins which contain signals with the MIO-16 circuitry. The connector contains a 12-bit ADC with 16 analogue inputs, two 12- bit DACs with voltage outputs and eight lines of TTL compatible digital I/O interface based on a 82C55A programmable peripheral interface (PPI).

The analogue inputs are configured with differential inputs (eight inputs) and with a -10V to +10V input range. These inputs are used to measure the wind speed, wind azimuth angle, the vertical and horizontal angle of the dome; see Fig. 5.19. However, all signals are measured compared to ground.

32

The two analogue outputs (DACs) control the servo motors in the receiver unit. They have a bipolar output (- 10V to 10V) according to the factory setting of the plug­in board.

Eight I/O lines are grouped in two ports (A and B) with four lines each. Both port A and B are used as digital outputs. Lines 1-4 in port A are used for controlling the chopper, relay 1 (not used), the dome cover, and the heating fan. Lines 1 and 2 in port B are for controlling the detector signal measurement and the extra delay of 20 gs on the delay board.

PC-TIO-10 Connector BoardThe PC-TIO-10 connector board has 50-pins which contain many different timing and counting modes. The board performs pulse measurements and wave generation functions. Furthermore, the PC-TIO-10 board has a digital VO interface with two 8-bit I/O ports (A and B), which are bit-configurable.

Six counters are used for creating pulses and counting pulses to control the stepper motors. Counter 1 and 2 make pulses (0-1000 Hz) for the horizontal and the camera stepper motor; see Fig. 5.20. Counter 3 and 4 are used for counting the generated pulses. From these counters the system program knows how many steps the dome has been moved horizontally: Counter 5 is used’for creating pulses (0-400 Hz) for the vertical stepper motor. These steps are counted by counter 6. Counter 7 to 10 are not used.

Port A is configured as an input. Three out of eight inputs are used for measuring digital inputs such as the wavelength on/off, horizontal reference, and vertical reference signal. Port B is configured as an output. Three of these outputs are used for controlling the direction of the stepper motors.

33

PUT GAIN MODULATION

DELAY

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0 PRE-OUTPUT LEVEL 0C54-7

BC54-7

0BIAS LEVEL

OUTPUT LEVEL

PUT GAIN MOO

COMMON GROUND LUND INSTITUTE OF TECHNOLOGY DEPT. OF PHYSICS BOX 118 221 00 LUND

THIS PART BELONGS TO THE CONTROL UNITLASER TRIGGER

PUT GAIN MOD CONNECTOR Hint Tltlil

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220V AC

PUT GAIN MOD . POWER SUPPLY

0 HEAT SINK

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THIS PARTBELONGS TOTHE CONTROL UNIT

LUND INSTITUTE OF TECHNOLOGYDEPT. OF PHYSICSBOX 118221 00 LUND

stmt minPUT GAIN MOO. POWER SUPPLY

$hR2P0UER. SCH $lfH D°6”“t "f'VgURE 5.16 *T

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0 DELAY ADJUST 0 - 25us

0 DELAY ADJUST 0 - Sms

DUAL DELAYTHIS PARTBELONGS TOTHE CONTROL UNIT

LUND INSTITUTE OF TECHNOLOGYOEPT. OF PHYSICSBOX 118221 00 LUND

amt minDUAL DELAY

^OELHY'.'SCH Sm ,M,U,,,mURE 5.17

**0 3^ 11 / 9 B** M R l,09/06/3,6 SHEET 1 OF 1

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MICRO- TO M ILL I AMPS CONVERTORDETECTOR CURRENT NEHSURENENTS

+12V RED

REAR PANEL OF THE CONTROL UNIT

FRONT PANEL OF THE CONTROL UNITOFF-SETDETECTOR

CURRENT

RANGE SELECTOR

FRONT PANEL OF THE CONTROL UNIT

SM'loTHE CONTROL UNIT

LUND INSTITUTE OF TECHNOLOGYDEPT. OF PHYSICSBOX 118221 00 LUND

shut minCURRENT AMPLIFIER

"m'icroamp.sch "bv ,m,e,,rrduRE 5.i8 - it

Sk03/“2/9Ge‘t1A "09/06/96 SHEET 1 OF 1

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WIND SPEED VOLTAGE AZIMUTH VOLTAGE

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DET. SIGNAL SELECT HEATING FAN GROUND

HEATING FAN CONTROL DOME COVER GROUND

DOME COVER CONTROL RELAY 1 GROUND

RELAY 1 CONTROL VERTICAL REFERENCE

VERTICAL ANGLE MOTOR GROUND

VERT. DIR. CONTROL CAM. DIR. CONTROL HOR. DIR. CONTROL

VERT. MOTOR CONTROL CAM. MOTOR CONTROL HOR. MOTOR CONTROL VERT. SERVO GROUND

VERT. SERVO CONTROL HOR. SERVO GROUND

HOR. SERVO CONTROL CHOPPER GROUND

CHOPPER CONTROL CABLE SHIELD

ROVER UNITJ15

CABLE SHIELD COMMON GROUND

HORIZONTAL ANGLE + 12V

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FLAT CABLE CONNECTOR Ml 0-16 I/O

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THIS PARTBELONGS TOTHE CONTROL UNIT

LUND INSTITUTE OF TECHNOLOGYDEPT. OF PHYSICSBOX 118221 00 LUND

s>«t mi«iMIO-lGi/O CONNECTOR BOARD

^n'lO-HLSCH % "TfduRE 5.19 eT

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HEATING FAN CONTROL DOME COVER GROUND

DOME COVER CONTROL RELAY 1 GROUND

RELAY 1 CONTROL VERTICAL REFERENCE

VERTICAL ANGLE MOTOR GROUND

VERT. DIR. CONTROL CAM. DIR.HOR. DIR.

VERT.CAM.HOR. MOTOR CONTROL VERT. SERVO GROUND

VERT. SERVO CONTROL HOR. SERVO GROUND

HOR. SERVO CONTROL CHOPPER GROUND

CHOPPER CONTROL CABLE SHIELD

CONTROL CONTROL

MOTOR CONTROL MOTOR CONTROL

ROVER UNIT

WAVELENGTHON/OFF

CABLE SHIELD COMMON GROUND

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50-POL)

FLAT CABLE (50-POL)

6NO

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THIS PARTBELONGS TOTHE CONTROL UNIT

LUND INSTITUTE OF TECHNOLOGYDEPT. OF PHYSICSBOX 118221 00 LUND

nut minPC-TIO-10 CONNECTOR BOARD

WfiVsCH S'fH "nGURE 5.20 *T

Sh03/20/9Ge,MA "'09/06/96 SHEET 1 OF 1

5.11 Power UnitThe power unit consists of a number of blocks: stepper motor drivers, stepper motor power supply, relay control, servo motor control, chopper control, and a power supply; see Fig. 5.21-5.23. Starting with Fig. 5.22 the power unit is activated when the system power switch is pushed. The internal power supply feeds the unit with +5V, +12V, +24V, -12V, and -24VDC. Fig. 5.23 shows how the detector signal input from the PMT is connected to the detector current connection or the detector signal output. If the relay is not activated the signal enters the detector signal output connector and continues to the digitizer. Otherwise the detector signal will enter the ammeter in the control unit.

O <s)<2)©<S)

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Rear Panel

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Horizontal Motors (J11)

Fig. 5.21 Mounting overview and the front and rear panel of the power unit.

ChopperA push-pull circuit, which is controlled by the chopper control signal, controls the chopper mounted in the receiver unit; see Fig. 5.24. Each of the transistors on the board are connected to a electro magnet which pulls the mechanical chopper. The control signal is generated by the system computer.

Servo MotorsThe servo motors are controlled by two regulators; see Fig. 5.25. The sensitivity of the loop gain can be set by the 470 k£2 potentiometer placed on the board. Each axis of the servo motor is connected to a potentiometer that generates feedback voltage to the servo motor board. The feedback voltage is compared with the 12-bit analogue control signal level from the MIO-16 board. Thus, the position of the servo motors is controlled by the system computer.

RelaysThe relay board is built to supply four devices with 24V differentially; see Fig 5.26. It has four identical relay blocks which can be controlled by TTL signals from plug-in boards. These relays are used to control a heating fan in the dome, to control the dome cover motor, and to control the high-frequency relay which decides whether the detector signal should be connected to the digitizer or the ammeter.

Stepper MotorsAll four stepper motor drivers are mounted on one board; see Fig. 5.27 and 5.28. All drivers have their own power supply mounted in the power unit; see Fig. 5.29. Currently, three integrated circuits (GS-D200S) are used as drivers (the fourth is not used). Each stepper motor driver board has two inputs, step and direction and four outputs. Each input runs via a transistor amplifier to the driver circuit. These transistors protect the plug-in boards from short circuits.

40

COMMON®GROUND

SYSTEM POWER

BLK

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POWER UNIT BLOCK------------------------------- ------------------------------------------

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MOTOR GROUND VERT. DIR. CONTROL

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LUND INSTITUTE OF TECHNOLOGYDEPT. OF PHYSICSBOX 118221 00 LUND

skiit mi«iPOWER UNIT

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LUND INSTITUTE OF TECHNOLOGYDEPT. OF PHYSICSBOX 118221 00 LUND

Shut TitlePOWER UNIT

sTouerT.’sch '""""FIGURE 5.23

"03/"3/96":A "09/06/36 SHEET 2 OF 2

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LUND INSTITUTE OF TECHNOLOGYDEPT. OF PHYSICSBOX 118221 00 LUND

stmt mmCHOPPER CONTROL

“"HOPPER.SCH $lfU * FIGURE 5.24 *T

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0 HEAT SINK

THIS PARTBELONGS TOTHE POWER UNIT

LUND INSTITUTE OF TECHNOLOGYDEPT. OF PHYSICSBOX 118221 00 LUND

skut minSERVO MOTOR CONTROL

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LUND INSTITUTE OF TECHNOLOGYDEPT. OF PHYSICSBOX 118221 00 LUND

Shut Till*:BOARD OF RELAYS

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6. Software Description6.1 Lidar ProgramIn Lab VIEW lines and symbols are drawn instead of writing code. Each symbol or SubVI represents a special task which has many similarities with common sub­routines in a text based programming language. Instead of creating a header in each subroutine with global and local variables, lines are drawn between the symbols. Data run through the lines and the SubVI's do not execute until they have received all data for their inputs. The thickness and the colour of the line tells you what kind of data it contains.

LabVIEW is from the beginning designed to work without global variables since all information is wired between the Sub Vis. However, this has later proved to be inconvenient and it is now possible to declare global variables. In some cases global variables are needed and if not too many globals are used, the program will look like an electronic diagram. The events and how the data run through the program can easily be followed by look­ing at the block diagram. This programming technique is called flow programming.

In the end our program included more than 230 Sub- Vis which corresponds to more than 30 Mbytes of pro­gram code. The program code is devided into the follow­ing libraries:

• Controls library• Settings library• Globals library• Driver library• Execution library• Screen library• Log library• Network library• File operation library• Evaluation library• Task library

The Controls library is a type definition library which contains type definitions for all data clusters in the pro­gram structure. The two most important clusters are the Info cluster and the File Type cluster. The Info cluster contains information about general measurement parame­ters, stepper motor positions, execution parameters and error codes in case of fault. The File Type cluster is

a data cluster which contains all types of measurement data. These clusters run through almost every VI in the entire program

The Settings library contains default parameters for program execution and default file paths. The Globals library contains global variables and is used by different program libraries. The driver library contains instrument driver Sub Vis for the digitizer. The Execution library contains Vis controlling the execution. The most com­mon execution control VI in the program is the Cont EXEC ? Error VI; see for instance Fig. 6.2. If a switch is clicked on the task selection menu, or an error occurs, the global Change Activity is set to true. This indicates to the Cont EXEC ? Error VI that it is time to change task, by breaking up While Loops far down in the current SubVI. The sub program quits the current task and travels up to the highest level of the program, where a desired action is performed.

The Screen library contains Vis for displaying head­ers on the front panel and Vis to manipulate controls and indicators. Each task menu is made up by different front panels. Some front panels are specialised for a specific task, while others are used in many different menus. The Manual Control VI starts four different front panels; see Fig. 6.1. Together, they represents the Manual Control menu. The task selection menu belongs to the main pro­gram and it appears on every task Vis front panel. Nor­mally, the front panel frames are hidden.

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Fig. 6.1 Front panel of the Manual Control VI.

The Log library contains Vis for displaying and combin­ing data in the Log window. The Network library con­tains high level TCP/IP Vis for communication and data exchange between the computers in the system. The File operation library contains low and high level file opera­tions including dialogue windows. The file types used in

49

the system are the measurement specifications file, raw data and evaluated data. In all files there is an info file connected, with the function of a header. The Evaluation library contains Vis for DIAL evaluation and different methods of concentration and variance evaluation. The Task library contains Vis that perform the actual meas­urement tasks by using the other library functions. All the Task Vis are based on the state machine technique [19]. A state machine is made of two programs that run simul­taneously. One program takes care of all inputs from the keyboard and feeds the other program with data. The other program performs the actual tasks. In Lab VIEW this is solved by two While Loops; see Fig. 6.2. The up­per While Loop contains different tasks to be executed and the lower While Loop senses and controls the menu switches and the Case selection in the upper While Loop.

6.2 MainThe front panel of the main lidar program contains only the task selection menu, which represents different tasks that can be performed by the lidar system. Each task is represented by a VI, placed in the upper While Loop Case structure; see Fig. 6.2. This Case structure contains all task Vis. A task is executed by clicking the corre­sponding switch and the lower While Loop sets the Exe­cute Frame control to the proper Case. The main program opens the panel of the chosen SubVI and it runs as long as no other task has been selected or some error has oc­curred. In Fig. 6.2 the Manual Control switch has been clicked. When a new switch is clicked the program leaves the VI, closes its front panel and continues to the chosen Case. The Sequence structure to the left of the While Loop contains initialisation values.

50

6.3 Manual ControlWhen the lidar program is started or the manual control switch is clicked, the main program opens the front panel and starts the execution of the Manual Control VI.

In the Manual Control VI, the program starts by run­ning through the Cont EXEC Error VI, which makes an error check and a change activity check; see Fig. 6.3.If there is an error or if the change activity Boolean is true, the program runs through the false Case that con­tains a single wire and then returns to the main program. Otherwise the true Case is activated and the program opens the Dome Control VI, the Display Log VI, and the Display Text Manual Control VI. Further, it runs through the Setup VI, which sets up the counters for the stepper motors. Finally, the program enters the manual control While loop. The program remains in this While Loop as long as one has not clicked another switch in the task selection menu or some error has occurred.

In the While Loop the program continuously reads the controls and executes the SubVIs. The program controls the chopper, the dome cover, the heating fan, and the

PMT DC current measurement control by setting a digital line. All controls can be found in the front panel of the Manual Control VI; see Chapt. 4.

The Dome Control SubVI controls the stepper motors in the dome. The front panel of this VI is loaded and shown on the Manual Control panel; see Fig. 6.1. On the front panel there are two slides that control the frequency of the stepper motors. Negative values indicate decreas­ing angle of the dome. The dome position is displayed by two string indicators, Vertical Position and Horizontal Position, which are placed above the slides. Each indica­tor is graded in degrees, minutes, and hundreds. On the front panel there are also two switches: the Calibrate Dome and the Move Dome switch. If the Move! switch is clicked the dome moves to the position entered at the string controls on booth sides of the Move! switch. If the Calibrate! switch is clicked the dome moves to a vertical position of zero degrees and to a horizontal position of 180 degrees. Further, it calibrates the dome position against two sensors and resets the dome position in the info cluster.

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Fig. 6.3 Block diagram of the Manual Control VI.

51

Vertical Position Out 1

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Fig. 6.4 Block diagram of the Dome Control VI.

The While Loop in the Dome Control VI runs as long as the speed of the stepper motors is not equal to zero; see Fig. 6.4. Thus as long as the dome position is correct the execution just passes through the While Loop. If the ver­tical or the horizontal speed slide is drawn the While Loop will start looping. Since the slide controls are placed inside the While Loop, the speed input is updated each time the While Loop runs.

If the Move Dome switch or the Calibrate Dome switch is clicked the Contr Select VI sets a digital ring control in the Info cluster to tell the Motor Control VI that it should run continuously to a specific position.

In the move dome case, the new position is entered outside the While Loop by two string controls. In the calibrate dome case the dome is moved to the start posi­tion. With high accuracy the Fine Adjust VI adjusts the dome in the end of a move. Meanwhile, the actual posi­tion of the dome is presented by two string indicators which are placed inside the While Loop. They are up­dated each time the While Loop is looping.

Each time the dome has been moved the Log VI reg­isters its movement. If one of the local variables (the move dome, the calibrate dome switch) is set to true, the true Case in Fig. 6.4 is activated. The Log Pos VI creates log information and the Log Disp VI shows the informa­tion in the Log window on the screen.

6.4 Live CurveWhen the Live Curve switch is clicked, the main program activates the Live Curve VI which starts almost like the Manual Control VI; see Fig. 6.5. It runs through the Cont EXEC Error VI and opens up the Dome Control VI, the Display Log VI, and the Display Text Live Curve VI. Further, it runs through the Setup VI which sets up the counters for the stepper motors. Then it enters the While Loop which runs as long as no error or no Change Activ­ity has occurred.

On the left hand side of the While Loop the global digitizer setting variables are located. These settings give information to the system computer GPIB board about the digitizer GPIB address and slot number in the Camac Crate.

In the While Loop the Info cluster wire connects to the Sequence structure which contains the 8818 VI. This VI controls the digitizer, reads the data stored there which is then presented on a graph on the front panel. The digitizer VI has two further inputs: channels and offset. Data from these controls are memorised by two shift registers. As long as values do not differ from the previous values the Boolean input to the digitizer VI is false.

52

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Fig. 6.5 Block diagram of the Live Curve VI.

If some control changes the Boolean is set true and the digitizer reads the new settings and continues to execute. Further, if we follow the Info cluster line it runs through the Dome Control VI and Cont EXEC Error VI as it does in the Manual Control VI. The chopper is controlled by a digital output called Dig Line VI.

In the While Loop two DAC Vis control the overlap prism angle in the receiver unit by sending out analogue values. The analogue output can be set between -10V to 10 V.

Finally, when another task switch is clicked or some error has occurred the program leaves the While Loop and closes the panels and the counters that belong to this panel.

6.5 Define MeasurementThe Define Measurement VI is used for creating meas­urement specification files. The VI is built up by a state machine. The function of this state machine is similar to the Main VI. The lower While Loop handles the input actions from the user while the upper While Loop takes care of the actual task; see Fig. 6.6. The program uses a local variable (Execute Frame) to control which frame to run in the upper While Loop.

In the Sequence structure on the left hand side of the upper While Loop the Open File VI opens the Species Data file for reading of the proper resonance wavelength.

The Setup VI initiates the stepper motor counters. Below this Sequence structure there is another Sequence struc­ture which contains the initialisation of the front panel controls and screen handling Vis. The Define Measure­ment menu is built up in frame 1 by different SubVIs; see Fig. 6.6. They are the Text Define Measurement VI, the Eval Display VI, the Display Log VI, and the Dome Control VI. When all initialisation has been executed the program enters the two While Loops.

The upper While Loop contains six different Cases where Case 3 is not in use. As it can be seen in Fig. 6.6, there are two wires which are connected to shift registers. The wire called File Types is a large cluster designed to contain all information about a measurement. The cluster contains data with the following headings Species, Meas­urement Info, Measurement Specification, Measured Raw, and Evaluated.

The program starts with Case 0, where the program reads the Measurement Parameters and the Temp Digit­izer controls. Then, it reads species data from a file and stores it into the File Type cluster and writes the on wavelength in the Measurement Parameters group. The program initiates the digitizer with a VI called Dig Contr

Jnit. Finally, the small Sequence structure, to the right of the Dig Contr Init, sets the Execute Frame control to 1 which is the next Case to run if no error has occurred or no switch has been clicked.

53

Fig. 6.6 Block diagram of the Define Measurement VI.

When the program enters Case 1 the digitizer starts to measure one cycle. This is done by the Dig contr VI; see Fig. 6.7. All data cycles are stored in the File Type clus­ter for further analysis later on. If the measured data is out of range the Digi Failure VI indicates this on the screen, and the Execute Frame control is set to 1. This means that the same Case runs again until proper values have been measured. Otherwise the program continues to Case 2.

In Case 2 the program enters the Cycle Run Contr VI; see Fig. 6.8 and checks if the digitizer has run the number of cycles entered in the Temp Digitizer Settings group. If so, one Sequence of cycles has been completed and the wire below the VI symbol is set to true and the program returns to Case 0 and starts to measure a new sequence of cycles.

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Fig. 6.7 Case 1 of the Case structure in the Define Measurement VI diagram.

54

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Fig. 6.8 Case 2 of the Case structure in the Define Measurement VI diagram.

This is done in a Sequence structure to the right of the Dome Control VI. If a measurement sequence is not completed, the program continues to measure and accu­mulate cycles in the File Type cluster by returning to Case 1. After the Cycle Run Contr VI has been run, the Div Raw Data VI divides the measured data and the Disp Eval VI evaluates the data and presents the results on three graphs. Information about how many cycles which have been executed is wired from the Cycle Run Contr VI to the Div Raw data VI and the Disp Eval VI. The Signal Processing group and the Evaluation Options group feed the Disp Eval VI with evaluation parameters.

The program continues to the Dome Control VI which works in the same way as the Manual Control VI, and finally the program enters the Sequence structure where the Execute Frame control decides which frame to execute next (described above).

When the Select File switch is clicked the program enters Case 5; see Fig. 6.9. In this Case the Data Files Dialog VI opens a dialogue window and creates a new measurement file. Then it returns to Case 0 and the measurement process described above starts again.

After a measurement file is created the Store Direction switch and the End of Sweep switch are activated. If the Store Direction switch is clicked the program enters Case 4; see Fig. 6.10. The Mod M. SP Clus VI writes the cur­rent digitizer settings together with the End of Sweep control (if clicked) to the File Type cluster. Further, the program enters the Write File VI which writes the Meas­urement Parameters and the Digitizer Setting groups to the created Measurement Specification file. The two groups are located in the File Type cluster. Furthermore, the action is shown in the Log window by the Log Fi/St VI and finally, the program returns to Case 0.

Fig. 6.10 Case 4 of the Case structure in the Define Measure­ment VI diagram

After a number of measurement directions have been selected, the user ends the defining procedure by clicking the Abort Define Measurement switch. Then the program enters Case 6; see Fig. 6.11. In this Case the Close File VI closes the Measurement Specification file and the Info file. A dialogue window opens and asks if the measure­ment specifications file is to be saved or deleted. In Fig. 6.11 the delete Case is shown. Finally, the program con­tinues to the Sequence structure shown to the right in the Case and sets the Execute Frame control to 0 and the program returns to Case 0.

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Fig. 6.9 Case 5 of the Case structure in the Define Measurement Fig. 6.11 Case 6 of the Case structure in the Define Measure- VI diagram. ment VI diagram

55

As mentioned before the program enters the Eval Display VI in Case 2. This VI evaluates and presents the result of a measurement on three graphs as shown in Fig. 4.4. The Eval Display VI is used in the Define Measurement panel, the Run Measurement panel, and in the Evaluate Direction panel.

The outline of the Eval Display VI diagram is shown in Fig. 6.12. It is mainly built up by two Case structures. The large Case structure to the right of the diagram per­forms the task, while the smaller Case structure to the left of the diagram decides if the task should be performed or not.

Starting with the left Case structure, the Show Pres Settings switch decides whether or not the Case is true. It also decides if the Presentation Setting should be seen on the screen; see down to the left in Fig. 4.4. The reason with this option is that in the Define Measurement panel and the Run Measurement panel, there is the possibility to select how often the graphs should be updated. The graphs are updated each cycle or when the program has run the number of cycles according to the Show Pres Settings. If the left Case is true, as shown in Fig. 6.12, the Pres Settin VI reads the Presentation Settings input and counts how many cycles the program has run. When the sum is equal to the Digitizer Settings, the VI gives a true output which makes the right Case true and the graphs are updated.

If the Show Pres Settings switch is false the left Case makes the right Case true then the task will be performed

every time the Eval Display Vi is called. This option is used by the Evaluate Direction panel.

If the input to the right Case structure is false, the program just runs through the Case structure. If it is true, the program starts with entering the Cut Spike VI; see Fig. 6.12. This VI measures where the start spike is in the lidar return signals and deletes all data measured before the start spike. Thus in this way the system sets the zero range coordinate.

The program continues to the Eval Dir VI placed in the true Case to the right. If the Cone switch is clicked the Eval Dir VI evaluates raw data according to the Eval Settings control and the result is stored in the File Type cluster. The result is then shown on the Cone Curve graph. The Make c/v D VI is only used to create two Y- scales, one for the concentration and one for the standard deviation of the concentration.

The Case structure placed on top of the Eval Dir VI decides whether or not the raw data should be filtered before presentation on the On/OfftBack- and the DIAL graph. This is selected with the On/Off/Back Source switch. By clicking the DIAL and the On/Off switch the user decides if the DIAL curve and the On/Off/Back curve are displayed on the screen.

Finally, the unmentioned symbols in the right Case in Fig. 6.12 are used to autoscale the graphs and to make the resolution correct.

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Fig. 6.12 The Eval Display VI diagram.

56

6.6 Run MeasurementThe Run Measurement VI runs when the Run Measure­ment switch is clicked on the main panel. Its function is to execute a measurement sequence, which has been de­fined with the Define Measurement VI. A measurement sequence generates raw data, which are saved on a file in the evaluation computer.

The VI is built up by a state machine; see Fig 6.13, and has a similar construction to the Define Measurement VI. In Fig. 6.13 the upper While Loop contains seven Cases which correspond to the different tasks.

The Run measurement. VI Starts with the Sequence structure down to the left in the diagram. Here the pro­gram opens up the Vis used in this panel; the Eval Dis­play VI, the Display Log VI, and the Display Text Run Measurement VI.

The program continues to the upper Sequence structure on the left hand side of the diagram. In this Sequence structure the program reads the global file paths for spe­cies data, raw data, measurement specification, and temp data files. In the species data file the program reads wavelength and differential cross sections for the actual species. Then the program initiates the stepper motor counters with the Setup VI.

Later the program continues to the state machine; see Fig. 6.13. The program stops in Case 0 and waits for an occurrence signal created by the lower While Loop. When a switch is clicked an occurrence is generated and the Execute Frame control tells the upper While Loop which Case it should run. The state machine runs as long as a switch in the task selection menu is not clicked. If a switch is clicked the program leaves the While Loops and enters the Sequence structure down to the right of the diagram, where it closes used Vis.

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Fig. 6.13 Block diagram of the Run Measurement VI.

57

If the Select File switch is clicked the program enters Case 5; see Fig. 6.14. Immediately a dialogue window is opened twice by the Data Files Dialog VI. The first time for selecting a Measurement specification file to run and the second for creating a raw data file in which the meas­ured raw data will be saved. Then, the program adds the global variables Source Distance and Source Angle to the info file. These parameters are used to measure the wind direction of a plume from a smoke stack, see Chapt. 4.3.

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Fig. 6.14 Case 5 of the Case structure in the Run Measurement VI diagram.

The program continues to the Open File, the Read File, and the Close File VI. In these Vis the program opens the species file and reads the resonance wavelength and the differential cross section for the selected species. Then the Disp Runm VI updates the upper panel data and the program writes the number of sweep repetitions to be performed.

At the same time the program enters the Create Temp Eval VI which creates a temporary file where the real­time evaluated data are stored. Thus the evaluation com­puter is able to read the evaluated data at once and pres­ent the results by the Presentation program. Finally the program enters the Sequence structure and returns to Case 0.

After a measurement specification file is loaded, the measurement is started by clicking the Start Measurement switch, which causes the program to execute Case 1; see Fig. 6.15. In this Case the Read File VI reads the meas­urement specification file. If the Read File VI does not read an end of file mark the program continues to the false Case as shown in Fig. 6.15.

In the false Case the program reads the digitizer set­tings and the desired position from the File Type cluster. It updates the setting indicators on the screen. Then it enters the Contr Select VI which causes the Motor Con­trol VI to move the dome to a specific position. This VI creates pulses which control the stepper motors until they have reached the wanted position. The Fine Adjust VI

checks if the dome has reached the wanted position pre­cisely. If not, the VI adjusts the position a few steps.

After the dome has been moved the program enters the Dig Contr Init VI, which initiates the digitizer and prepares it for measurements. Then the program calls the Start Wind Meas VI, the Log Pos VI, and the Log Disp VI which updates the Log window. Finally, the program continues to Case 2.

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Fig. 6.15 False Case in Case 1 of the Case structure in the Run Measurement VI diagram.

When the program has completed a sweep the Read File VI detects an end of file mark in the measurement speci­fication file. This causes the program to execute the true Case; see Fig. 6.16. In the true Case the Rep left indicator is subtracted with one and then checked if the program has repetitions left to run. If the program has repetitions to run, it enters the inner false Case and the Move File Mark VI moves a file mark to the beginning of the meas­urement specification file. Finally the program continues to Case 1. This means that the next sweep will start from the beginning of the measurement specification file.

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Fig. 6.16 True Case in Frame 1 of the Case structure in the Run Measurement VI diagram.

58

If there are no repetitions left to run, the program enters the inner true Case and a dialogue window will appear, • letting the user know that the measurement is completed; see Fig. 6.17. Then it executes Case 6, saving the raw data file; see Fig. 6.21.

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Fig. 6.17 Case 1 of the Case structure in the Run Measurement VI diagram.

When the dome has been moved and the digitizer initi­ated in Case 1, the program continues to Case 2 for data sampling and to Case 3 for evaluation; see Fig. 6.18-6.19. In Case 2 the program enters the Dig contr sampl VI, which samples one cycle (8 on, 8 off, and 2 background measurements) of data according to the digitizer settings saved in the measurement specification file. If the meas­ured data are out of range, the Dig! Failure VI indicates this on the screen, and the program goes to Case 2 again for another try if no switch has been clicked. If a switch has been clicked, the Execute frame control will change value and the program will continue to the desired Case. However, if the measured data seem to be all right the program continues to Case 3.

Fig. 6.18 Case 2 of the Case structure in the Run Measurement VI diagram.

In Case 3 the Cycle Run contr VI checks if the program has run the number of cycles which is specified in the measurement specification file; see Fig. 6.19. If so the VI gives a measurement ready signal to the program that it has finished one measurement direction. When the pro­gram leaves the Cycle Run contr VI it enters the Div Raw data VI and the Disp Eval VI for evaluation and presen­tation on screen in real-time. This is done exactly as in the define measurement panel. Finally, the measurement ready signal makes the program continue to Case 4 after it has fulfilled its task in this Case; see Fig. 6.20. If not enough cycles has been accumulated the program returns to Case 2 for further data sampling or to another Case if a switch has been clicked.

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Fig. 6.19 Case 3 of the Case structure in the Run Measurement VI diagram.

In Case 4 the program reads the mean value of the wind speed and the wind direction with the Stop wind meas VI and the Read wind meas VI. The Div Raw data VI di­vides the accumulated raw data with the numbers of cy­cles performed in the specific measurement direction. The global variable Cycles Acc provides information about how many cycles that have actually been run. The Mod Raw clus VI writes the dome position into the File Types and the Write File VI writes the raw data to a file. Then the events are presented on screen by the Log Fi/St VI and the Log Dis VI which show and update the Log window.

The Write one dir data file VI evaluates the averaged raw data according to Eval Settings and stores it in a temporary file on the evaluation computer for presenta­tion in real-time. When the program leaves the VI it en­ters a small Case where the Set Me R VI alerts the evaluation computer that another evaluated direction has been saved on a temporary file. Finally, the program re­turns to Case 1 to read further measurement instructions from the measurement specification file.

59

Site

Fig. 6.20 Case 4 of the Case structure in the Run Measurement VI diagram.

After a measurement has been completed the program enters Case 6; see Fig. 6.21. In this Case the program starts with closing the temporal file, which contains evaluated data. Then it opens a dialogue window, which asks if the raw data file is to be saved or deleted. Finally, the program returns to Case 0 and waits for an occurrence from the lower While Loop.

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Fig. 6.21 Case 6 of the Case structure in the Run Measurement VI diagram.

6.7 EvaluationThe Evaluation VI evaluates raw data and saves the result in an evaluated measurement file. The result contains concentration curves and the variance of the concentra­tion for measured species. The VI is built up by a state machine and has a similar construction to the Define Measurement VI and the Run Measurement VI. The dia­gram is shown in Fig. 6.22.

The two Sequence structures to the left contain start­ing parameters, which must be set before the program enters the state machine. The upper Sequence structure contains only one frame in which the program gets in­formation about the default file paths for raw data files and evaluated data files. The lower Sequence structure contains two frames. Sequence 0 opens up the Vis which are used in the panel. They are the Display Log VI, the Eval Display VI, and the Display Text Evaluation VI. In sequence 1 the program initiates front panel controls. After the program has been initiated the program contin­ues to the two While Loops. The upper While Loop con­sists mainly of nine Cases which perform the tasks. In fig. 6.16 it can be seen that the upper While Loop starts at Case 0. The program enters Case 0 and waits for an oc­currence signal from the lower While Loop. It will be sent only if one of the switches down to the right on the front panel is clicked.

In the upper While Loop three shift registers are seen. The register on top contains the File Type cluster in which the program temporarily saves most of the data. In the middle shift register the program gets information about which Case it will use. In the lower register the program temporarily saves the two parameter setting groups. The user controls these settings with the pull­down menu placed on the front panel.

60

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TTfeTUd'O d'Q'"d~H"a d d o o o d otiooQ

Fig. 6.22 Block diagram of the Direction Evaluation VI.

If the Select Raw Data switch has been clicked, the Exe­cute frame control will be. set to 4 and the lower While Loop creates an occurrence signal. Thus the upper While Loop is activated and the program enters Case 4; see Fig. 6.23. In Case 4 the program enters the Data Files Dialog VI which opens up a dialogue window, asking the user to enter the name of the new raw data file. With the Read File VI the program continues to read data from the measurement info file. In the measurement info file the program receives data about the type of species, meas­urement, and how many repetitions the system has made for each direction.

The program then enters the Open File VI and the Read File VI and reads data from the Species Data file. From this file the program receives information about the resonance wavelength and differential cross section for the measured species. The Disp Dir Ev VI shows the measurement parameters on the top of the panel. Finally the Close File VI closes the species data file and the pro­gram continues to Case 1; see Fig. 6.24.

Fig. 6.23 Case 4 of the Case structure in the Evaluation VI dia­gram

61

In Case 1 the program enters the Read File VI which reads raw data for one direction. If the program reads an end of file mark this will be indicated on the screen and the program continues to Case 0. If no end of file mark is read the program continues to Case 3.

[Reads NedRaw Data Dusld

Fig. 6.24 Case 1 of the Case structure in the Evaluation VI dia­gram.

In Case 3 the Disp Eval VI evaluates raw data for one direction and displays it on three graphs; see Fig 6.25. This VI is also used in the Run Measurement VI and the Define measurement VI. At the same time the program reads the actual dome position from the File Type cluster and displays it in two position indicators. The two pa­rameter setting groups give information about how the data should be evaluated via the Trans Settin VI. The data from the two parameter setting groups are then wired to a shift register in the Case structure. Thus the program knows how to treat raw data in all Cases. Finally, the program returns to Case 0 and waits for a switch to be clicked.

Evd a dkecbon and displays U

Fig. 6.25 Case 3 of the Case structure in the Evaluation VI dia­gram.

The user can access all measured directions by clicking the Go Forward switch and the Go Backward switch. If the Go Forward switch is clicked the program enters Case 1; see Fig. 6.24. If the Go Backward switch is clicked the program enters Case 2; see Fig. 6.26. In this Case the Read File VI tries to read a previous cluster in the raw data file. If the Read File VI senses a beginning of file mark, the program enters the true Case and the Move File Mark VI puts the file mark to the beginning of the raw data file. Meanwhile the beginning of a file is indicated on the screen by the Beg of File indicator. Finally, the program returns to Case 0. If the Read File VI does not find a beginning of file mark, the program just runs through the false Case and continues to Case 3 for raw data evaluation.

i IGoesBockwa sand Reeds a Riw Data Ouster 1

1 E1 ^

!

1

KMeaKKtMMMMOKMMCMMm

1 ,---------------------------------------------------------1

Fig. 6.26 Case 2 of the Case structure in the Evaluation VI dia­gram.

If the Create Eval File switch has been clicked, the pro­gram enters Case 5; see Fig. 6.27. In this Case the Data File Dialog VI opens a dialogue window and asks the user to write the name of a new Eval Data file. The Move File Mark VI sets the raw data file mark to the beginning of the file. Finally, the program returns to Case 0 and waits for the next action.

Deetei Evaluated Data Ftet

Fig. 6.27 Case 5 of the Case structure in the Evaluation VI dia­gram.

62

When an evaluated data file exists, it is possible to save evaluated raw data in two different ways. The user can save each direction separately or all remaining directions at the same time. If the Store Direction switch is clicked the program enters Case 6; see Fig. 6.28. The Write One Dir Data File VI evaluates raw data from the File Type cluster according to the shifted parameter settings and writes it to the evaluated data file. Each direction is able to have its unique combination of evaluation parameters. Thus the Eval Data file contains evaluated data together with information about how the data was evaluated. Fur­ther, the Log Fi/St Eval VI makes a log string and passes it to the Log Disp VI. Thus each saving action is shown on the front panel Log window by the Log Disp VI. Fi­nally, the program returns to Case 0, awaiting the next action.

! Hwwgpwgwwwwawwwiwwwtwwa

Fig, 6.28 Case 6 of the Case structure in the Evaluation VI dia­gram,

If the Store All Directions switch has been clicked the program enters Case 7; see Fig. 6.29. In this Case the Write Eval Data File evaluates and saves all remaining directions according to the Signal Processing settings and the Evaluation Option settings. When all directions are evaluated and saved the VI gives an End of File message which is indicated on the screen. The program then enters the Sequence frame 0 in Case 7, where the program opens a dialogue window, which alerts the user that all data have been evaluated. Finally, the program continues to Case 8.

Evaluate! and tloret the iett of (Section* in the Bel

ASDirecbomhthe Raw data file are evaluated

Fig. 6.29 Case 7 of the Case structure in the Evaluation VI dia­gram.

Case 8 is reached if the Store All Directions switch or the Abort CreateEvalFile switch is clicked; see Fig. 6.30. In this frame the Close File VI closes all open files and a dialogue window appears which asks if the evaluated data file is to be saved or deleted. Finally, the program returns to Case 0, awaiting new tasks.

You have abated a cation of evaluated measurement Re I Select if you want to save or delete:

Evaluated Data Fie PathInfo FBc Path

Fig. 6.30 Case 8 of the Case structure in the Evaluation VI diagram.

63

6.8 PresentationThe Presentation VI reads evaluated data files and pres­ents it on the computer screen. It can be run from booth the system computer and the evaluation computer. This VI also works as a state machine; see Fig. 6.31.

When the Presentation VI is started the program en­ters Sequence structure to the left of the lower While Loop, where the program initiates panel controls and sets the colour of the graph, shown on the front panel. Before the program enters the state machine, it initiates eight matrixes in which all data for every show option are stored while this program runs. Each matrix is connected to a shift register. Thus the program remembers previous data and is able to, for instance, average evaluated data. Below that area the program receives the default file paths. This information is then stored in the File Type cluster for access by other Sub Vis. The Info cluster is shifted around and records if an error occurs.

The lower While Loop controls the Case selection in the upper While Loop, the scale of the graphs and reads all inputs from the keyboard. All control terminals are placed to the left in the lower While Loop. If one of these controls is clicked the Execute Frame control will be set to a corresponding Case number. The Show control cor­responds to a pull-down menu on the front panel where the user selects if single or average sweeps should be presented. The Options control corresponds to a pull­down menu on the front panel where it is possible to se­lect between the following presentation options:

• Raw Concentration• Smoothed Concentration• Raw Variance• Smoothed Variance

The pull-down menu values are connected to two shift registers which are updated during each cycle of the While Loop. If the user changes a pull-down menu the lower While Loop generates a corresponding Show Op­tion value and the Execute Frame control is set to 1. The Show Option value (0-7) is based on the Option value and the Show value

The upper While Loop contains twelve Case frames which read, calculate, and present the result on the com­puter screen. The upper While Loop starts with Case 0; see Fig. 6.31. Case 0 contains a small Sequence structure in which the Execute Frame control is read. If no control on the front panel is clicked, the upper While Loop halts in Sequence frame 1. If the user clicks a switch or changes the show options, the upper While Loop receive an occurrence signal from the lower While Loop and the program continues to Sequence frame 2. The program reads the Execute Frame value, transfers all shift register data and continues to a new Case according to the Exe­cute Frame value.

k/eitia Ocanencd

(Smoothed i(SmoothcdRetidudVa

BawAvergaeConcI (Smoothed Average Coocj

PawAvetaoeCond (Smoothed Average Comj

Paw Average Readuaivi |awAveta2eRetidudVarianM|(Smoothed Average Residual V; Smoothed Average Rendud Variance!

llnfoout 1

Info in *1*3"

RecdclAddtoAl

GoBacfcwdl dor. Had

■ ‘X RangeRecalc IAddtoAl

■Y RangeiMatraScel ‘Range HetY-acatel /er.HtS

♦Ranger^

Fig. 6.31 Block diagram of the Presentation VI.

64

When the Select New File switch is clicked, Case 7 is activated and the program opens the evaluated data file, reads and closes the measurement info file and the spe­cies file; see Fig. 6.32. The Read Sweep VI reads the evaluated data file and stores concentration and variance data in the upper four shift registers. The concentration data is saved in the Raw Cone and in the Smoothed shift registers. The variance data is stored in the Raw Residual Variance and in the Smoothed Residual Variance shift registers. The Read Sweep VI also reads measurement information and presents it on six indicators placed on the upper area of the front panel. Finally, the program Resets the Sweep Nr indicator to one and continues to Case 11.

EvakakdOatafiePtiftEvalialeri&ataEvaOifflrmia

Spaces Data WavriencihMeamemert WaTypeofMaas

Fig. 6.32 Case 7 of the case structure in the Presentation VI diagram.

In Case 11 the program updates the shift registers without any data changes and sets all calculation controls to false; see Fig. 6.33. These controls are used later in the pro­gram to decide how to treat the evaluated data. Then the program continues to Case 1.

Raid: *1 evakiMrn Bociwul

Fig. 6.33 Case 11 of the case structure in the Presentation VI diagram.

In Case 1 the program reads the Show Options and the corresponding calculation control value placed inside the small Case structure down to the right in Case 1. If the value is true the program continues to Case 3 for presen­tation otherwise the program first makes a recalculation in Case 2; see Fig 6.34.

(aSSzH l~i

Fig. 6.34 Case 1 of the case structure in the Presentation VI diagram.

In Case 2 the Biline Inter VI smoothes data and returns the result in the proper shift register; see Fig. 6.35. Simul­taneously the corresponding calculation control is set to high to indicate that smoothing has been done. Finally, the program continues to Case 3.

roar«n d Rsk-OrfJ

inn(wScl

4rHIShxcotcnl J

Fig. 6.35 Case 2 of the case structure in the Presentation VI diagram.

In Case 3 the program enters a small Case structure to the left; see Fig. 6.36. This Case structure is controlled by the Show Option control and it selects input data to the Conv map p-r VI. If the Show Options control corresponds to a variance option, the Var(c) Matrix VI converts residual variance data from the shift registers to concentration variance. In all other Cases the inputs are guided straight through the Case structure.

65

The Conv map p-r VI coverts data from polar coordinates to rectangular coordinates. The output matrix from the Conv map p-r VI is presented on the sweep graph shown on the front panel. The VI output also connects to the Make Histo VI which converts data to fit a histogram and presents the result on two histograms and two indicators on the front panel. The indicators present the centre of gravity of the histograms. Finally, the program continues to Case 4. In Case 4 the program calculates the mean wind speed, the total concentration (pg/m) for the sweep area, and the total flux. Case 4 is reached if the program has previously run Case 3 or if the Recalculate switch has been clicked. In Case 4 the program starts entering a Case which is controlled by the Calculate Variance switch; see Fig 6.37.

rm MmLMSJHe cwnt-q rf or avfj

■ lSSHm. Hat!

Fig. 6.36 Case 3 of the Case structure in the Presentation VI diagram.

If this switch is clicked the program calculates the vari­ance of the evaluated total concentration with the Data Redu VI, the Biline Inter VI, and Calc tot v VI. These Vis take variance data for all directions and distances and calculate the total standard deviation of the total concen­tration. Depending on the Show value, the program enters either the small Case 0 or 1. Case 0 is shown in Fig. 6.37. The only difference between these Cases is that if the Show value is 1 the program calculates the total variance of an average of sweeps, and if it is 0, the program calcu­lates the total variance of the current sweep. If the Calcu­late Variance switch has not been clicked, the program sets the standard deviation for both the average sweep and the single sweep to zero.

The program continues to the Calc Wind D&S VI which calculates the wind speed and the wind direction. Then the program enters the Calc Flux & std VI which calculates the total flux and its standard deviation. All results are shown on the front panel. Finally, the program returns to Case 0 awaiting new orders.

************CtWatgWnd Di&Swed & FW

• t-LL-jOtic WnPaamsU

Fig. 6.37 Case 4 of the case structure in the Presentation VI diagram.

An evaluated data file contains in many cases several sweeps. The user clicks the Go Forward or Go Backward switch to select a sweep in a file. If the Go Forward switch has been clicked the program enters Case 8, see Fig. 6.38. The Read Sweep VI reads a sweep and stores the data in two matrixes; one with evaluated raw data and one with evaluated residual variance. It also updates the Wind Parameters, the Range Res and the Sweep Nr indi­cator. The program then ends this Case and continues to Case 11. If the VI cannot find an additional sweep in the file, an End of File indicator is set to true. Then the pro­gram returns to Case 0.

........... ................................ .................................. ....8 kf——

ISwwoN h|*t>tS«wHil

-

Lz Mwrtye’weWfil

Fig. 6.38 Case 8 of the Case structure in the Presentation VI diagram.

If the Go Backward switch is clicked the Read Sweep VI tries to read a previous sweep in Case 9. The procedure is similar to the Go forward Case; see Fig. 6.39.

66

Fig. 6.39 Case 9 of the case structure in the Presentation VI diagram.

If the Add Sweep to Average switch is clicked the pro­gram executes Case 5; see Fig. 6.40. The Calc Aver Ma­trix VI takes evaluated raw data and variance from the shift registers and adds it to the average shift registers. The VI simultaneously reads the wind parameters and adds them to the Wind Speed&DirAv control. The Nr of Av control is the number of averages done by the VI. Finally, the program returns to Case frame 0.

•"HfH"""................ .......................

Ttv/rd SoeedlbtAvfLnii-p^Av

— IWrdSceedlDrM Iff31 —1 Wind SptedLOtAvl |...

HfrfAvUiwi-l | |

Ludj

trtertofVAl

0-

Fig. 6.40 Case 5 of the Case structure in the Presentation VI diagram.

If the Clear Average switch is clicked the program enters Case 6 and the program resets all average shift registers; see Fig. 6.41. Finally, the program continues to Case 3 for presentation.

Fig. 6.41 Case 6 of the Case structure in the Presentation VI diagram.

When the Auto Map Sweep switch is clicked (see Fig. 6.31) the little Case structure in the lower While Loop is set to true and the lower While Loop reads, not only the controls on the front panel, but also the communication interface with the system computer. The Read dir ready VI output is set to true when a new direction is stored on the temporary evaluated data file. This causes the pro­gram to execute Case 10; see Fig. 6.42. The Move File Mark VI puts a file mark at the right sweep position in the file. The Read Sweep VI reads data for one sweep and puts the evaluated concentration and variance in the upper four shift registers. The VI also reads all wind data and sets the wind parameters.

Fig. 6.42 Case 10 of the Case structure in the Presentation VI diagram.

67

The program checks if the Read Sweep VI has detected an end of sweep mark. In that case it sets the file mark to a position right after the sweep end mark, which means that the Read Sweep VI will start reading from this posi­tion the next time it is called. Further the program checks the size of the variance matrix from the Read Sweep VI. If the size is zero the system computer has finished the measurement and no more sweeps are advisable. The program returns to Case 0 without updating the graph. A dialogue window also tells the user that the measurement is completed. In all other cases the program goes to Case 11 for presentation and then back to Case 0 awaiting new instructions. The presentation program reads the tempo­rary evaluated data file every time the system computer sends a direction ready flag, as long as the Auto Sweep switch is clicked.

7. AcknowledgementsThis work was supported by the Swedish Space Board. We want to give thanks to National Instruments in Stock­holm (especially Sofia Goranssson) for technical support and good ideas, Bertil Hermansson and Ake Bergqvist at the Department of Physics, Lund, for computer support and electronic design. We are grateful to Andrea Nord and Susanne Madsen for help with language correction. Finally, we want to give thanks to our supervisor Prof. Sune Svanberg and to Dr. Hans Edner for supporting us in this work.

8. References1. R. M. Measures, Laser Remote Sensing (John Wiley &

Sons, Inc, New York 1984).2. M. W. Sigrist, Ed., Air monitoring by spectroscopic

techniques, chemical analysis volume 127 (John Wiley & Sons, Inc, New York 1994).

3. R. Jamal and L. Wenzel, The Applicability of the Visual Programming Langugage LabVIEW to Large Real-World Applications, 11th IEEE Symposium on Visual Languages, Darmstadt (1995).

4. H. Edner, K. Fredriksson, A. Sunesson, S. Svanberg, L. Uneus, and W. Wendt, Mobile remote sensing system for atmosheric monitoring, Appl. Opt. 26, 4330-4338 (1987).

5. Operation and Maintenance Manual YG 680, 681 & 682 YAG Laser, Continuum (1989).

6. D. H. Nguyen and P. Brechignac, Tunable alternate double-wavelength single grating dye laser for DIAL systems, Appl. Optics 27,1906-1908 (1988).

7. Operation and Maintenance Manual TDL60 Dye Laser, Continuum (1989).

8. P. Weibring, M. Andersson, H. Edner, and S. Svanberg, Measurements of Industrial Emissions using Lidar and Wind Videography, to appear.

9. F. Melleg&rd, Lund Reports on Atomic Physics, LRAP (Diploma thesis), to appear.

10. AT-MIO-16DL User Manual, National Instruments (1993).

11. PC-TIO-10 User Manual, National Instruments (1993).12. AT-GPIB User Manual, National Instruments (1993).13. EtherLink III Parallel Tasking PCI Bus Master Network

Adapters User Guide, 3Com Corporation, USA (1995).14. LeCroy 8103, TR8818, MM 8103A, and 8901 User

Manual, Lecroy Inc. (1984).15. Instructions model 05305 Wind Monitor-AQ, R.M.

YOUNG COMPANY, (1989).16. Instructions model 05603 Sensor Interface Circuit, R.M.

YOUNG COMPANY (1990).17. Operating and Service Manual HIGHPAC A2.5K-10HR

and A3.4K-40R, OLTRONIX ELECTRONICS.18. R. J. Allen and W. E. Evans, Laser radar (LIDAR)

for mapping aerosol structure, Rev. of Sci. Instr.43, 1422-1432 (1972).

19. G.W. Johnsson, Lab VIEW Graphical Programming, McGraw-Hill 1994.

68

9. Appendix

9.1 Data Analysis VI Librariesf

Measurement Filters Signal Processing Linear AlgebraAC Sc DC Estimator Bessel Filter Autocorrelation AxBAmp Sc Frcq Estimate Buttetworth Filter Complex FFT A x VectorAmplitude and Phase Spectrum Cascadc->Direct Coefficients Convolution DeterminantAuto Power Spectrum Chcbyshev Filter Cross Power Dot Product

Cross Power Spectrum Elliptic Filter CrossCorrelation inverse MatrixHarmonic Analyzer Equi-Ripple Filter Decimate Linear EquationsImpulse Response Function FIR Filter Deconvolution Normalize MatrixNetwork Functions (avg) FIR Narrowband Filter Derivative x(t) Normalize Vector

Power 8c Frequency Estimate FIR Windowed Filter Fast Hilbert Transform Outer ProductScaled Time Domain Window HR Cascade Filter Fast Hardey Transform TraceSpectrum Unit Conversion 11R Filter with I.C. Integral x(t) Unit VectorTransfer Function HR Filter Inverse Complex FFT LU Factorization

Signal GenerationInverse Chcbyshev Filter Inverse Fast Hilbert Transform Cholcsky FactorizationMedian Filter Inverse FHT QR Factorization

Arbitrary Wave Parks-McCIcllan Inverse Real FFT SVD factorization

Chirp PatternStatistics

fbaic Finding Solve Linear Equations (extra input,

Gaussian White Noise Power Spectrum called by Linear Equations)

Impulse Pattern 1D, 2D, and 3D ANOVA Pulse Parameters Eigenvectors and Values

Periodic Random Noise Chi Square Distribution Real FFT Matrix Condition Number

Pulse Partem Contingency Table Threshold Peak Detector Matrix Norm

Ramp Pattern crfto Unwrap Phase Matrix Rank

Sawtooth Wave ctfc(x) Y[i]=Clip(X[i]} Pseudoinverse Matrix

Sine Pattern F Distribution Y[i]=X[i-n] Complex LU Factorization

Sine Pattern General Histogram Zero Padder Complex Cholcsky Factorization

Sine Wave Histogram Complex QR Factorization

Square Wave Inv Chi Square Distribution Regression Complex SVD Factorization

Triangle Wive Inv F Distribution Exponential Hr Complex Inverse Matrix

Uniform White Noise Inv Normal Distribution General LS Linear Fit Solve Complex Linear Equations

InvT Distribution General Polynomial Fit Complex Eigenvectors and Values

Windows Mean Linear Ht Complex Determinant

Blackman Window Median Nonlinear Lev-Mar Fit Complex Matrix Condition Number

Blackman-Harris Window Mode

Array & NumericComplex Matrix Norm

Cosine Tapered Window Moment about Mean Complex Matrix Rank

Exact Blackman Window MSE 1D and 2D Linear Evaluation Complex Pseudoinverse Matrix

Exponential Window Normal Distribution ID Polar To Rectangular Complex AxB

Flat Top Window Polynomial Interpolation ID and 2D Polynomial Evaluation Complex A x Vector

Force Window Rational Interpolation 1D Rectangular To Polar Complex Dor Product

General Cosine Window RMS Numeric Integration Complex Outer Product

Hamming Window Spline Intcrpolant Polar To Rectangular Complex Vector Norm

Hanning Window Spline Interpolation Quick Scale ID and 2D Generate a Special Matrix

Kaiscr-Bessel Window Standard Deviation Rectangular To Polar Test Positive Definite Matrix

Triangle Window T DistributionVariance

Scale 1D and 2D find Polynomial Roots

69

9.2 Data Acquisition for Lab VIEW

,SA£

Features

md EI5

/iAInsi

/rumen

/itatlon

/-Class

?/

DAQI

V

•roduc

VIs

/ / /V

/

Bus type AT AT AT AT AT AT AT EISA AT AT AT AT5 Plug and Play* V V 4 A1 V - _ - - _ -

DMA 4 4 V A/ 4 V 4 4 4 4 4 V

nstr

umcn

totlo

n 1Fe

atur

es

Instrumentation class counter/timers*

4 V V 4 V 4 - ~ - - - -

Gain Independent high-speed settling*

aj 4 4 A1 4 A1 4 A1 4 - - •1

Multiboard/multifunctionsynchronization*

V V ay A/ V 4 4 4 4 4 4

Shielded, latching metal connector

4 V 4 aI 4 V 4 - ** - - -

Input channels* 16 SE8 Dt

16 SE8 D1

64 SE 32 01

16 SE 8DI

16 SE8 D1

16 SE 8DI

16 SE8 01

4SESS

4SESS

- - 2SESS

& Max sampling rate (S/s) 1.25 M 500 k 500k 100 k 100 k 20 k 100 k 1M 51.2 k - - 51.2 kI Resolution (bits) 12 12 12 12 12 16 16 12 16 - - 16Range (V) ±10, ±5

OtolO±10, ±5OtolO

±10, ±5OtolO

±10, ±5OtolO

±10, ±5OtolO

±10OtolO

±16OtolO

±5 ±2.828 ±2.828

Gains 15,5,102050,100

125,102050400

125,102050,100

1,2,5,1020,50,100

125,1020,50.100

12.10,100

125,102050,100

i i — 1

Output channels 2 2 2 2 2 2 2 - - 6 - 2Resolution (bits) 12 12 12 12 12 12 16 - - 12 - 16Digital I/O channels 8 8 8 32 8 8 8 - - 8 32 -Counter/timers 2,24-bit

20 MHz2,24-bit 20 MHz

2,24-bit 20 MHz

2,24-bit 20 MHz

2,24-bit 20 MHz

2,24-bit 20 MHz

3,166lt 7 MHz

-

s Analog trigger V V V - - - - 4 4 - - 4§ Digital trigger 4 V 4 V a/ V 4 4 4 - - V

LabVIEW for Windows 4 V V V A1 4 4 4 4 4 a/LabWlndows/CVl for Windows

V 4 A/ 4 A1 4 4 4 4 4 4 4

LabWindows for DOS - V V V 4 V AJ 4 4 V A/g VirtualBench A* V V 4 V a! 4 4 4 V - 4I Measure N a/ 4 V - N 4 - - - aI - -

ComponentWorks 4 V a/ 4 V V 4 V - V V -

DAOWare V Af */ V a/ aJ 4 - - _ - -

NI-DAQ for Windows V V V V V V 4 4 4 a/ 4 VNTDAQ for DOS, DOS/V 4 V V V 4 4 4 4 4 4 a/ VPage number 3-25 3-25 3-25 3-29 3-29 3-33 3-36 3-48 3-52 3-56 3-62 3-148

70

ISA and EISA Low-Cost DAQ Products

Features

// / / / /

'V

Computer bus XT XT XT XT XT XT XT XTm Plug and Play - - V - - V - -

Input channels* 8SE4DI 16 SE - - - - - -Max sampling rate (S/s) 83.3 k 50 k

Resolution (bits) 12 12 - - - - - -i

5

Range (V) ± 5,0 to 10 ± 5,0 to 10

±2.5,0 to 5

- “ - — —

Gains 1,2,5,10,

20,50,100

1 - — - — —

Ana

log

Out

put

Channels 2 - 2 - - - - -

Resolution (bits) 12 - 12 - - - - -§• Digital I/O channels 24 16* 16 96 24 16* 8/16* 16

1 Counter/timers 3,1Gbit,

8 MHz

2,1Gbit

8 MHz- - - - 10,16bit

7 MHz

Triffier Digital trigger V - - - - - -

LabVIEW for Windows V V V V V V V V

LabWindows/CVI for Windows

V V V V V V V V

LabWIndows for DOS V V - V V - V V8?

VirtualBench V V - - - - - -Measure V V V - - - - -

wComponentWorks V V V V V V V

DAQWare V V - - - - - -NI-DAQ for Windows V V V V V V V V

NI-DAQ for DOS, DOS/V V V V V V V V V

Page number 341 345 359 365 365 369 372 373

71

9.3 Lab VIEW Instrument Drivers

LabVIEW GPIB Instrument DriversInstrument Drivers - OscilloscopesModd Number Instrument TypeGould 270 Waveform ProcessorOption for Gould 407X/9X Waveform ProcessorGould 1602 Dishing OscilloscopeGould 1604 Digitizing OscilloscopeGould 475 Digitizing QsdBcscopeGould 4062 Emitting OscilloscopeGovld4064 Digitizing OscilloscopeGould 4066 Digitizing OscilloscopeGould 4063 Digitizing OscilloscopeGould 4072 Digitizing OscilloscopeGould 4074 Digitizing OscilloscopeGould 4090 Digitizing OsdBoscopcGould 4092 Digitizing OscilloscopeGould 4094 Digitizing OscilloscopeHameg205-X OscilloscopeHamtg408 OscilloscopeHcwktt-Ibckud 5I80A DigitizerHovien-Packard 54100A Digitizing OscilloscopeHcwkn-Packard 541J0D Digitizing OscilloscopeHcwkn-^doucd 54111D l GSa/i 2-Chan nd

Digitizing OscilloscopeHcwktvlbckard 54120A Digitizing Oscilloscope

MainframeHcwlttr-Packani 5420QA Digitizing OscilloscopeHewlett-Packard 54501A 10 MSa/s Digitizing OscilloscopeHcwictt-fodtard 54502A 400 MSa/s 2-Channd

Digitizing OscilloscopeHcwktt-Ibdcud 54503A 20 MSa/s Dig tizing OsdUoscopcHcwten-Padcud 54505B 300 MHz 2-Channd

Digitizing OaaUosCopeHewlett-Packard 54506B 300 MHs 4-CHannd

Digitizing OscilloscopeHewlett-Packard 54510A Digitizing OscilloscopeHcwfctt-Ibdcard 54510B 300 MHx 2-Channel

Digitizing OscilloscopeHewlett-Packard 54512B 300 MHz 4-Channel

Digitizing OscilloscopeHewlett-Packard 54520A Digitizing OscilloscopeHewlett-Padajd 54522A Digitizing OscilloscopeHcwfctt-ftdtird 54540A Digitizing OscilloscopeHewlett-Packard 54542A 2-GSa/s OscilloscopeHewlett-Packard 546COA Digitizing OscilloscopeHewlett-Packard 546Q1A Diptizing OscilloscopeHewlett-Packard 54602B EHgi thing OscilloscopeHewlett-Packard 54610B Digitizing OsdBoscopcHewlett-Packard 54657 MeasurtmcndScoragc

ModuleHcwktt-Ibdtard 5472QA Digitizing OscilloscopebwmiDS6l21 Digtiring OscilloscopeIwaou DS66I2 Digitizing OsdBoscopcLcCrcyLS-140 Digitizing OsdBoscopcLcCroy7200 Digitizing OsdBoscopcLcGoy93l0 Digitizing OscilloscopeLeGoy 9314 Digitizing OscilloscopeLcCroy9400 Digitizing OscilloscopeLeCroy9420 Digitizing OscilloscopeLcCroy9450 Digitizing OscilloscopeNicolcc320 Digitizing OscilloscopeNiedet 400 Scries OstilloscopeNk»lct4094A/B Digitizing OscilloscopePhilips PM335QA 100 MS/s Digitizing OstilloscopePhilips PM 3382 Digitizing OsdBoscopcPimps PM 3384 Digitizing OscilloscopePhilips PM 3392 Digitizing OstiHosopcPhilips PM 3394 Digitizing OscilloscopeTektronix DSA 600 Digitizing Analyzer

Tdaronix RXD 710 Wtvcfbrm DigitizerTektronix KTD 720 DigitizerTektronix SCD 1000 Dig'tbxrTektronix SCD 5000 DigitizerTclaromxTDS310 50 MHz Dip tizing OsdBoscopcTektronix TDS 320 100 MHz Dig? tizing OscilloscopeTdaronix TDS 350 200 MHz Digitizing OscilloscopeTektronix TDS 420 150 MHz Digitizing OscilloscopeTektronix TDS 460 350 MHz Dtgjthii^ OsdBoscopcTektronix TDS 520 500 M Hz Digtinrtg OsdBoscopcTdaronix TDS 540 500 MHz Digrtmr^ OsdBoscopcTektronix TDS 620 500 MHz D^tizing OstilloscopeTektronix TDS 640 500 MHz Digitizing OsdBoscopcTektronix TDS 644 500 MHz Dtgiduflg OsdBoscopcTektronix TDS 820 6 GHz Digitizing OstilloscopeTektronix 7D20 DigitizerTektronix 390AD DigitizerTektronix 2212 60 MHz Digital Storage

OscilloscopeTektronix 2216 60 MHx Four Channd

Digitizing OstilloscopeTektronix 2230 100 MHz Dual Time Base

Digitizing OscilloscopeTektronix 2252 100 MHz OscilloscopeTektronix 2430A 100 MS/s 150 MHz Digitizing

OscilloscopeTektronix 2432 Digitizing OscilloscopeTdaronix 2440 500 MSfs 300 MHz Digitizing

OsdBoscopcTektronix 2465A Analog OscilloscopeTektronix 7612D DigitizerTektronix 7854 700 MHxV&vcform Processing

OsdBoscopcTdaronix 7912AD/HB DigitizerTektronix 11400 Dig thing OstilloscopeTektronix U800 Digitizing Oscilloscope

Instrument Drivers -MetersB&K2977 Phase MeterFluke 45 Digital MultimeterFluke 8502A Digital MultimeterFluke S505A Digital MultimeterFluke 8506A Digital MultimeterFluke 8520A Digital MultimeterFluke 8840A Digital MultimeterFluke 8842A Digital MultimeterGiga-tronks 8541 Digital Power MeterGiga-tronicx 8542 Digital Rawer MeterHewlcn-fcckard 437B Power MeterHewlett-Packard 438A Dual Channel Power MeterHcwkn-Jbekaid3437A High-Speed DC VoltmeterHewlett-Packard3456A Digital MultimeterHewlett-Ibckard 3457A Digital MultimeterHewiett-Kickard 3458A Digital MultimeterHewlett-Packard 3478A Digital MultimeterHewlett-Ptdcard 4192 LCR MeterHewlett-Packard 4263A LCR MererHewlett-Packard 4275A LCR MeterHcwlett-Ihckard 4276A LCZ MeterHewien-Padcard 8452A SpectrophotometerHewlett-Packard 34401A Digital MultimeterIofbtck305 WattmeterKdthlcy 192 Digital MultimeterKtithlcy 195A Digital MultimeterKtithky 196 Digital MultimeterKeithley 197A Digital MultimeterKtithky 199 System Multimetcx/ScannerKtithlcy 485 Picmm meter

Ktithlcy 580 Micro OhmmctcrKdthlcy6l7 ElectrometerKathfcy2000 Digital MultimeterKtithley 2001 System Multimetcr/ScanncrKdthlcy2002 Digital MultimeterKrithfcy6517 High Rcslmncc

Meter/Electro meterMo$earonJD2000 Joulcmcicr/RatiomcicrMotcctron4001 Inser Energy MeterNewport Oorp. 835 Optical Ibwcr MeterPhBipj PM 2534 Syttem DMMThdips PM 6304 LCR MeterPrana 4000 Digital MultimeterPrema 5000 Distal MultimeterPrana 6000 Digital MultimeterPrenu 6031 Digital MultimeterRohde & Schwarz URE3 RMS/Ifcafc VohmcterSiemens B3220 Digital MultimeterSolanron7061 Digital MultimeterSolan ron 7081 Digital MultimeterSoIamon7l51 Digital MultimeterStanford Research 715 LCR MeterStanford Research 720 ICR MeterTektronix DM 5010 Digital MultimeterTdaronix DM 5110 Digital MultimeterWind cl C£ Cdtcmurm PJM-4SJitter MeterWmdd &T Goltcrmann SF60 Error and Jitter Meter

Instrument Drivers -- Power SuppliesCalifornia Instruments

L Series IV PTAC Rawer Source

Hamcg8l42 Programmable Power SupplyHewlett-Packard 6030A Single-Output System

Power SupplyHewlett-Packard 6031A Rawer SupplyHewlett-Packard 6032A Rawer SupplyHewlett-Packard 6033A Power SupplyHewlett-Packard 603BA Ibwcr SupplyHcvricn-lhtkard G050A System DC Electronic Load

Main/lameHewlett-Packard 6051A System DC Electronic Load

MainframeHewlett-Packard 6624A Quad-Output System DC

Ibwcr SupplyHewkn-Badard 6625A Precision Dual-Output DC

Power SupplyHewlett-Packard 6626A Precision Quad-Output DC

Ibwcr SupplyHcwlctr-Pidcaid 6628A Precision Dud-Output DC

Ibwcr SupplyHewlett-Packard 6629A Precision Quad-Output DC

Ibwcr SupplyHcwlen-lbdtard 6632A Singfe-Output DC Ibwcr SupplyHew/ctt-PjckanJ 6633A Single-Output DC JbwrrSvppJyHewlett-Packard 6634A Single-Output DC Power SupplyHewlett-Packard 59501B Ibwcr Supply ProgrammerKtithky 213 Voltage SourceKdthlcy 220 Current SourceKtithky 228 Yoltagc/Cuntnt SourceKtithky 230 Voltage SourceKepco BOP488 Power SupplyKepcoSN488 Tower Supply ProgrammerKcfxxr SNR488 Ibwcr Supply ProgrammerPhilips PM 2811 Single Output Power SupplyPhilips PM 2812 Dual Output Power SupplyPhilips PM 2813 Triple Output Power SupplyPhilips PM 2831 Programmable Ibwcr Supply

Philips PM 2832 Programmable Ibwcr SupplyTektronix PS 2510G Ibwcr SupplyTdaronix PS 251 !G Ibwcr SupplyTdaronix PS 2520G Ibwcr Supply

72

LabVIEW GPIB Instrument Drivers (continued)Tektronix PS 2521G Ttioronix PS 5004 Tektronix PS 5010 Xantrec XKWSeries

Power Supply Power Supply Power Supply Power Supply

Instrument Drivers—SourcesAnrimi-Wihroo (5700 Series Swept Frequency Synthesizer Anritsu-Wihron 68000B Series Synthesized Sweep Generator Anritsu-Wihron 68100B Series Synthesized Sweep Generator Anritsu-Wihron 68200B Series Synthemed Sweep Generator Anriou-W»Itron 68300B Series Synthesized Sweep GeneratorB 6CK1049 B&K1051 Fluke 6060GigHronics7200 Series Hameg8l30

Hewlcn-Ptckard 3314A Hewlett-Packard 3325A

Hewlett-Packard 4140B Hewlett-Packard 8116A Hewlett-Packard 8341 Hewlett-Packard 8643A Hcwlctt-I^ckard 8647A Hewlett-Packard 8656B Hewlett-Packard 8657A/B Hewlett-Packard 8663A Hewlett-Packard 8770 Hewlett-Packard 8904A Hewlett-Packard 33120A

IxGoySlOO Philips PM 5193 Rohde fie Schwarz SMX Stanford Research DG535PG

Stanford Research DS335

Stanford Research DS340

Stanford Research DS345

labor 8550 labor 8551ItktrontxAFG 5101/5501 lektionixFGSOlO (Huron ix HFS 9003 Wav-etch 23

Wavetck75M7avetek271

Vt'awdc 295 Wtvttek395

Sine Gcneraror/Notsc Generator Sine GeneratorSynthesized RF Signal Generator Synthesized Microwave Sweeper Programmable Function Generator Function Generator Synthesized Fuocrioo/Swcep Generator Voltage Source Pulsc/Function Generator Synthesized Sweeper Signal Generator Synthesized Signal Generator Economy RF Signal Generator Economy RF Signal Generator Frequency Synthesizer Arbitrary Waveform Synthesizer Function Synthcsaa/Gcocrator Function/Arbltraty V&veform GeneratorArbitrary Function Generator Function Generator Signal Generator Digital Pulse and Delay Generator3 MHz Synthesized Function Generator15 MHz Synthesized Function Generator30 MHz Synthesized FunctionGeneratorFunction GeneratorFunction GeneratorProg. Arix/Function GeneratorFunction GeneratorStimulus System12 MHz Synthesized FunctionGeneratorArbitrary Waveform Generator 12 MHz Pulse/Function GeneratorArbitrary Wtvcform Generator Arbitrary Waveform Generator

Instrument Drivers - AnalyzersAnriou-Wifcron 2602A RF Spectrum Analyzer Anriuu-Wiltron 37200A Series Vector Network AnalyzerAudio Precision SYS-22G Audio Precision SYS-222G Audio IYcdsion SYS-322G IX:UC 5208 I Icwktt-pKkard 3561A I (cwkn-Padard 3577B 1 lewlett-Packard 4145B

System One Audio Analyzer System One Audio Analyzer System One Audio Analyzer Lock-In Analyzer Dynamic Signal Analyzer Network Analyzer Semiconductor Parameter Analyzer

Hewlett-Packard 4155 A Semiconductor Rvaroctcr Analyzer

Hewlett-Packard 4I56A SenticonduemrArametc: AnalyzerHewlett-Packard 851 OB Network AnalyzerHewlett-Packard 8566B Spectrum AnalyzerHewlett-Packard 8591E Spectrum AnalyzerHevriett-Rickard 8720 Network AnalyzerHevdett-Packard 8753 Network AnalyzerHewlett-Packard 8901A Modulation AnalyzerHewlett-Packard 8903A Audio AnalyzerHewlett-Packard 8903B Audio AnalyzerNewport Corp. SupcrCavity Optical Spectrum AnalyzerNorma-Goerz D6100 Wide Band Rawer AnalyzerScMumbager 1253 Gain-Phase AnalyzerTektronix AA 5001 Distortion AnalyzerTektronix CSA 803 Communications Signal AnalyzerTektronix CTS7I0 SONET AnalyzeTektronix 2754P Network AnalyzerTektronix 2782 Spectrum AnalyzerTektronix 2784 Spectrum AnalyzerTektronix 2792 Spectrum AnalyzerTektronix 2794 SpccmvnAnaJyzerTektronix 2795 Spectrum AnalyzerTektronix 2797 Spectrum AnalyzerTektronix 3001 Logic AnalyzerTektronix 3002 Logic AnalyzerTTC Fircbcrd 6000 Communications AnalyzerVoiccch PM1200 fower AnalyzerVoltedt PM3000A Universal Power Analyzer

Instrument Drivers - Counter/TimersAdvantest R5373P Microwave Counter/TuncrHIP Microwave 575B CounterEIP Microwave 578B CounterHewlett-Packard 5316A Universal CounterHcwlcn-Pukard 5334A/B Universal CounterHewlett-Packard 5335A CounterHewlett-Packard 5342A Microwave CounterHewlett-Packard 5345AHewlett-Packard 5313IA 225 MHz Universal CounterHewlett-Packard 53132A 225 MHz Universal CounterHewlett-Packard 53181A RF Frequency CounterPhilips PM6666 frequency CounterPhilips PM 6680 Programmable Timer/Coun terRacak Dana 1992 CounterRacal-Dana 1994 Universal CounterStanford Research 400 Gated Photon CounterTektronix DC 5004 Counter/TimerTektronix DC 5009 Counter/TimerTektronix DC 5010 Countcr/Tlmer

Instrument Drivers ■- CalibratorsEDCS20A CalibratorFIulic5101B CalibratorHulz5440B CalibratorPrcdsion Hirers 6201C Calibration OscillatorTektronix CG 5001/551AP Calibration Generator

Instrument Drivers ■- MiscellaneousAerotcdi Unidex 11/12 Motion ControllerAcrotedi Unidex 100 Motion ControllerAcroccth Unidex 400 Motion ControllerAudio Predrion ATS-I Audio Test SystemEG&G52I0 Lock-In AmplifierFluke 2240C DataloggerFluke 2620A Data Acquisition UnitHBM DMC Digital Amplifier SystemHBMMGC Measuring Amplifier System

Hcwlcrt-Padord 342IAHewlett-Packard 3488AHewlett-Packard 3497AHewlett-Packard 3S52A-44701A-44702A-44705A-44706A-44709A•447I3A-44715A-44721A-44722A-44724A-44726A-447Z7A-44728A-44730A-44732A

-44733A

Hcwlett-Ihckard 7470A Hewlett-Packard 7475A Hewlnt-Ibckaid 7550A Hewlett-Packard 8902A Hewlett-Packard 8920 Hewlett-Packard 8958A Hewlett-Packard 11713A KHchtcy 236 Kadiley237

Ktithlcy238

KeidilcyTOS Ka'thky 707 Kctthley7001 Keithlcy7002 Lakcsborc330

Leybold Infioon PG3 Measurements Group 2000 Neff System 470 Newport Corp. PMC20O-P Newport Corp. PM 500 Newport Corp. 855C Prechion Filters6201 RacakDanz 1250 Rod-LM30 Rod-LMlOODC Rod-LMI50AC Rod-L M300RT Rod-LM1088 Stanford Research 245 Stanford Research 250 Sanford Rescardi 510 Stanford Research 530 Stanford Research 630 Stanford Research SR810 Stanford Rescardi SRB30 Stanford Research 850 Tcac RD-200T Tektronix SG 5010 Tektronix SI 5010 Tektronix370A Tektronix 371A ValnlaQLlSO Tektronix THS 710 Tektronix THS 720

Data Acquisition/Control Urut Switch/Control Unit Data Acquisition Unit Data Acquisition System 5-1/2 Digit \Mtmetei High-Speed Voltmeter 20-Ch Relay Mux 60-Ch Single-Ended Relay Mux 20-Ch FET Mux 24-Ch FETMux 5-Ch Coumer/Totalher 16-Ch Digital Input 8-Ch AC Digital Input 16-Ch Distal Output 2-Ov Arbitrary Waveform DAC 4-Ch Voltage DAC 8-Ch Relay Actuator 4-Ch Track-Hold Mux 4-Ch 120 Ohm Strain Gage Mux4-Ch 350 Ohm Strain Gage Mux Digital Plotter Digital Plotter Digital Plotter Measuring Receiver RF Communications Test Set Cellular Radio Interface Aneouatot/Switch Driver Source Measure Unit High Voltage Source Measure UnitHigh Current Source MeasureUnitScannerSwitching Matrix MainframeSwitch SystemSwitch SystemAuto* tuning TemperatureControllerVacuum Gauge Controller A/D converter Data Acquisition System Motion System Motion System Programmable Controller FilterSwitch System Amp Ground Tester Hifct Tester HiRx Tester Resistance Tester GPIB InterfaceComputer Interfacc/NIM Crate Gated Intcg. fic Boxcar Averager Lock-In Amplifier Lock-In Amplifier Thermocouple Monitor Lock-In Amplifier Lock-In Amplifier DSP Lock-In Amplifier PCM Dau Recorder Low Distortion Oscillator Scanner Curve Tracer Curve Tracer Sensor Collector Hand-held Scopc/OMM Hand-held Scopc/OMM

73

LabVIEW VXI Instrument Drivers Tektronix VX4355 Tektronix VX4356

Model Number AD Data Systems 230122 OMv9IOO CytccCY/CX CytrcCY/8X8 CyrecCY/48X48 Cytec CY/32KC CytccCY/64K CytccCY/m Datron Wivctdc 1362 Datron Wavack I362S E1P Microwave 1140A EIP Microwave 114IA ElP Microwave 1142A FJPMioowavc 1230A EIP Microwave 1231A Gga-tronics 58542 Hewlett-Packard E1326A Hewlett-Rickard E1328A Hewlett-Packard E1330A/B Hewlett-Packard EI333A

Hewlett-Packard E1340A Hewlett-Packard EI345A Hewkn-Ibckard EI346A

Inrtrumcne Type 96-Ounnd Switch Trigger Delay Coaxial Matrix Switch Matrix Switch Matrix Switch Module Switch Module Multiplexer6.5- EKgit Multimeter6.5- Digit Multimeter Pulsed Microwave Synthesizers Pulsed Microwave Synthesizers Pulsed Microwave Synthesizers Microwave Counters Microwave CountersPeak and CW Rawer Meter5.5- Digit Multimeter 4-Channd D/A Converter Quad 8-bit Dipul VO 3-Gunnel Universal Counter TimerArbitrary Function Generator 16-Chan nd Rday Multiplexer 48-Gunnd Single Ended Rday Matrix

Hewlett-Packard E1466A Hewlett-Packard E1467A HewJecr-Pzekard E146SA Hewlett-Packard E1469A Hewlett-Packard E1472A Hewlett-Packard E1473A

Hewlett-Packard E1474A Hewlett-Packard E1475A

Hewlett-Packard EI476A

Hewlett-Packard El 740A

Interface Technology DG600 InterfaceTechnology IO100 Kinetic Systems V215

North Adamic 5388 Racal-Dana 1260-12 Racal-Dana 1260-13

Racal-Dana 1260-20 Racal-Dana 1260*30 Racal-Dana 1260-35

4 by64 Rday Matrix 8 by 32 Rday Matrix5 by 8 Matrix Switch 4 by 16 Matrix Switch 50 Ohm RF Multiplexer 50 Ohm RF Multiplexer Expander75 Ohm RF Multiplexer 75 Ohm RF Multiplexer Expander64 Channel Thermocouple Relay Multiplexer (50 MHz Time Interval Analyzer Card Digital Word Generator Digital I/O Module 32-Channd, 16-bit A/D ConverterSynchro/Resolver Processor Rday ActuatorSignal Switching/Rday Actuator ModuleRwer Switching Module Multiplexer High-Density Signal Scanncf/Muluplcxcr

Tektronix VX4357 Tektronix VX4363 Tektronix VX4365

Tektronix VX4366

Tektronix VX4367 Tektronix VX4372

Tektronix VX4374

Tektronix VX4385 Tektronix VX4730

Tektronix VX4750 Tektronix VX4790 Tektronix VX4801 Tektronix VX48D2 Tektronix/CDS 73A-256

Tektronix/CDS 73A-270

Tektronix/CDS 73A-308

Tektronix/CDS 73A-332

Hewlett-Packard E1347A

Hewlett-Packard E1352A

Hewlett-Packard E1355A

Hewlett-Packard E1356A

Hewlett-Packard E1410A Hewkir-lbckard El 411A Hcwlctt-Padard E1416A Hewlett-Packard E1420A/B Hewlett-Packard E1426A

Hewlett-Packard E1428A Hewlett-Packard E1429A/B

16-Channd Thermocouple Rday Multiplexer 32-Channd Single Ended VET Multiplexer8-Qunnd 120 Ohm Strain Gauge Rday Multiplexer 8-Channel 350 Ohm Strain Gauge Relay Multiplacer 6.5-Digii Multimeter 5-5-Digit Multimeter Ibwcr Meter Universal Counter 500 MHz Digitizing Oscilloscopel GSa/s Digitizing Oscilloscope 20 MSa/s 2-Ch Digitizer

Racal-Dana 1260-40 Racal-Dana 126045 Racal-Dana 1260-54

Racal-Dana 1260-64 Racal-Dana 1277 Series Racal-Dana 2251 Racal-Dana 2351 SehlumbcrgerSI 1270 Talon BE-64 Tektronix VX4223

Tektronix VX4234 Tektronix VX4236 Tektronix VX4240 Tektronix VX4250

MatrixHigh-Denrity Switch Matrix 1 GHz Terminated RF Multiplexer18 GHz Mkrowzve Switch Switching Modules Universal Counter/Iimer Time Interval Analyzer Frequency Response Analyzer Bus Emulator/Word Generator 160 MHz Universal Counter/Tuner Diptal Multimeter 6.5-Digit Multimeter Waveform Digitizcr/AnaJyzcr Waveform Tester

Tektronix/CDS 73A-334

Tektronix/CDS 73A-342 Tektronix/CDS 73A-353 Tektronix/CDS 73A-355 Tekrronix/CDS 73A-356

Tektronix/CDS 73A357 Tektronix/CDS 73A-372

Tektronix/CDS 73A-374

Tektronix/CDS 73A411 Tektronix/CDS 73A412 Tektronix/CDS 73A453

Hewlett-Packard E144QA

Hewlett-Packard E1445A Hewlett-Packard E1446A Hewlett-Packard E1460A Hewiett-ftekard EI463A Hewlett-Packard E1465A

21 MHz Synthesized Funcoon/Swecp Generator Arbitrary Function Generator Summing Amplifier/DAC 64-Chan nd Relay Multiplexer 32-Gunod 5-Amp Switch l6by 16 Rday Matrix

Tektronix VX4286

Tektronix VX4332

Tektronix VX4334

Tektronix VX4353

32-Channd Analog/Digital Input Module 40-Chan nd 2-Witc Relay Scanner Master 24-Channd 4-Wire RdayScmwct Muter32-Channd SPST Rday Switch

Tektronix/CDS 73A455

Wrvrtek 1375

Waverck 1395

LabVIEW Serial and CAMAC Instrument DriversSend Instrument DriversModd Number Aerotcch Unidex 100 Analog Devices 6B Series Analog Device jiMac6000 Emvtham 808/847 Fluke PM99 Fluke 97 Fluke 2625A HBMDMC HBM MGC Mctzler PM4£0O OhausGTScries SpccCDZA Tektronix 222

Instrument TypeMotion ControllerSignal Conditioning I/O ModulesModular I/O ProcessorDigital ControllerScope/MeterScope/MeterHydra Data Acquisition Unit Digital Amplifier System Measuring Amplifier System Balance BalanceSpectrometer Drive System Digitizing Oscilloscope

CAMAC Instrument DriversBiRa530I ADCDSPTcchnology 2010/2012 DigitizerJoctgerSlZ JoergerTR Series JorwaytiOA KincticSystems 3074 KincticSystems 3075 KmcticSyaems3112 KincticSystems 3361 KincticSystems 3514 KureticS/strans 3516 KincticSystems 3525 KincticSystems 3988 KincticSystems 4010

Sealer Digitizer Input Register Output Register Output Register DACStepper Motor ControllerADCADCTemperature Monitor GPIB Crate Controller Transient Recorder

KincticSystems 4020 LeCroy 2228 A LeCroy 2249SG LeCfoy 2256AS LeCroy 4434 LeCroy 6810 LeCroy 8210 LeCroy 8232 LeCroy 8901/8901A LeCroy TR88I8 LeCroy TR8837F LRS2550B

24-Channd DPST Rday Switch 20-Channd DPDT Rday Switch32-Channel SPOT Relay Switch 32-Channd SPST Relay Switch 24-Channd DPST/SPDT Rday Switch20-Channd DPDT Rday Switch32-Channd SPOT Rday Switch 48-Gunnd 2-Wire Reed Relay Scanner Slave24-Channd 4-Wire Reed Rday Scanner Slave Matrix Switch 12Gunnd, 16-Bft D/A Converter Function Generator Arbitrary Waveform Generator 40-Lrne Isolated Digital I/O 80-Une Digital I/O 12-Channd 16-Bit D/A ConverterArbitrary Pulse Pattern GeneratorRelay and High Voltage Lope Driver40-Channd 2-Wire Reed Rday Scanner Master24-Channd 4-Wire Reed Rday Scanner Master Dual Programmable Resistance 32-Channd SPST Rday Switch 24-Channd DPST Rday Switch 20-Channd DPDT Rday Switch32-Channel SPOT Rday Switch 4S-Channd 2-Wire Reed Relay ScannerSlave24-Channd 4-Wire Reed Rday ScannerSlave40-Line Isolated Digital I/O 80-Une Digital I/O1- Channel Mll^STD-1553A/B Bur Simulator2- Chaimd MIL-STD-I553A/B Bus Simulator20 MHz Arbitrary Function Generator50 MHz Arbitrary Function Generator

Transient DigitizerTDCADCDigitizerSealerDigitizerDigitizerADCGPIB Crate Controller Transient Recorder Transient Recorder Sealer

74