photovolt model 577pc reflectometer user’s manual

PHOTOVOLT

Model 577PC

Reflectometer

Users Manual

Photovolt Instruments Inc. Revision A

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WARNING This manual contains information and warnings, which must be followed to ensure proper and safe operation of your Model 577PC Reflectometer. For accurate results and safe use of the Model 577PC Reflectometer, correct operation and maintenance including periodic inspection are required. You should read the instruction manual paying attention to all warnings and notes prior to practical use and maintenance of your instrument. Cautions regarding operation of the Model 577PC Reflectometer are indicated by the following format throughout the instruction manual. Be sure to read and understand all of these cautions.

WARNING Indicates actions or conditions that pose (a) hazard(s) to the user.

NOTE Indicates actions or conditions that may damage your Model 577PC Reflectometer or result in inaccurate test results.

POINT Indicates information important for the accurate use of the Model 577PC Reflectometer system.

This document contains information for use by owners and operators of the Photovolt Instruments Model 577PC Reflectometer. Information in this document is subject to change without notice. This document is considered proprietary and no part may be reproduced or transmitted in any form or by any means, electronic or mechanical, for any purpose, without the express prior written consent of Photovolt Instruments. If copies are then permitted, they must contain this proprietary notice. 2012 Photovolt Instruments. All rights reserved.

Model 577PC Reflectometer

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Users Manual

(Revision A)

Photovolt Instruments, Inc.

6323 Cambridge St. Minneapolis, MN 55416 USA Telephone: 1-800-222-5711 Fax: 952-926-5498 Internet: http://www.photovolt.com E-mail: [email protected]


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1. Table of Contents 1. Introduction to the Model 577PC Reflectometer System 4 2. Unpacking the Instrument 5 3. Instrument Set-up 6 3.1. Power Adapter Module 6 3.2. Sensor (search unit) connection 6 3.3. Power on 6

4. Model 577A Front Panel Organization 7 4.1. Function Buttons 7 4.2. Shifted Functions 7 4.2.1. Difference Mode 8 4.2.2. Transfer Saved Readings 8 4.3. Reflectance Display 8 4.4. Color Select Buttons 8 4.5. Calibration Controls 9

5. Model 577PC Back Panel 10 5.1. Basic Connections 10 5.2. Earth Ground Connection 10 5.3. Digital Input/Output Connections 10

6. How the Model 577PC Measures Reflectance 11 7. Calibration Instructions 12 7.1. Filter Selection/Reflectance Display 12 7.2. Instrument Calibration 13 7.2.1. Calibration Memory Access (CALIBRATE) 13 7.2.2. Black Cavity/Zero Offset Calibration (ZERO) 13 7.2.3. Standard Plaque Value Entry (STD) 14

8. Saving and Transferring Reflectance Readings 15 8.1. Storing Readings 15 8.2. Transferring Stored Readings 15 8.3. Format of Stored Readings 15

9. Digital Inputs and Outputs 17 10. Computer Settings 17 10.1. Setting Time and Date 17 10.2. Updating the 577PC Software 17

11. Users Guide to Search Units 18 11.1. Types of Search Units 18 11.2. Type Y search unit 18 11.3. Type X Search Units 19 11.4. Type T Search Units 19 11.5. Type W Search Units 19 11.6. Type D Search Units 19 11.7. Color Filters 20 11.8. Specific Applications by Search Unit and Filter 21


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12. Simple Maintenance Procedures 22 12.1. Care and Maintenance of Calibration Standards 22 12.1.1. Environment: 22 12.1.2. Handling: 22 12.1.3. Operating Conditions: 22 12.1.4. Minor Cleaning (removal of dust): 22 12.1.5. Minor Cleaning (removal of surface contamination): 22 12.1.6. Severe Cleaning: 23 12.1.7. Recalibration Period: 23 12.1.8. Black cavity Standard: 23 12.2. Changing the Light Source Lamp 24

LIST OF FIGURES Figure 1. Model 577PC Reflectometer system with YA Search Unit ........................................4 Figure 2. 577PC console shipping carton contents......................................................................5 Figure 3. Search units and related items .....................................................................................5 Figure 4. Power Adapter ..............................................................................................................6 Figure 5. Model 577PC Front Panel.............................................................................................7 Figure 6. Model 577PC Back Panel ...........................................................................................10 Figure 7. Example of a Two-Point Calibration............................................................................12 Figure 8. ZERO Calibration........................................................................................................13 Figure 9. Plaque.........................................................................................................................14 Figure 10. Format in Excel for Saved Data ................................................................................15 Figure 11. Types of Search Units...............................................................................................18 Figure 12. Search Unit Apertures...............................................................................................18 Figure 13. Tristimulus Filter Characteristics...............................................................................20 Figure 14. Applications by Search Unit and Color .....................................................................21 Figure 15. Lamp Assembly .........................................................................................................24 Figure 16. Lamp Installation........................................................................................................24 Figure 17. 577PC-S Stainless Steel Model................................................................................. D

APPENDICES Appendix A - TROUBLESHOOTING GUIDE............................................................................................... A Appendix B - GLOSSARY OF TERMS........................................................................................................... B Appendix C - CONVERSION TO OTHER COLOR SPACES....................................................................... C Appendix D - 577PC-S ....................................................................................................................................D


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1. Introduction to the Model 577PC Reflectometer System

The new Photovolt 577PC reflectometer is similar to older models but, contains state-of-the-art electronics and has many new features including an embedded PC computer, Ports for a keyboard, a mouse, two USB devices, Ethernet, RS232 serial port, and a color display. Figure 1 shows a typical 577PC Reflectometer system with all its components. The type YA sensor head (search unit) shown is the most common type. Other search unit types may be supplied with black cavity standards and calibration plaques that differ in appearance from the ones shown. Please refer to section 13 of this manual for more information on the different search unit types available.

Figure 1. Model 577PC Reflectometer system with YA Search Unit


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2. Unpacking the Instrument The 577PC Reflectometer system is shipped on two cartons. The larger contains the

577PC console, the power adapter, power cord, operators manual, and warranty card. Identify all parts and part numbers against the list shown below. Only one power cord is supplied as required from the list. Other types may be available, please contact Photovolt Instruments for more information.

Operators Manual Rev. A 9957711P Model 577A Reflectometer console 0257720 Universal Power Adapter 4457004 Power cord (USA, Canada, Mexico type) - (England) - (Europe Germany) - Warranty Card 0130168

Figure 2. 577PC console shipping carton contents

The search unit, calibration plaque, black cavity, spare lamp, calibration certificate, and color filter(s) are shipped in the smaller carton. There are a lot of possible options so check the contents against the list of possibilities shown below.

Type YA search unit 0457711 Type WA search unit 0457720 Type TA search unit (with filters) 0457731 Type DA search unit 0457704 Type XA search unit

2457002 2457003

Color filters (for X,Y and D only) AMBER BLUE GREEN 2547001 Black cavity standard (not for D) 2657012 Black calibration plaque (for D only) - Brightness calibration Plaque (for W only) 2657030-2657049 Reflectance calibration plaque (X,Y,T) 2657050-2657069 Calibration plaque (for type D only) - Spare lamp for types YA, WA, TA, XA 1157707 Spare lamp for type DA only -

Figure 3. Search units and related items Report any missing, damaged, or incorrect parts to Photovolt Technical Service at

800-222-5711. If the shipment was complete and satisfactory, fill out the warranty card and mail to Photovolt.


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3. Instrument Set-up

3.1. Power Adapter Module The Model 577PC is supplied with a universal power adapter that steps any common power line voltage down to a safe 9 VDC. The power adapter is Energy Star rated, UL and CSA listed, and CE marked.

Connect the adapter output connector to the Power socket on the backside of the reflectometer. Connect the power cord to the adapter and plug into your power outlet. There is a small green indicator light on the top of the adapter that is illuminated whenever it is connected to a functioning power outlet.

NOTE

Do not attempt to power the 577PC from any source of power other than the Photovolt provided module. Doing so will void the warranty and may damage the instrument.

3.2. Sensor (search unit) connection Connect the coiled cord of the search unit to the SENSOR connector. The

search unit is connected to the Model 577PC via the 10-pin receptacle at the rear of the instrument. To attach the search unit, connect the 10-pin plug, on the end of the search unit cable, to the receptacle on the Model 577PC by lining up the notches on the connectors and turning the locking ring clockwise. To disconnect the search unit, turn the locking ring on the cable plug counter clockwise and carefully pull it away from the Model 577PC back panel. The cable connectors are polarized to prevent incorrect mating of the connector halves. Power should be turned off when attaching or disconnecting the search unit.

3.3. Power on Turn on the master power rocker switch. When it is on it lights up in a green color. This is a master power switch like those on the power supply on the back of your PC. It should be left on all the time. The red power button on the front of the 577PC is used to control operation of the instrument. When the red POWER button is pushed a red light will be lit on the front panel. If an operating 577PC is turned off with the master rocker switch it might cause a corruption of the internal solid-state storage and a loss of saved readings and calibration settings.

Figure 4. Power Adapter


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4. Model 577A Front Panel Organization

4.1. Function Buttons

The function buttons control basic reflectometer operation. The red POWER button turns the 577PC off and on. When the red POWER button is pushed a blue light just above the red POWER button and a red light near the number display will be lit up. The blue light indicates that power is on and the red light indicates that the computer is booting up. When the boot up is complete, the red light will turn off and the number display will light. When power is on the blue light above the power button is illuminated. Since the embedded PC controls all functions As long as the blue power light is lit the internal computer is running.

The HOLD button freezes the reflectance display reading at its current value. The display remains frozen and the red light just above the hold button stays on until the hold button is pushed a second time.

4.2. Shifted Functions The HOLD button also functions as a SHIFT key to change the function of the

CALIBRATE and STD buttons. Press and hold down the HOLD button and then press CALIBRATE or STD buttons to start the functions described below.

Figure 5. Model 577PC Front Panel


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4.2.1. Difference Mode While pressing the HOLD button pushing the CALIBRATE button puts the 577PC in the

difference mode. When the difference mode is active all three color select lights are on. The reflectance

display shows the difference in percent between the current reading and the reading at the time this mode was started.

The difference mode can be used to directly display variations across a large sample as

the search unit is moved about. It can also be used to show variations across a group of samples or differences from a master sample. It can also directly display the darkening of filter paper in the ASTM fuel stability test.

To exit the difference mode just repeat the HOLD plus CALIBRATE button procedure.

Unlike other modes the 577PC does not stay in the difference mode when power is turned off and back on again.

Turn on the master power rocker switch. When it is on it lights up in a green color. This is a

master power switch like those on the power supply on the back of your PC. It should be left on all the time. The red power button on the front of the 577PC is used to control operation of the instrument.

4.2.2. Transfer Saved Readings

While pressing the HOLD button pushing the ZERO button tells the 577PC to

transfer the internally stored reflectance readings to a USB flash memory stick. See section 8 of this manual for a complete description of saving and transferring reflectance readings.

4.3. Reflectance Display The digital display shows the sample reflectance in percent from 0.00 to 99.9%. This display is continuously updated unless the hold button is used. When the reading is less than 10% the hundredths digit is shown. During abnormal conditions error messages may be shown such as: Lo Hi or Err. The display is also used during instrument calibration.

4.4. Color Select Buttons The color select buttons select the reflectometer operation for each color: AMBER, BLUE , or GREEN. Each color is calibrated individually and those settings are selected with these buttons. This allows quick readings of a sample in each color especially when using the type T search unit that has a color filter selection wheel. The appropriate color must be used to match the color of light emitted by the search unit.


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For the type W search unit the blue color is always selected. The 577PC retains its color mode setting when powered down.

4.5. Calibration Controls The calibration controls are used to set the black ZERO and standard plaque STD calibration for each of the three colors. The calibration procedure is described in section 6 of this manual. When used together with the HOLD button the calibration controls have a second function as described above in section 4.2.


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5. Model 577PC Back Panel

Figure 6. Model 577PC Back Panel

5.1. Basic Connections Only the power input and the search unit sensor need be connected for basic

operation. The master power switch should be left on in most situations. Use the red power button on the front panel to switch the 577PC on and off.

5.2. Earth Ground Connection If needed the 577PC reflectometer chassis can be connected to an earth ground using the connector shown in figure 6. This is a standard banana plug socket. Photovolt can provide the mating plug and cable upon request.

5.3. Digital Input/Output Connections The use of the computer input/output connections is described later in this manual. By far the most common usage will be to plug a USB flash memory stick into either USB connector. Saved reflectance readings are normally stored internally and from time to time they are all written to the USB memory stick file in Microsoft Excel spreadsheet data format. Also, when needed the 577PCs program can be updated from a file on a USB memory stick. The keyboard and display connections are needed only for special operations such as setting time and date.


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6. How the Model 577PC Measures Reflectance In order to measure reflectance ratiometrically, a two-point calibration is required.

This is done on the Model 577PC via a black cavity standard and a standard plaque. The black cavity standard is designed to have nearly zero reflectance, which provides the first of the required two calibration points. Standard plaques are specially calibrated enamel plaques with a known reflectance, and provide the second point of the two-point calibration.

The photosensor array in the search unit produces a voltage that is proportional

to the amount of light that shines on its surface. However, the photosensor does not produce zero voltage in the absence of light. This no light voltage must be nulled out or zeroed to produce the first calibration point. This first calibration point is then referred to as the dark or zero offset.

When a plaque of known diffuse reflectance is placed on the search unit, it

produces a voltage in the photosensor array proportional to the light reflected from the plaque. This provides the second or reference point of the calibration. Figure 5 shows graphically how the Model 577PC is calibrated.

When a sample is placed on the search unit, the photocell produces a voltage

that is usually between the two calibration points. Since the photosensor output is linear, the sample voltage is directly proportional to its reflectance.

Note: For best accuracy we recommend choosing a reference plaque such that the

plaques reflectance values are near or higher than the expected brightest sample. For best accuracy when a large range of sample reflectance values is expected, we recommend that two different standard plaques be used, one for the brighter and one for the darker samples. This is especially desirable when working with low reflectance samples (less than 20%) such as roast coffee.


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Figure 7. Example of a Two-Point Calibration

7. Calibration Instructions The Model 577PC uses internal flash memory to store the current mode and the

calibration values for each of the tristimulus filters. The values for one calibration plaque are retained when the instrument is powered down. Thus it is not necessary to reenter the plaque calibration values before each recalibration if you use the same calibration plaque. The 577PC should be allowed to warm up for at least 30 minutes before calibration or use. To avoid the warm up period you may leave the instrument on continuously. If left on continuously the 577 draws less than 25 watts of power and lamp life will exceed 1.5 years. A detailed overview of the Model 577PCs calibration procedure follows:

7.1. Filter Selection/Reflectance Display When measuring samples the Amber, Blue, and Green buttons are used to

select appropriate calibration curve for the specific tristimulus filter in the search unit. When one of these three buttons is depressed, the corresponding LED above it will illuminate and indicate which filter calibration curve is being used.


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POINT The calibration curve of the 577PC will be different for each of the three filter channels. Be sure to select the correct filter channel for the filter in the search unit. Incorrect filter channel settings will result in erroneous reflectance measurements.

When filters are changed in the search unit, the corresponding channel should be

selected via the Amber, Blue, or Green buttons. Filters and their corresponding memory settings can be changed at will, once the Model 577PC has been calibrated. Only those filter channels that are being used for samples need to be calibrated.

The normal display mode displays percent reflectance of the sample.. This is the

default display mode and is active when NOT in calibration mode (whenever the CALIBRATE, or STD lights are extinguished).

A samples reflectance value is calculated based on the calibration curve saved in

memory for the currently selected filter channel (Amber, Blue, or Green). If the calculation results in a reflectance value well beyond 100% the display will indicate an overrange condition by displaying (Hi. ). (Reference Section 6.6)

7.2. Instrument Calibration As stated earlier, a filter channel (Amber, Blue, or Green) should not be used for

reflectance measurements until it has been calibrated at least once. Calibration requires setting both the zero offset (ZERO) and a standard plaque value (STD). These values are set by using the CHANGE button as described in the following sections.

7.2.1. Calibration Memory Access (CALIBRATE)

To calibrate the Model 577PC, the desired filter channel must be selected via the Amber, Blue, or Green buttons. Next, the CHANGE button is depressed causing the CHANGE LED to illuminate. The instrument is now ready for a two-point calibration, starting with the zero offset setting and followed by the standard plaque value setting.

7.2.2. Black Cavity/Zero Offset Calibration (ZERO) The first step of calibration is to set the BLACK CAVITY zero offset (dark current correction). The black cavity standard should be placed on the search unit before this measurement is taken. Once the black cavity is in place and the CALIBRATE mode has been entered, as described above, the ZERO button should be depressed. This will cause the CHANGE light to go out and normal reflectance display to resume. While the black cavity standard is on the search unit, the Model 577A should display between 0.10 and -0.10. If it does not produce this value the calibration should be repeated. Figure 8. ZERO Calibration


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7.2.3. Standard Plaque Value Entry (STD) After the zero offset has been set, the second CALIBRATION PLAQUE calibration point can be determined by using a Photovolt standard plaque. To set the standard plaque value, follow the procedure below: Place the standard plaque with the recessed glazed surface toward the search unit. Press the CALIBRATE button. The CALIBRATE light will Illuminate, then press the STD button. The STD light will illuminate as will all three filter color lights (Amber, Blue, and Green). The display will show the assigned reflectance value for the previously entered standard plaque. Read the assigned plaque reflectance value for the selected color from the label on the back of the plaque. Enter the standard plaque value from the plaque label into the Model 577PC by using the Amber, Blue and Green buttons to increment the tens, units, and tenths digits respectively. The digits will individually increment between 0 and 9 when the buttons are depressed. Standard plaque values of between 00.0 and 99.9 may be entered. Once the display reads the correct standard plaque value, depress the STD button a second time. The STD LED will extinguish, as will the CALIBRATE LED. Normal reflectance display will resume and the display should be identical as the standard plaque value ( 0.2%) after the standard plaque value is entered.

The reflectometer is now ready for sample measurements on the newly calibrated

color channel. For best results let the instrument warm up for at least 30 minutes before calibration. During use calibration should be rechecked periodically by replacing the standard plaque on the search unit. If the plaque value ( 0.5%) is displayed when the standard plaque is replaced on the search unit, then the instrument is still in calibration. Otherwise, calibration should be repeated.

POINT

Two-point calibration (zero offset and standard plaque entry) must be done at least once for each filter and filter channel combination to be used. If the search unit to be used does not require multiple filters, calibration need be done only on the filter channel required for use with the selected search unit. The 577PC remembers the calibration information but it is still good practice to check it fairly often.

Figure 9. Plaque


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8. Saving and Transferring Reflectance Readings

8.1. Storing Readings

The Model 577PC stores the current reflection reading whenever the button on the side of the search unit is pressed. The HOLD light flashes for a second to indicate the data have been saved. The most recent 100 readings are stored in internal flash memory. Once 100 readings have been saved subsequent readings will be saved and the oldest readings will be deleted.

8.2. Transferring Stored Readings

To retrieve the stored readings plug a USB memory stick into either USB connector. Wait a minute or two for the memory stick to be recognized. Then press the HOLD button and keep it down while pressing the ZERO button. All of the saved readings in internal memory will be transferred to the USB memory stick in comma delimitated format suitable for import into Microsoft Excel or other spread sheet programs. This file is quite small so it takes only a fraction of a second to transfer.

Transferring the data does not erase it from the 577PC. New readings are just

added until there are 100 at which point adding a new reading erases the oldest one. If the memory stick is full, unformatted, or write protected the data will not be

transferred. You can test the memory stick for compatibility with the 577PC by copying some sample data to it from a PC. If it passes this test it should also work with the 577PC.

8.3. Format of Stored Readings

Figure 10. Format in Excel for Saved Data


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The readings are in comma delimited format used with a spreadsheet program. Each reading is one line. The image below is what Excel shows for six readings. Types are REF for reflectance and DIF for difference. Colors are A for amber, B for blue, and G for green.


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9. Digital Inputs and Outputs The 577PC with its embedded PC was designed for normal use without the need of separate computer peripherals such as keyboard, display and mouse. However, the 577PC can be used with such computer peripherals to change settings in the 577PC. The USB, keyboard, mouse, color display, and network ports on the 577PC are all PC standard ports. If a peripherals work on your PC they will also work with the 577PC. USB keyboards and mice can also be used.

10. Computer Settings The two situations where the connection of a display and keyboard are needed

are in setting the internal clock time and date and updating the 577PC software.

10.1. Setting Time and Date

When shipped from Photovolt the 577PC internal clock is set to universal (GMT) time and date. To change this you will need to connect a keyboard (or USB keyboard) and a display to the 577PC. You must start this procedure with the 577PC power turned off. Push the red power button to turn on the 577 and immediately start repeatedly pushing the DELete key on the keyboard. This will cause the BIOS setup page to appear on the display. Use the arrow keys and PAGE UP and PAGE DOWN keys to set the desired time and date and then save and exit by pushing the F10 key.

Once the BIOS setup is completed the computer will restart the reflectance

program. Unless you are sure you know what you are changing do not modify the other BIOS settings as they may keep the reflectance program from operating properly.

10.2. Updating the 577PC Software

The 577PC software can be easily updated by the user. Normally the updated program is supplied on a USB memory stick or sent by email.

When the update is sent by email you will receive a file with the name:

577_580_update.tar.gz. Copy this file to the root directory of a USB memory stick. The file is about 125Kb. The USB stick that is used does not have to be empty and may contains other files on them.

Connect a PC or USB keyboard, and the memory stick to the 577PC. Connecting

a monitor to the DISPLAY connector is desirable but not necessary. Wait a couple of minutes for the new items to be recognized by the 577PC. Then push only the U key on the keyboard, just the U key, nothing else. The reflectance display will go blank and the new software will be installed. This only takes a few seconds. Wait a minute for it to


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complete and then type: RESTART followed by [ENTER]. The new software will start and you can disconnect the memory stick and keyboard. Or you can push the red power button to turn off the 577PC. It will be running the new software when turned back on.

11. Users Guide to Search Units

Figure 11. Types of Search Units

11.1. Types of Search Units Currently there are five different types of search units available for the 577A reflectometer. The search units are interchangeable and some users have more than one type allowing use with different samples. They differ in their use of color filters and the aperture or area of sample measured.

Figure 12. Search Unit Apertures

11.2. Type Y search unit The type Y is by far the most commonly used search unit. It uses a removable tristimulus color filter to filter the light shining on the sample. Per CIE standards amber,


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blue, and green tristimulus filters can be inserted one at a time in the side of the search unit. For full color measurements the reflectance at all three colors must be measured. More commonly the sample only needs measurement with one color. The type Y must be used with a filter installed. The type Y along with the W, X, and T are designed with the geometry of the light source and the photodetector arranged to minimize or eliminate any effect on the measurement due to the samples glossy or shiny surface. Usually the type Y is used with a green filter. This gives a generic reflectance reading since green is near the center of the eyes response band and near its most sensitive color frequency. When in doubt use green. A blue filter is used with near white samples such as paper, talc, pigments and other powders. Amber is used for coffee beans and ground coffee. Infrared and ultraviolet parts of the lamp spectrum are filtered out before reaching the sample so optical brighteners do not affect the readings. The type Y measures reflectance of the sample in a circular area 0.8 inches (20mm) in diameter. For a smaller measurement area see type X.

11.3. Type X Search Units The type X search unit is the same as the Y except that the sample area that is measured is much smaller. The measured area is a circle only a 0.375 inch (9.4mm) in diameter. This allows accurate measurement of especially small or varied samples or those with somewhat curved surfaces. Unless the smaller sample area is specifically needed the type Y is preferred.

11.4. Type T Search Units Type T search units have the same specifications and work the same as the type Y except they are supplied with all three color filters mounted in a rotating Turret. This makes it easier when measuring each sample with all three colors.

11.5. Type W Search Units The type W search unit was designed specifically to measure the brightness of paper samples to a old TAPPI standard. It is sometimes also used with near white powders. The W uses a built in blue filter for the light source. The blue filter can not be changed or removed. Like the types Y and T search units the type W measures a 0.8 inch (20mm) diameter circular area on the sample.

11.6. Type D Search Units Like the Y and T the type D search unit uses an amber, blue, or green tristimulus filter to filter the light striking the sample. Unlike the others the type D measures the average reflectance over a large 2.8 inch (72mm) diameter area. The


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common uses are changes in cloth reflectance due to soiling or cleaning and coffee beans or ground coffee. Because of the large area of measurement the type D can not be used with samples that have a glossy or shiny surface.

11.7. Color Filters

All the search units use some type of color filter. The types D,X,Y, and T search units utilize amber, blue, or green tristimulus color filters. Tristimulus filters have a wide bandpass and meet original CIE specifications allowing calculation of values in other color coordinate systems such as Lab or WYZ. These filters also prevent the passage of infrared and ultraviolet light to the sample. The following table outlines the bandpass of these tristimulus filters:

Filter CIE

Transmittance Range

Transmittance Peak (nm)

Amber 540 660 nm 590 Green 450 620 nm 550 Blue 410 490 nm 440

Figure 13. Tristimulus Filter Characteristics


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11.8. Specific Applications by Search Unit and Filter

Industry Application

Type Search

Unit Filter Test Method or

Standard Biomedical Erythema, skin color, frog skin, etc. Y/T

Green-Tristimulus and others

Numerous by users

Burlap Grading Y/T Green-Tristimulus By user

Ceramics (Tile & Porcelain)

Color classification. Opacity, or contrast ratio

Y/T

Varies Varies

ASTM E97 ASTM C347 ASTM C346 ASTM C584

Chemical Dry powders, plastics Y/T Varies By user

Cosmetics Sun tan lotion by skin color, lipstick, face powders, etc.

Y/T Tristimulus By user

Detergents Reflectance before and after cleaning, both cloth and hard materials

Y/D Green-Tristimulus By user

Distillate Fuels High temperature fuel stability test Y/T Green- Tristimulus ASTM 6468

Food & Agricultural

Color comparison of food products such as coffee, potato chips, peanut butter, cocoa, catsup, tuna, sugar, browning of baked goods or potatoes

Y/T/D Tristimulus

Coffee Brewing Institute, SCAA, etc. By user

Industrial Products

Color of finished products. Waxes, powders, flat solids, tiles

Y/T

Y/T Tristimulus

By user ASTM E97 ASTM D1455 ASTM D3052

Metal Finishing Color Y/T Tristimulus By user Packaging Color comparison Y/T Tristimulus By user

Paint & Varnish Color Hiding power and contrast ratio

Y/T Y/T

Tristimulus Green Tristimulus

Federal Test Method No. 141; ASTM D523

Pharmaceutical Powder brightness, product color, packaging All types Varies

Plastics Color Y/T Varies By user ASTM D2457

Pulp & Paper Brightness Opacity Color

W Y/T Y/T

Built-in Green-Tristimulus Tristimulus

TAPPI Methods ASTM

Textile Rapid and convenient color matching of textiles Y/T/D Tristimulus By user

Figure 14. Applications by Search Unit and Color


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12. Simple Maintenance Procedures The Photovolt model 577PC reflectometer system does not require any regular

preventative maintenance. Normally all that is needed is to keep the instrument relatively clean and free of dust. In especially dusty environments it will probably be necessary to use low pressure air to blow out dust that collects down inside the search unit aperture and on the filters.

12.1. Care and Maintenance of Calibration Standards The model 577PC reflectance measurements can only be as accurate as the

calibration standard plaque used for calibration. Normally the human eye can detect only about a 5% change in reflectance and it is easily fooled by changes in color tint. The 577PC reflectance resolution is 0.1%. Thats fifty times more sensitive than the eye. Obviously any dirt or contamination you can see on the calibration plaque is going to have a big detrimental affect on the accuracy of the readings.

12.1.1. Environment:

Avoid exposing the calibration plaque to sources of heat, chemicals, dust, or oil. Contamination of the surface of the plaque will result in decreased accuracy. Avoid damaging the surface of the plaque. Scratches, chipping of the surface, or dulling of the surface will result in incorrect readings and make cleaning difficult.

12.1.2. Handling:

Avoid touching the reading surface of the calibration plaque. Fingerprints, dirt, oils, or any other surface contamination will result in incorrect readings. Handle the plaque only by the anodized plaque holder. When placing the plaque on a table or other flat surface, keep the reading side facing up, or place it face down on a clean, soft, dirt-free surface such as a lint-free cloth.

12.1.3. Operating Conditions:

It is suggested that the 577PC, search unit and calibration plaque be allowed to equilibrate to room temperature with the power turned on for a period of one hour before conducting critical calibrations.

12.1.4. Minor Cleaning (removal of dust):

Remove dust by gently brushing the surface of the plaque with a soft camel-hair brush or blow dust off of the surface with clean, dry, oil free, filtered compressed air. A pressurized canister of air for cleaning photographic lenses is suggested for this purpose.

12.1.5. Minor Cleaning (removal of surface contamination):

Remove fingerprints, smudges, and other slight surface contamination by moistening the surface of the plaque with a thin film of pure water or methanol. Use a clean, soft, lint-free, non-abrasive cloth to gently wipe the surface of the plaque. Use a second dry cloth to remove all traces of moisture from the plaque. Visually inspect the


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surface for cleanliness. Never use common household or kitchen counter cleaners as they often contain fluorescent brighteners that are supposed to make things look brighter or bluer in color. Methanol removes these brighteners.

12.1.6. Severe Cleaning:

Remove severe contamination from the surface of the plaque as quickly as possible. Extended exposure to foreign material may permanently stain or alter the reflectance of the plaque. Use a clean, soft, lint-free, non-abrasive cloth moistened slightly with a non-fluorescing laboratory detergent (such as Sparkleen) to gently wipe the surface of the plaque. Use a second dry cloth to remove all traces of moisture from the plaque. Visually inspect the surface for cleanliness. If successive cleanings do not remove the contamination from the surface of the plaque, either replace the plaque or return it to Photovolt for recalibration. A calibration plaque that shows extensive physical wear or scratches on its surface should be replaced.

12.1.7. Recalibration Period:

Photovolt recommends that the calibration plaque be returned for recalibration once per year. More frequent calibration may be required due to improper handling or storage. Plaques that are heavily used should be inspected frequently for scratches and/or other physical damage. Damaged plaques must be recalibrated or replaced depending upon the extent of the damage.

12.1.8. Black cavity Standard:

Only the inside surface of the black cavity is used so as long as it is clean and undamaged it should work properly. The black cavity does not need to be calibrated.


24

12.2. Changing the Light Source Lamp P/N 0857708

LAMP

BRACKET LOCKWASHER NUT

Figure 15. Lamp Assembly INSTALL LAMP INTO BRACKET AS SHOWN. TIGHTEN NUT FINGERTIGHT ONLY. LAMP WITH BRACKET. MOUNT AS LOW AS POSSIBLE, LEAVE SCREWS LOOSE. MOUNTING SCREWS 4 PLACES WIRE CONTACT Mount lamp with bracket as shown BLOCK leaving the 4 screws slightly loose. Locate the lamp assembly as far downward as possible. Connect lamp wires to contact block. Connect the search unit to the reflectometer console and turn on the power.

Figure 16. Lamp Installation Move the lamp bracket up/down or tilt side to side until the sample aperture on the end of the search unit is evenly illuminated. The easiest way to check the illumination is to hold a piece of paper against the aperture and check for a evenly lit circle.


25 26

Operators Manual Warranty

Photovolt Instruments provides this manual as is without warranty of any kind either expressed or implied including but not limited to the implied warranties, merchantability, or fitness for a particular purpose.

Some states do not allow disclaimer of express or implied warranties in certain transactions; therefore, this statement may not apply to you. This manual could include technical inaccuracies or typographical errors. Changes may be periodically made to the information herein; these changes will be incorporated into new editions of the manual. Photovolt Instruments may make modifications and/or improvements to the products described in this manual at any time. It is possible that this manual contains information about or makes reference to products or services that are not released in your country. Such information or references must not be construed to mean that Photovolt Instruments intends to announce such products or services in your country. Contact your local Photovolt Instruments representative for further information. The foregoing warranties are in lieu of all other warranties, expressed or implied, including but not limited to, the implied warranties of merchantability and fitness for a particular purpose. Issued: Feb 2012 P/N 9957710P Revision A


A

Appendix A - TROUBLESHOOTING GUIDE 1. Problem: After STD calibration the reading goes back to 0.00

a. Search unit not connected. b. Lamp is burned out

2. Problem: Hi is always displayed

a. Wrong filter channel is selected for the filter or search unit in use b. Selected filter channel needs recalibration. c. No filter installed.

3. Problem: Reflectance values greater than 100.0 are displayed

a. 577PC was improperly calibrated. b. Wrong filter channel is selected. c. No filter is installed. d. Search unit is pointed at a light source

4. Problem: 577PC display wont change

a. 577PC was left in HOLD mode (reference Section Error! Reference source not found.).

5. Problem: 577PC always displays 0.0

a. Search unit is not connected. b. Lamp is burned out

6. Problem: 577PC is ON but search unit lamp is OFF

a. Search unit not connected b. Lamp is burned out.

7. Problem: Power light is on but the display is blank and LED lights are OFF

a. Internal computer is still booting up. Wait for 30 seconds. If additional assistance is required call Photovolt Technical Service at 1-800-222-5711.


B

Appendix B - GLOSSARY OF TERMS The following is a glossary of terms used throughout this manual. 1. Search Unit: An optical sensor designed for a specific reflectance measurement such as

brightness or diffuse reflectance. Search units are lettered according to their function, i.e., Y, W, T, etc.

2. Filter: A piece or sandwich of colored glass that can be installed in some search units to

give it a particular optical response. The most commonly used filters are the Amber, Blue, and Green tristimulus filters used in color matching work.

3. Standard Plaque: A small calibration plate with a surface of known reflectance. 4. Photodetector: A device that produces an electrical current proportional to the light that

shines on its surface. 5. Reflectance Photocell: The Photodetector that measures the light reflected from the sample

surface. 6. Gain: The amount of amplification applied to the photosensor output signal before it is

converted to digital information for the computer. 7. Filter Channel: One of the three electronic channels (Amber, Blue, Green) of the Model

577PC. Each channel has its own linearity settings and memory locations, which allow it to function independently of the other two.

8. Calibration Memory: Each filter channel has three independent memory locations associated

with it. These locations are:

Zero Offset Memory: The memory locations that store the current produced by the Model

577PC when a Black cavity standard is placed on the attached search unit.

Calibration Reflectance Memory: The memory locations that store the current produced by the Model 577PC when a standard plaque is placed on the attached search unit.

Standard Plaque Value Memory: The memory locations that store the standard plaque

reflectance values entered during calibration. 9. 4-digit LED Display: The group of four display digits that display the percent reflectance. 10. LED: Light Emitting Diode - The small, red, rectangular indicators above the HOLD, Amber,

Blue, Green, STD, and CALIBRATE buttons on the front panel.


C

Appendix C - CONVERSION TO OTHER COLOR SPACES

A spreadsheet template for Microsoft Excel is available from Photovolt to convert the

amber, blue, and green reflectance measurements from the PHOTOVOLT MODELS 575, 670, 577, and 577PC Reflectance Meters to tristimulus color coordinate values. Values for yellowness, whiteness, total color difference (Delta "E"), and delta chromaticity (Delta "C") are also calculated. A single report or a group format is available. A PHOTOVOLT "T" or "Y" search unit must be used and each unit must be equipped with tristimulus filters to measure amber, blue, and green percent reflectance. This template is available as a free download from our web site at this URL: http://www.photovolt.com/pages/ss577.html

The formulas used for these calculations are shown below. In each case the A, B, and G values are the percent readings from the reflectometer from 00.0 to 99.9. CIE - X,Y,Z Scale per ASTM D 2244 X=0.80A+0.18B Y=1.00G Z=1.18B CIE - x, y, z Scale per ASTM D 2244 x = X/(X+Y+Z) y = Y/(X+Y+Z) z = 1- (x+y) L*a*b* (CIE 1976) per ASTM D 2244 L* = 116 (Y/100)^1/3 - 16 a* = 500 ((X/100)^1/3 - (Y/100)^1/3) b* = 200 ((Y/100) ^1/3 - (Z/100)^1/3) L* = 116 (Y/100) ^1/3 - 16 u = 4X/(X + 15Y + 3Z) v = 9Y/(X + 15Y + 3Z) Simplified NBS Equation per ASTM D 2244 L = 10 Y^ a = (17.5 (1.02 X-Y)) / Y^ b = (7.0 (Y - 0.847 Z)) / Y^ Yellowness Index YI = 100 (A - B) / G ASTM E 313 YI = 128X - 106Z / Y ASTM D 1925 YI = 100 (1 - 0.847 Z / Y) ASTM E 313 Whiteness Index per ASTM E 313 WI = 4 B - 3 G Delta Values per ASTM D 2244 dE of L*a*b** =((L1*-L2*)^2+(a1*-a2*)^2+(b1*-b2*)^2)^ dE of L a b = ((L1-L2)^2+(a1-a2)^2+(b1-b2)^2)^ dC of a* b* = ((a1*-a2*)^2+(b1*-b2*)^2)^ dC of a b = ((a1-a2)^2+(b1-b2)^2)^


D

Appendix D - 577PC-S

Figure 17. 577PC-S Stainless Steel Model The Photovolt Model 577A reflectometer is available with the SS stainless steel case option. This model has a shallow case with all controls and common connections on the front side. This allows mounting on a wall or shelf above and away from the work area. The case and search unit are made from stainless steel and sealed to a NEMA-4 splash proof rating. An extra long search unit coiled cable is included so samples up to ten feet away can be easily measured. The operation of the 577PC-S is identical to the standard instrument and all previous sections of this manual apply to this model equally.


E

This document contains information for use by owners and operators of the Photovolt Instruments Model 577PC Reflectometer. Information in this document is subject to change without notice. This document is considered proprietary and no part may be reproduced or transmitted in any form or by any means, electronic or mechanical, for any purpose, without the express prior written consent of Photovolt Instruments. If copies are then permitted, they must contain this proprietary notice. 2012 Photovolt Instruments. All rights reserved.

Photovolt Instruments

P/N: 9957710P Rev A

photovolt model 577pc reflectometer user’s manual

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