design project lab

List of Mini projects (for the Academic year 2015- 2016)

S. No Title of the Project

1 Design of temperature transducer using 3 wire RTD

2Configure the Variable Frequency Drive to jump the motor’s initial RPM to desired

RPM using Programmable Logic Controller

3Developing documentation report for the centre of excellence for industrial automation

laboratory

4 Design of PID controller using operational amplifier for an single tank level system

5 Design of instrumentation amplifier for a sensor

6Design of PI and PID controller using operational amplifier for a motor and compare

the controller performance

7 Design an inverted pendulum

8

A level control valve is to be installed on an 8” oil line going from an oil water

separator to an oil heater. The oil water separator operates at 3.5 barg and 250C. Inlet

pressure requirement at the heater is 2.0 barg. Normal, minimum and maximum oil

flow rates are 200m3/hr, 60m3/hr and 220 m3/hr respectively. Size a level control valve

to determine the control valve flow coefficient or valve Cv.

9Design a control panel which controls the speed of the exhaust fan based on the

temperature

10 Configure the HMI to control the 3 Tank conical tank system with PLC

1

Aim

To design piping and instrumentation diagram for the given process.

Apparatus Required

S.No Apparatus Quantity1. Process Station 12. Pencil 13. Scale 14. A3 Sheet 15. Procircle 1

Prerequisite Questions

1. Point out the need for Process Diagram.2 Mention the 2 types of control loops.3 List out the 6 types of signal used in automation.4 Specify 4 the types of sensors and actuators used in industries.

Theory

The P&ID refers to the detailed drawing of plant layout that includes pictorial representation of entire piping and instrumentation blocks used in a plant. It has been standardized by American National Standards Institute (ANSI) and Instrument Society of America (ISA). Equivalent Indian Standard is also available, e.g. “ IEC/PAS 62424 Ed. 1.0 en - Representation of process control engineering requests in P&I diagrams and data exchange between P&ID tools and PCE-CAE tools ”.

It describes and specifies how process control engineering requests are represented in a P&I diagram. It also defines the exchange of process control engineering request relevant data between a process control engineering tool and a P&I tool by means of a data transfer language (called CAEX). These provisions apply to the export/import applications of such tools. Following are the components of P&ID:

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Ex.No:1 DESIGN OF PIPING AND INSTRUMENTATION DIAGRAMDate :

Figure1.1 P&I Symbol for Valve

Table 1.Pre-defined format to Tag the Field Instruments

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Following are the components of P&ID:

Plant equipment and vessels showing location, capacity, pressure, liquid level operating range, usage and so on

All interconnection lines distinguishing between the types of interconnection, i.e. gas or electrical and operating range of line

All motors giving voltage and power and other relevant information Instrumentation showing location of instrument, its major function, process control loop

number, and range Control valves giving type of control, type of valve, type of valve action, fail save

features, and flow plus pressure information The ranges for all safety valves, pressure regulators, temperatures, and operating ranges All sensing devices, recorders, and transmitters with control loop numbers

The first letter indicates the property measured; for example, F = flow. Subsequent letters indicate the function; for example,

I = indicatingRC = recorder controller

The suffixes E and A can be added to indicate emergency action and/or alarm functions.

The instrument connecting lines should be drawn in a manner to distinguish them from the main process lines. Dotted or cross-hatched lines are normally used.

Procedure

First list out the types of instruments used in the process Identify the control loop type involved in the process List out the type of signal lines used in the process Draw piping and instrumentation diagram for the given process station using standard

symbols

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Figure 1.2 P&I diagram for Continuous Stirred Tank Reactor

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Viva Questions

1 List out the items in Piping and Instrumentation diagram.

2 Why do we need tag number in Piping and Instrumentation diagram?

3 Mention the criteria to define a tag number for an instrument.

4 Point out the types of valve used for specific process

5 List the abbreviation to mention different types of field instruments while giving tag number in P&ID diagram

6 Specify the organization who standardize the Piping and Instrumentation symbols

7 How will you interpret the information from a Piping and Instrumentation diagram?

8 Compare Piping and Instrumentation diagram & Process flow diagram.

9 Point out the types of display used to project the process parameters.

10 Mention the applications of P&I diagram in industries

Stimulating Questions

1 What are all information you infer from a pie chart, bar chart and XY plot? (M)

2 Infer the details such as type & specifications of components, flow direction of signals and from below Figure 1.3. (S)

Figure 1.3Result

Thus Piping and Instrumentation diagram for given process was drawn.

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Figure 2.1 Specification of Delta PLC (DVP 10SX)

Figure 2.2 Circuit diagram of electrical relay

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Aim

To design control panel wiring for a given system.

Apparatus Required

S.No Apparatus Quantity1 Delta PLC (DVP10SX) 1 No2 Relay Box 1 No3 Push Button 1 No4 Patch cards & wiring Few


1 Mention the 4 major components in programmable logic controller2 Explain the operation of relay.3 Why we need to ground the wire?4 How will you convert 230V AC to 24V DC?5 Compare PNP and NPN transistor.

Theory

Control panel wiring process involves providing power supply for the controller and input/output devices & connecting the input/output to the controller depending upon the types of instruments.

Connection of input/output device to PLC is of two different types viz., Sourcing and Sinking. Sourcing and Sinking terms refer to the manner in which DC devices are interfaced with the PLC. For a PLC input unit with sourcing, it is the source of the current supply for the input device connected to it. With sinking, the input device provides the current to the input unit.

Input / Output devices connected either in “Normally Open” connection or in “Normally Closed” connection subjected to application. Output devices always connected to PLC through Relay.

While designing wiring we also have to consider protection relay required for the system when we connect high voltage rated output devices connected to the PLC.

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Ex.No:2CONTROL PANEL WIRINGDate :

Figure 2.3 PLC interface with field instruments (Source type)

Table 2.1 Status output corresponding to input status

S.No Input Device Status Output Device Status1 NC push button ON Motor OFF2 NO push button ON Motor ON3 Latching input ON Motor ON4 Unlatch input ON Motor OFF

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Before wiring the instruments, following parameters to be noted,

Power supply Max/Min of the devices Current rating Max/Min of the devices Number of NO (Normally Open) contacts and NC contacts Number of relays required Number of SMPS required

Procedure

Connect the power supply pin of DELTA PLC (DVP10SX) to SMPS terminal Connect the RS232 terminal of PLC to the personal computer Connect the Input / Output devices in sinking or sourcing mode to the PLC Push the a knob in a PLC to STOP Mode In computer, go to COMMGR, Click -> ADD. Then type

o Station Address : “0”o Click “Auto Detect’”.o If the connection established between PLC and computer, it will show “Detection

Successful” Then go to WPLSOFT, Click File -> New -> Project Pop window show,

o Project Title : “Any name” o Type : “SX”o Then click “OK”

Ladder Logic window will open, in that type a ladder logic and save the file Then go to Compiler -> “Ladder => Instruction”, if there is error, clear the error. Then click the icon “Write to PLC” Now push the knob to RUN mode Then in hardware, turn on the input and observe whether Output turn on as per the ladder

instruction.

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Viva Question

1 Compare sourcing and sinking type of connection in PLC.

2 Differentiate PNP type sensor and NPN type sensor.

3 Is sourcing and sinking only available in PLC control panel wiring? Validate your statement

4 Classify the types of push buttons.

5 Compare Latch and unlatch concept.

6 Why we need relay while connecting load to the output module of the PLC?

7 How will you select amp rating of a MCB / Relay / Fuse?

8 What is the purpose of emergency push buttons in control panel wiring?

9 Specify the criteria to select PLC.

1

0

State the purpose of curve fitting.


1 How will you connect two way switch for a stair case light? (T)

2 How will wire a stop and start switch for pump used in home? (T)

Result

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Thus control panel wiring for PLC was done and verified.

Block Diagram

Figure 3.1 General Block diagram of proposed system

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Ex.No:3 SPEED CONTROL OF MOTOR PUMP USING VARIABLE FREQUENCY DRIVE(VFD)Date :

Aim

To control the speed of the given motor by using Variable Frequency Drive (VFD) through Programmable Logic Controller (PLC).

Apparatus Required

S.No Apparatus Quantity1 Spherical tank system 1 No2 VFD 1 No3 PLC (AB: Micrologix 1200) 1 No


1 Mention the 4 types of sensor used to measure the speed of the sensor.2 How motor pump operate?3 How programmable logic controller control the continuous process?4 Point out the specific speed control devices.5 How PID controller works?

Theory

The AC induction motor is a relatively simple, inexpensive, and rugged device which requires little maintenance. However, the induction motor is virtually a fixed speed device when operated from a constant frequency source. Since some applications require a fairly wide range of operating speeds, DC machines were often required. With the advent of power electronics, devices have become available that allow induction machines to be operated over a range of speeds. It is now frequently possible to buy an induction machine with an electronic drive for about the same price as a comparable DC machine. Furthermore, variable speed induction motors can also be used to drive pumps or fans more economically than the mechanical means which are often used to provide variable flow.

The upper limit on speed (ns) for an induction machine is determined by the frequency (f) of the applied voltage and the number of poles (P) on the motor:

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Figure 3.2 Ladder logic program for speed control of motor pump

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Thus for 60 Hz operation, a 2 pole motor can go no faster than 3600 rpm. As load is added to the shaft of an induction motor, the machine slows slightly and develops torque. The difference between the machine speed and synchronous speed is called slip.

The general purpose induction motor (Class B) may be expected to operate with a slip of about 2 or 3% at full load. Thus the motor would run at 3492 to 3528 rpm. In order to change this operating speed we must change the frequency of the applied voltage. Again considering the 2 pole motor, if the frequency were changed to 30 Hz, the motor would run somewhere around 1750 rpm while at 120 Hz it would run at approximately 7000 rpm.

Variable Frequency Drive

A variable-frequency drive (VFD) (also termed adjustable frequency drive, variable-speed drive, AC drive, micro drive or inverter drive) is a type of adjustable-speed drive used in electromechanical drive systems to control AC motor speed and torque by varying motor input frequency and voltage.

The operator interface provides a means for an operator to start and stop the motor and adjust the operating speed. Additional operator control functions might include reversing, and switching between manual speed adjustment and automatic control from an external process control signal. The operator interface often includes an alphanumeric display and/or indication lights and meters to provide information about the operation of the drive.

An operator interface keypad and display unit is often provided on the front of the VFD controller. The keypad display can often be cable-connected and mounted a short distance from the VFD controller. Most are also provided with input and output (I/O) terminals for connecting pushbuttons, switches and other operator interface devices or control signals. A serial communications port is also often available to allow the VFD to be configured, adjusted, monitored and controlled using a computer.

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Procedure

Confirm that all inputs are connected to the correct terminals and are secure.

Verify that any digital control power is 24 volts.

Verify that the Stop input is present or the drive will not start. Apply AC power and control voltages to the drive.

Configure the PLC using ladder logic programming method

Download the program to the PLC and provide set point to the controller.

Verify the process variable reaches the set point

Procedure to download ladder logic to PLC

230V power supply is given to the PLC as activation power supply.

The green colored knob is turned to switch on the PLC.

RS232 cable is connected between the PC and PLC.

Switch on the PC.

Establish the communication between the PC and PLC.(start-->program-->Rockwell software-->RSlinx-->RSlinx classic ->RSLogix classic Lite will open , in the menu bar->Communications-> configure diver(If something (running) is there under Nmae and Description/ status then click on that -> stop-> delete. Then go to Available Driver type and click on the arrow -> select RS-232 DF1 Devices-> Add new (A new window callled Add new RSLogix classic driver will open with AB_DF1-1) -> Ok. then (A new window called Configure RS-232 Devices will open) Auto-configure-> It sholud indicate with Auto Configuration successful --> Ok -->minimise or close the window)

New file is opened (start-->program-->Rockwell software-->RS logix micro english-->RS logix micro english-->RS logix microstarter-->new-->micro logix 1200series C(1 or 2 comm ports)-->ok)

File--> save--> give your defined name --> save, windows with program name (e.g. LEVELCONTROL.RSS), and LAD2 will appear, in Program_name.RSS window, + project will appear --> click on the + controller will appear click on the + --> double click on IO Configuration --> I/O configuration window will open, in that window click on read IO Config than a window called read IO configuration from on line processor will open--> click on read IO Config. Now IO modules are displayed under the part# /description (1762-IF2OF2 Analog 2 Chan. Input, Analog 2 Chan. Output) 3 times (since we have 3 analog modules in our PLC)

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Double click on (1762-IF2OF2 Analog 2 Chan. Input, Analog 2 Chan. Output)--> a window will open with name called module #1 1762-IF2OF2 Analog 2 Chan. Input, Analog 2 Chan. Output-->click on analog configuration-->in which all the four input ranges are changed to 4 to 20 mA and all the 4 data formats are changed to Raw/Promotional->ok . Similarly the remaining analog modules are configured 4 to 20 mA. I/O configuration window is closed.

The program is written for the given application using open contact (menu bar-user), closed contact(menu bar-user), output or relay coil (menu bar-user), memory bits (menu bar-Bit) timer(menu bar-timer/counter), counter(menu bar-timer/counter), scale with parameters-SCP(menu bar-Advanced math),PID(menu bar-File/Misc) and/or other parameters available in the menu bar.

The transmitter output (4 to 20 mA) must be compatible to the processor (6553 (for 4 mA) to 32787 (for 20mA)), since the processor resolution is 215 = 32768. Any data given to PID controller of PLC should be compatible to PID. Convert all PID inputs Process Variable, Set point in to 0 to 16383 (since the processor resolution is 214 = 16384) and PID output also will be in the rage of 0 to 16383 since this output must be rooted field through PLC processor/ Output module and the output should converted to 6553 to 32787 and again 4 to 20 mA. These conversions are done through 4 different SCP (Scale with parameters) blocks.

First SCP Parameters and Values Input: I:1.0 (Analog input: First module.0th channel)Process Variable

(PV), 4 to 20 mA from transmitter. Input Min: 6553 –> PV=4 mA Input Max.: 32787 -> PV= 20 mA Scaled Min.: 0 -> convert the 6553 to zero i.e. numeric value (Minimum

PV(Level)) Scaled Max.:59 convert the 32676 to 59 i.e. numeric value (maximum

PV(Maximum Level of the tank Output -> F8:0-> float variable, (Converted result(0 to 59) will be stored

in F8:0) Second SCP block Parameters and Values

Input: F8:0 (It has the Process variable (0 to 59 CM). Input Min:0 –> PV or Level minimum, Input Max.: 59 -> PV or Level maximum Scaled Min.: 0 -> convert the level minimum to zero (Conversion to PID

compatibility) Scaled Max.: 16383 convert the level maximum(59 CM) to 16383

(Conversion to PID compatibility) Output -> N7:0-> Integer variable, (Converted result(0 to 16383) will be

stored inN7:0) N7:0 will be assigned to PID block Process variable.

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Third SCP block Parameters and Values

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Input: N7:1 (Integer variable to load/give setpoint) Input Min:0 –> Setpoint (SP) minimum =0 CM Input Max.: 59 -> Setpoint maximum =59 CM Scaled Min.: 0 -> convert the SP minimum to zero (Conversion to PID

compatibility) Scaled Max.: 16383 convert the SP maximum(59 CM) to 16383

(Conversion to PID compatibility) Output -> PD9:0.SPS (PID name: 0th PID.Scaled set point) assignment of

converted SP value to PID block Setpoint.

The PID stores its output/Controlled Variable(CV), 0 to 16383 in N7:2 (Integer variable) Fourth SCP block Parameters and Values

Input: N7:2 CV from PID (N7:2 may be moved to F8:2 and it can be given here)

Input Min: 0 –> CV minimum Input Max.: 16383 -> CV Maximum Scaled Min.: 6553 (Conversion to Processor/Output module compatibility)

Scaled Max.:32762 (Conversion to Processor/Output module compatibility)

Output -> O:1.0 (Analog Output: First module.0th channel) CV to Actuator, 4 to 20 mA.

Program is compiled (menu bar-) edit -> Verify projects), if any errors are there, then the errors are corrected and project is verified again.

Program is downloaded to PLC(menu bar->Comms->Download--->)ok->yes-->yes-->changed yes--> due you want to go on line yes-yes

Transmitter output is connected to analog input module and output from the AO module is connected to the actuators.

The plant is switched on and the set value and actual value are compared.

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Viva Questions

1 What is pulse width modulation?2 Specify the components in Variable Frequency Drive (VFD).3 What are the functions can be carried out using VFD?4 How will change the ON duty and OFF duty time of PWM to control the speed of the

motor?5 How VFD controls the speed of the AC motor?6 Why do we want to scale the input and output in the PLC ladder logic program?7 Specify the hardware specifications of the PLC used in this experiment.8 Compare Analog output module and Digital output module in PLC.9 Compare the PLC and Microcontroller10 Why do we need PID controller instead of two position controller?


1 Why can’t we use a DC motor speed control circuit to an AC motor? (E)2 What happens to the speed of an AC motor when you change the load? (E)

Result

Thus the speed control of motor is controlled using Variable Frequency Drive was

verified.

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Figure 4.1 Connecting RTD to instrumentation amplifier through Wheatstone bridge

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Ex.No:4DESIGN OF INSTRUMENTATION AMPLIFIERDate:

Aim

To design a instrumentation amplifier for a Resistive Temperature Detector

Apparatus Required

S.No Apparatus Quantity1 RTD (PT 100) 1 No2 Op-amp (741) 3 Nos3 Resistor 100 ohm – 1 No

2 k ohm – 2 Nos1 k ohm – 1 No

4 Heating kettle 1 No5 Mercury Thermometer 1 No6 Dual voltage source 2 Nos


1 Specify the pin and its corresponding functions in operational amplifier 741.2 List out the 3 different types of amplifier used in industries.3 How a Wheatstone bridge operates?4 Mention the 5 types of temperature sensors used in industries.5 How will you predict the output voltage of the Wheatstone bridge?

Theory

Resistance temperature devices (RTD) are either a metal film deposited on a former or are wire-wound resistors. The devices are then sealed in a glass ceramic composite material. The electrical resistance of pure metals is positive, increasing linearly with temperature.

Resistive Temperature Detectors (RTDs) relate resistance to temperature by the following formula:

RT 2=R ref (1+α [T−T ref ])Where,RT = Resistance of R TD at given temperature T (ohms)Rref = Resistance of R TD at the reference temperature Tref (ohms)α = Temperature co-efficient of resistance (ohms per ohm/degree)

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Table 4.1 Output value obtained from the instrumentation amplifier for corresponding temperature

S.No Temperature in degree Celsius Voltage in V1. 100 102. 80 9.63. 90 9.24. 70 8.85. 60 8.46. 50 87. 40 7.68. 32 7.2

Graph: (Temperature Vs Voltage)

20 30 40 50 60 70 80 90 100 1100

2

4

6

8

10

12

Voltage in V

Temperature in Deg Celcius

Volta

ge in

V

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Instrumentation Amplifier

In a number of industrial and consumer applications, one is required to measure and control physical quantities. Some typical examples are measurement and control of temperature ,humidity, light intensity, water flow etc. These physical quantities are usually measured with the help of transducers. The output of transducer has to be amplified so that it can drive the indicator or display system. This function is performed by an Instrumentation Amplifier. The important features of Instrumentation Amplifier are

(i) High gain accuracy(ii) High CMRR(iii) High gain stability with low temperature coefficient(iv) Low dc offset

Monolithic (single chip ) Instrumentation Amplifier are also available commercially such as AD521,AD 524, AD 620, AD624 by Analog devices, LM 363.XX(xx—10,100,500) by National semiconductor and INA 101,104,3626,3629 by Burr-Brown.There are a number of practical applications of Instrumentation Amplifier with transducer bridge ,such as a temperature indicator, temperature controller, light intensity meter etc

Op-amps A1 and A2 have differential voltage as zero. For V1 = V2 ,that is, under common mode condition , the voltage across R will be zero. As no current flows through R and R’ the non inverting amplifier A1 act as voltage follower, so its output V2’ = V2. Similarly op-amp A2 act as voltage follower having output V1’ = V1.However if V1 ≠ V2≠ ,current flows in R and R’ and (V2‘ - V 1’) > (V2 - V 1 ).Therefore this circuit has more differential gain and CMRR.

The Output voltage V0 can be calculated as follows:

The voltage at the +ve input terminal of opamp A3 is (R2 / (R1+R2)) V1’

Using superposition theorem ,we have,

Vo = (-R2/ R1) V2‘ + (1+ ( R2/ R1) (R2 V 1’/(R1+R2))

Vo = R2/ R1 (V1‘ - V 2’) -----------(1)

Since no current flows into Op-amp, the current I flowing (upwards) in R is,I = (V1 - V 2 )./R and pass through the resistor R’.

V1‘ = R’ I + V1 = R’ /R (V1 - V 2 ) +V1 and V2‘ = - R’ I + V2 = -R’ /R (V1 - V 2 ) +V2

Putting the values of V1‘ and V 2’ in eq (1) ,we obtain

Vo = R2/ R1[ R’ /R (V1 - V 2 ) +V1+ R’ /R (V1 - V 2 ) +V2]

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Vo = R2/ R1[ 2 R’ /R (V1 - V 2 ) + (V1 - V 2 ) ]

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Vo = (R2/ R1 )(1+ 2 R’ /R ) (V1 - V 2 )

Procedure

Connect the Two wire RTD (PT 100) to wheatstone bridge and connect the wheatstone

bridge output with instrumentation amplifier circuit as shown in the circuit diagram.

Dip the RTD in the water heating kettle, note the water temperature using thermometer.

Note the corresponding output voltage of instrumentation amplifier for the current

temperature

Repeat the experiment for 10 different temperatures

Plot the graph between temperature and voltage

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Viva Questions

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1 Compare ideal op-amp and practical op-amp.2 What is the purpose eof offset pin in op-amp?3 Why do we need wheatstone bridge to connect RTD with instrumentation amplifier?4 What is the meaning behind RTD –PT 100?5 How will you find the resistance value in the instrumentation amplifier for desired output

voltage for the given application?6 Mention the 3 stages in instrumentation amplifier.7 What is mean by unity gain instrumentation amplifier?8 List any 3 different types of units available for temperature.9 Why do we select range of 1-5V as sensor output in industries?10

Compare instrumentation amplifier with other amplifiers.


1 What haapens if you transmit milli voltage for a long distance?2 How will you measure the poutput variations of the sensor without amplifier?

Result

Thus the instrumentation was designed for RTD and verified.

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Table 5.1 Bill of materials

S.No Instrument Type Range Quantity

1 RTD PT-100 0 – 100 deg celcius

4

2 Flow sensor Differential Pressure 0 – 1500 LPH 1

3 Level sensor Differential Pressure 0 – 60 CM 1

4 Current to Pressure Converter

Spring balance type 4 – 20 mA /3 – 15 PSI

1

5 SCR power controller for heating coil

SCR 4 – 20 mA /0 – 230 V

1

6 Pneumatic Control valve

Linear 3 – 15 PSI /0% - 100%

1

7 Relay MCB A , A 1, 4

8 Display panel LED display --- 8

9 Pump -- --- 1

10 Motor --- --- 1

11 Local flow meter Rotameter 0 --- 1500 LPH 1

12 Hand Valve Ball type --- 6

13 Light Indicator --- --- 1

Table 5.2 Instrument I/O ListS.No

TAG No

Controller TAG UNIT Instrument Remark

AI

AO

DI DO

1 FTIN01 FTIN01 CSTR FLOW INDICATOR / TRANSMITTER 1

2 LT01 LT01 CSTR LEVEL INDICATOR / TRANSMITTER 1

3 TIN01 TIN01 CSTR TEMPERATURE INDICATOR 1

4TIN02 TIN02

CSTRTEMPERATURE INDICATOR / TRANSMITTER

1

5TOUT01 TOUT01

CSTRTEMPERATURE INDICATOR

1

6TOUT02 TOUT02

CSTRTEMPERATURE INDICATOR

1

7 CV01 CV01 CSTR INPUT FLOW CONTROL VALVE 1

8SCR01 SCR01

CSTRHEATING COIL INDICATOR / CONTROLLER

1

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EX.No:5 PREPARATION OF DOCUMENTATION OF INSTRUMENTATION PROJECT AND PROJECT SCHEDULING FOR THE GIVEN CASE STUDY

Date :

AimTo prepare documentation report for the given case study

S.No Apparatus Quantity1 Process Station 1 No2 Pencil, Scale, Eraser and Pro circle 1 No3 Scale 1 No4 A3 Sheets 1 No


1 Point out the need of equipment’s specification listed in all equipment.2 List out the organizations responsible for standardizing the documentation format.3 Mention the 4 types of flow meters used in industrial applications.4 List out the 4 types of flow sensor used in industrial applications.5 Specify the types of valve used in industrial applications.

DescriptionThe preparation of documentation of Instrumentation project comprises preparation of

specifications and data sheets, preparation of drawings and process flow diagram , Instrument index and sheet, specification sheet.Preparation of Specifications and Datasheets For a specific project document, the following shall be indicated on each page of the

document:

-Left footer:The project number of the related project shall be shown in the left footer, followed by the document number and the revision number.Example: A30028/701 Rev. 1

-Right footer:The right footer shall show the number of the page as part of the total document.Example: 1 of 15

-Datasheets:Company's standard datasheets shall be applied for the specification of the requiredinstrumentation.Each datasheet, not part of a specification, shall be provided with a standard coversheet.

To avoid contradiction of information, the information on the documents to be preparedshall not have unnecessary duplication.

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Table 5.3 Loop Schematics

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Guidelines for Preparation of Drawings Drawings shall be made in accordance with Company standard practice with regard to:

* formats* style* contents* numbering system* lay-out and title block* symbols* terminology* line thickness* revision system* platform north direction.

In case the Company's standards are not available, the new drawings shall be prepared inconjunction with the discipline engineer of the Company.

CAD drafting shall be done in such a way that A3 or A4 copies are clearly legible and reproducible.

"Original" drawings and "Master" drawings shall be identified as such, e.g. by rubber stamp or original (blue) signatures.

To avoid contradiction of information, the information on the drawings to be prepared shall not have unnecessary duplication.

Contents of Drawings

All drawings shall be made in the English language. All dimensions, co-ordinates and elevations shall be given in millimeters. Pipe sizes shall be given in inches Nominal Diameter. All texts shall be legible from the bottom or right-hand side of the drawing. The scale of the drawing shall be shown in the title block. If part of the drawing is not to

scale the words "NOT TO SCALE" shall be clearly shown.

Guidelines for Preparation of Process Flow Diagram- Instrumentation System

The P&ID's shall be according to the general engineering practice and the following generalphilosophy:

All data on P&ID's shall be drawn in a logical sequence and grouped such that each sheet contains as much data as possible while clearly legible on A3 size sheets.

The symbols, abbreviations and line numbers shall be shown in accordance with the legend sheet of the P&ID.

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Figure 5.1 Piping and Instrumentation diagram

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All mechanical items shall be drawn schematically and indicated by tag numbers and a short description in the heading.

All piping shall be shown including line numbers, Specification breaks, valves with tag numbers, flanges, special item symbols and numbers, insulation and references to adjacent sheets. Remarks not covered by the standard symbolism shall be shown as notes in the title block. The functionality of all instruments on the P&ID shall be shown clearly and logically.

For an instrumentation loop, the P&ID shall show the total loop schematically without the auxiliary devices (e.g. from transmitter via a controller to a control valve; the auxiliary devices such as the power supply unit, isolators, barriers shall not be shown on the P&ID).

Each instrument shall be provided with a unique tag number and each loop shall have identical numerical tag (loop) number.When several units generate a common (multi-function) alarm, the tag number of this alarm shall be "XA-" followed by the lowest numerical tag number of the units.Example: Three generators, with the tag numbers G-801, G-802 and G-803, generate a common alarm "XA-801".

All peripheral in-line instrument devices such as flow element, temperature sensor, thermo well shall be shown on the P&ID. The connection size and type of the thermo well shall also be indicated.

When a local control panel is present, this panel shall be indicated as a square box. This square box shall contain as a minimum the following description:tag number of the local control panelreference description to detail drawing of the local control panel.Input/output signals interfaces between this local control panel and other instrument devices shall be shown clearly on the P&ID.

All types of signal transmission (hydraulic, electric and pneumatic) shall be shown clearly according to the legend sheet.

When a signal conversion has occurred (e.g. from pneumatic to electric), the signal converter (receiving switches, I/P converter etc.) shall be indicated on the P&ID.

The fail position of the valves shall be indicated on the P&ID by using an "upwards" (fail open) or "downwards" (fail closed) arrow on the valve's symbolism.

A multi-position selector switch shall be shown for a parallel control strategy configuration. In this case a control signal is split to several devices and by selection only one device can be operated at the time.

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Example: stand-by/duty selector switch for two injection pumps whereby only one pump can running at the same time.

A manual operated device (e.g. pull/push button, hand switch) for operation of a dedicated system, shall be indicated on the P&ID.

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Viva Questions

1 List out the 4 items in Piping and Instrumentation diagram.

2 Why do we need tag number in Piping and Instrumentation diagram?

3 Mention the criteria to define a tag number for an instrument.

4 Point out the details to be entered in bill of materials .

5 What are all the information are to be inferred from loop schematics?

6 Specify the organization who standardize the Piping and Instrumentation symbols.

7 Why we need to mention the I/O list in the documentation?

8 Compare Piping and Instrumentation diagram & Process flow diagram.

9 Point out the types of display used to project the process parameters.

10 Mention the applications of P&I diagram in industries.


1 Find out the specifications of sensor / actuator which don’t have any specification plate on it. (E)

2 Infer the open loop, closed loop, I/O details from a documentation report.(E)

Result

Thus the project documentation was prepared for the given case study.

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Figure 6.1 HMI interfacing with PLC and Personal computer

Figure 6.2 Configuration screen of Panel View C600 HMI

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Ex.No:6CONFIGURING HUMAN MACHINE INTERFACE (HMI)Date :

Aim

To configure HMI for the given Programmable Logic Controller (PLC) based application

Apparatus Required

S.No Apparatus Quantity1 HMI (AB-Panel View

C600)1 No

2 AB PLC : Micrologix 1200

1 No

3 Patch cards As required4 Ethernet Cable 1 No5 Wires As required

Prerequisite Question

1 Point out the function of PLC.2 List the 5 data types used in PLC.3 Specify the communication cable used to interface PLC and computer.4 Mention the three functions of PLC.5 Specify the function of analog module and digital module.

Theory

In complex systems, the human–machine interface is typically computerized. The term human–computer interface refers to this kind of system. The engineering of the human–machine interfaces is by considering ergonomics (Human Factors). The corresponding disciplines are Human Factors Engineering (HFE) and Usability Engineering (UE), which is part of Systems Engineering.

A Human Machine Interface (HMI) is exactly what the name implies; a graphical interface that allows humans and machines to interact. Human machine interfaces vary widely, from control panels for nuclear power plants, to the screen on an iPhone. However, for this discussion we are referring to an HMI control panel for manufacturing-type processes. An HMI is the centralized control unit for manufacturing lines, equipped with Data Recipes, event logging, video feed, and event triggering, so that one may access the system at any moment for any purpose.

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Figure 6.4 HMI program in Panel View C600

Table 6.1 Status output corresponding to input status

S.No Input Device Status Output Device Status1 NC push button ON Motor OFF2 NO push button ON Motor ON3 Latching input ON Motor ON4 Unlatch input ON Motor OFF

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For a manufacturing line to be integrated with an HMI, it must first be working with a Programmable Logic Controller (PLC). It is the PLC that takes the information from the sensors, and transforms it to Boolean algebra, so the HMI can decipher and make decisions.

There are three basic types of HMIs: the pushbutton replacer, the data handler, and the overseer. Before the HMI came into existence, a control might consist of hundreds of pushbuttons and LEDs performing different operations. The pushbutton replacer HMI has streamlined manufacturing processes, centralizing all the functions of each button into one location.

The data handler is perfect for applications requiring constant feedback from the system, or printouts of the production reports. With the data handler, you must ensure the HMI screen is big enough for such things as graphs, visual representations and production summaries. The data handler includes such functions as recipes, data trending, data logging and alarm handling/logging. Finally, anytime an application involves SCADA or MES, an overseer HMI is extremely beneficial. The overseer HMI will most likely need to run Windows, and have several Ethernet ports.

Procedure

Connect the power supply for the HMI

Connect the HMI to personal computer using Ethernet cable

Open internet explorer and type http://192.168.1.103 in URL

Program Micrologix PLC for the given application through RS232

Download the program to the PLC

Configure the HMI for your application as shown in Annexure II

Now connect the HMI to PLC through RS232 cable

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Viva Questions

1 Why do we need a device to communicate with a machine which is fully automated?

2 Specify the features of human machine interface.

3 Mention the communication ports available in human machine interface.

4 Point out the pre-caution to be taken before running the HMI program.

5 How will you interface HMI with PLC?

6 How the function modules in HMI are categorized?

7 How to tag your visual components with PLC I/O points?

8 Specify the advanced features of HMI used in industries.

9 Why we need to place GO TO configure button?

10 Compare HMI and control panel.

Stimulating questions

1 What are the I/O available in control panel? (T)2 How will you stop a latched output? (T)

Result

Thus HMI was successfully configured for the given PLC based application.

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Table 7.1 The valve chart for equal percentage valve

‘

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Ex.No:7DESIGN OF CONTROL VALVE SIZINGDate:

Aim

To design and select a control valve to meet the following specification.

The system is pumping water from one tank to another through a piping system with a total pressure drop of 150 psi. The fluid is water at 70 0F. Design (maximum) flowrate of 150 gpm, operating flowrate of 110 gpm, and a minimum flowrate of 25 gpm. The pipe diameter is 3 inches. At 70 0F, water has a specific gravity of 1.0.

Apparatus Required

S.No Apparatus Quantity1 Pneumatic valve setup 1 No2 Voltage Source 1 No3 Voltage to Current 1 No


1 Why do we need a control valve?2 What is an inherent characteristic of control valve?3 What is an installed characteristic of control valve?4 What is meant by discharge co-efficient?5 How a positioner works in a control valve?

Theory

Control valves consist of a plug on the end of a stem that opens or closes an orifice opening as the stem is raised and lowered. The stem is attached to a diaphragm that is driven by instrument air pressure. The typical range of air pressure is 3 to 15 psig. The control valve flow characteristic is defined as the relationship between the flow through the valve and the valve position as the position is varied from 0% open to 100% open.

There are two types of characteristics: inherent and installed flow characteristic. Inherent flow characteristic refers to the characteristic observed with constant pressure drop across the valve.

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Table 7.2 To determine the Cv value of the control valve

Gain #1 = 85/38 = 2.2, Gain #2 = 40/12 = 3.3

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Flow (gpm)

Stroke (%)Change in flow

(gpm)Change in Stroke (%)

25 35 110-25 = 85 73-35 = 38110 73150 85 150-110 = 40 85-73 = 12

Installed flow characteristic refers to the characteristic observed when the valve is in service with varying pressure drop and other changes in the system.

Control valves sizing calculator can be used to calculate maximum flow rate through control valve for given pressure drop and known flow coefficient of control valve Cv. From control valve sizing, we can determine the Maximum flow rate through control valve, Flow velocity, and Flow coefficient. To determine the discharge co-efficient of control valve following parameters are to be measured, Valve diameter, and Pressure drop Liquid density

Control valve sizing is based on the flow coefficient Cv calculation. Calculation of Cv is made for required flow rate and related pressure drop in control valve. With flow coefficient Cv calculated, size of control valve can be selected. Two control valves from different manufacturers can be compared in terms of flow capacity for certain pressure drop and the same control valve size comparing its Cv.

Cv calculation is based on the relation between pressure drop and flow rate in control valve which is for complete turbulent flow following power law where flow coefficient Cv is the proportional constant. Cv is determined experimentally by control valve manufacturers. Control valve Cv is expressed as the flow rate of water in gpm u.s. (m3/h) for a pressure drop of 1 psi (1 bar) across a flow passage (flow coefficient: Cv-imperial, Kv-metric).Control valve calculator can be used for turbulent flow of water or other incompressible fluid. For compressible flow of gases and steam gas flow coefficient Cg should be calculated.

Design ProcedureStep #1: Define the system The system is pumping water from one tank to another through a piping system with a total pressure drop of 150 psi. The fluid is water at 70 0F. Design (maximum) flowrate of 150 gpm, operating flowrate of 110 gpm, and a minimum flowrate of 25 gpm. The pipe diameter is 3 inches. At 70 0F, water has a specific gravity of 1.0.

Step #2: Define a maximum allowable pressure drop for the valve The system pressure drop is limited by the pump. Essentially the Net Positive Suction Head Available (NPSHA) minus the Net Positive Suction Head Required (NPSHR) is the maximum available pressure drop for the valve to use and this must not be exceeded or another pump will be needed. The usual rule of thumb is that a valve should be designed to use 10-15% of the total pressure drop or 10 psi, whichever is greater. For our system, 10% of the total pressure drop is 15 psi which is what we'll use as our allowable pressure drop when the valve is wide open (the pump is our system is easily capable of the additional pressure drop).

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Step #3: Calculate the valve characteristic

For our system,

Step #4: Preliminary valve selection The Cv value should be used as a guide in the valve selection, not a hard and fast rule. Some other considerations are:(i). Never use a valve that is less than half the pipe size(ii). Avoid using the lower 10% and upper 20% of the valve stroke. The valve is much easier to control in the 10-80% stroke range.

Before a valve can be selected, we have to decide what type of valve will be used For our case, we'll assume we're using an equal percentage, globe valve .With reference to the valve chart it appears that the 2 inch valve will work well for our Cv value at about 80-85% of the stroke range. Notice that we're not trying to squeeze our Cv into the 1 1/2 valve which would need to be at 100% stroke to handle our maximum flow. If this valve were used, two consequences would be experienced: the pressure drop would be a little higher than 15 psi at our design (max) flow and the valve would be difficult to control at maximum flow. Also, there would be no room for error with this valve, but the valve we've chosen will allow for flow surges beyond the 150 gpm range. So there are still some characteristics to consider.

Step #5: Check the Cv and stroke percentage at the minimum flow If the stroke percentage falls below 10% at our minimum flow, a smaller valve may have to be used in some cases. It's difficult to find whether the system more likely to operate closer to the maximum flow rates or minimum flow rate. Hence it is difficult to find the perfect value, but we should find one that operates well most of the time. Let's check the valve we've selected for our system:

Referring back to our valve chart, we see that a Cv of 6.5 would correspond to a stroke percentage of around 35-40% which is certainly acceptable. If our Cv at the minimum flow would have been around 1.5, there would not really be a problem because the valve has a Cv of 1.66 at 10% stroke and since we use the maximum pressure drop, our estimate is

55

conservative. Essentially, at lower pressure drops, Cv would only increase which in this case would be advantageous.

Step #6: Check the gain across applicable flow rates

Gain is defined as:

Now, at our three flowrates:Qmin = 25 gpmQop = 110 gpmQdes = 150 gpmwe have corresponding Cv values of 6.5, 28, and 39. The corresponding stroke percentages are 35%, 73%, and 85% respectively.

Note: The difference between these values should be less than 50% of the higher value.0.5 (3.3) = 1.65 and 3.3 - 2.2 = 1.10. Since 1.10 is less than 1.65, there should be no problem in controlling the valve. Also note that the gain should never be less than 0.50. So for our case, the selected valve will do nicely

57

Viva Questions

1 State the control valve sizing in own words2 State Cv in your own words.3 Why we need to perform control valve sizing?4 Mention three parameters can be determined using control valve sizing.5 List the three parameter to be measured to perform control valve sizing6 Compare control valve sizing and orifice plate sizing.7 Express the equation to find Cv value for gas?8 Point out the need to calculate Reynold number in control valve sizing9 Control valve sizing will reduce cavitation and flashing in control valve. Validate the

statement10 Specify the effects cavitation and flashing in control valve


1 What happens to control valve if we calculated the wrong Cv value for the valve?(E)2 What happens if pipe diameter changes after fitting control valve for specified Cv value?

(E)

Result

Thus the control valve sizing was done for given specification

59

Figure 8.1 Simulator for Orifice Plate

60

Ex.No:8 DESIGN AN ORIFICE PLATE FOR A TYPICAL APPLICATIONDate :

Aim

To design an orifice plate for a typical application.

Apparatus Required

S.No Apparatus Quantity1. Orifice setup 1 No


1 Describe the construction and principle of working of an orifice meter.2 What are the different types of orifice plate?3 List out advantages and disadvantages of orifice meter4 State and elaborate for what kind of application the orifice meter is a best choice5 What are the design guidelines of orifice meter?

Theory

Orifice meter is type of variable head meter. In this meter the obstruction to the flow consist of an engineering constriction in the metered fluid which causes a reduction in the flow pressure. An orifice meter is a conduit and a restriction to create a pressure drop. It uses the same principle as a Venturi nozzle, namely Bernoulli's principle which states that there is a relationship between the pressure of the fluid and the velocity of the fluid. When the velocity increases, the pressure decreases and vice versa.

An orifice plate is a thin plate with a hole in the center of the plate. It is usually placed in a pipe in such a way that fluid passed through the hole. When the fluid reaches the orifice plate, with the hole in the middle, the fluid is forced to converge to go through the small hole; the point of maximum convergence actually occurs shortly downstream of the physical orifice, at the so-called vena contracta.

Vena contracta is a point where the velocity and the pressure changes. Beyond the vena contracta, the fluid expands and the velocity and pressure change once again. By measuring the difference in fluid pressure between the normal pipe section and at the vena contracta, the volumetric and mass flow rates can be obtained from Bernoulli's equation. There are different

61

Specification

Process Fluid (Service): Water

Measurement Taps: Flange

Calibrated Flow range: 0 to 3100 lph

Differential Pressure Transmitter (DPT) range: 0 to 430 mmWC

DPT ouput: 4 to 20 mA

Supply Voltage: 24V

Pipe Diameter (ID), D: 40mm (NB)

Orifice Diameter, d: 22mm (NB)

Table 8.1 DPT output for corresponding flow in the pipe

FlowL/h

delta p mmWC

DPT Output

mA0 -0.875 3.9916 0 4

1000 46.5 5.681380 87.7 7.261770 137 9.092080 196 11.282380 265 13.832690 341 16.733080 424 19.8

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types of orifice plate that are namely Concentric, Segmental, And Eccentric and Quadrant Edge and Conic Edge.

In order to use any of these devices for measurement it is necessary to empirically calibrate them. That is, pass a known volume through the meter and note the reading in order to provide a standard for measuring other quantities. Due to the ease of duplicating and the simple construction, the thin sharp edged orifice has been adopted as a standard and extensive calibration work has been done so that it is widely accepted as a standard means of measuring fluids.

Provided the standard mechanics of construction are followed no further calibration is required. An orifice in a pipeline with a manometer for measuring the drop in pressure (differential) as the fluid passes through the orifice. The minimum cross sectional area of the jet is known as the “vena contracta” where the velocity is maximum and static pressure is minimum. It is observed at some distance from orifice because of inertia effects persisting in flow direction. Materials used for orifice plate are mild steel, stainless steel, phosphor bronze and gun metal.

Procedure

1. Study the diagram completely.

2. Select the value of beta ratio (β).

3. Select the value of orifice diameter (d) in meter.

4. Click on Done. This will lock the values of β and d.

5. Change the value of Volumetric Flow Rate in LPM (Q) by a cursor.

6. Click on Show Cd tab. The coefficient of discharge will be displayed.

7. Enter the calculated user output differential pressure. For calculations of differential pressure

∆P, click on GET FORMULA tab.

8. Using formula calculate the value of the differential pressure and enter the answer in the box

provided. Submit the answer using submit button.

9. If your calculation is correct the differential pressure will be displayed on screen. Change the

value of Q and repeat the steps 5 to 8.

10. Minimum six calculations are necessary to plot the graph and after six calculations the plot

tab will be activated.

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0 500 1000 1500 2000 2500 3000 35000

5

10

15

20

25

Flow vs DPT output

DPT Output mA

Flow in L/h

DPT

outp

ut in

mA

Figure 8.2 Graph plot between Flow vs DPT output

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Viva Questions

1 Mention the three types of orifice plate.2 Express the equation to determine the discharge co-efficient of orifice plate.3 Compare venturi and orifice.4 Compare orfice plate design and control valve sizing5 Specify the 3 types of pressure measuring device used in industries.6 Is it necessary to calculate temperature of the process liquid?7 Will change in density affects the calculation of discharge co-efficient of orifice plate?


1 What happens when we place venturi meter in the palce of orifice meter?(E)

Result

Thus orifice plate was designed for given specification and verified.

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Figure 9.1 RTD signal conditioning circuit

Figure 9.2 Components of temperature sensor

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Ex.No:9DESIGN OF TEMPERATURE TRANSDUCERDate:

Aim

To assemble a temperature transducer using given sensing element

Apparatus Required

S.No Apparatus Quantity1 RTD (PT 100) 1 No2 Op-amp (741) 1 No3 Resistor 100 ohm – 1 No

2 k ohm – 2 No1 k ohm – 1 No

4 NI DAQ 1 No5 Voltage source 1 No6 Computer 1 No


1 Specify the pin and its corresponding functions in operational amplifier 741.2 List out the different types of amplifier used in industries.3 How a Wheatstone bridge operates?4 Mention the types of temperature sensors.5 How will you predict the output voltage of the Wheatstone bridge?

Theory

Resistance temperature devices (RTD) are either a metal film deposited on a former or are wire-wound resistors. The devices are then sealed in a glass ceramic composite material. The electrical resistance of pure metals is positive, increasing linearly with temperature.

Resistive Temperature Detectors (RTDs) relate resistance to temperature by the following formula:

RT 2=Rref (1+α [T−T ref ])Where,RT = Resistance of R TD at given temperature T (ohms)Rref = Resistance of R TD at the reference temperature Tref (ohms)α = Temperature co-efficient of resistance (ohms per ohm/degree)

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Table 9.1 Temperature value and corresponding op-amp output voltage

S.No Temperature in degree Celsius Voltage in V1. 100 4.82. 80 4.63. 90 4.44. 70 4.25. 60 46. 50 3.97. 40 3.58. 32 3

20 30 40 50 60 70 80 90 100 1100

1

2

3

4

5

6

f(x) = 0.023354251261228 x + 2.52613510520487R² = 0.908327231430549

Chart Title

Series2Linear (Series2)

Temperature in Deg Celcius

Volta

ge in

V

Figure 9.3 Graph plot between Temperature Vs Voltage

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Curve fittingCurve fitting capturing the trend in the data by assigning a single function across the

entire range. There will be a dependent variable and an independent variable. Identifying the dependent and independent variables in a mathematical equation will help you identify what you are solving for in the equation. The independent variables are variable whose value determines the value of the dependent variables. Independent variable is plotted on the X-axis, and the dependent variable is plotted on the Y-axis. Other variables may also be present in equations. These may be constants or other variables. They may be given to you or you may be required to obtain them by performing curve fitting. The example below illustrates this point.

Equation 1: y = mx + C y = dependent variable x = independent variable m and C = constants

Procedure

Connect the Two wire RTD (PT 100) to wheatstone bridge and connect the wheatstone

bridge output with differential amplifier circuit as shown in the circuit diagram.

Dip the RTD in the water heating kettle, note the water temperature using thermometer.

Note the corresponding output voltage of differential amplifier for the current

temperature

Repeat the experiment for 10 different temperatures

Plot the graph between temperature and voltage in excel sheet and find out the linear

equation using curve fitting method

Connect differential amplifier to the NI – DAQ card

Create a program to get the output of differential amplifier and give it as input to the

equation found in curve fitting

The output of the equation directly shows the value of temperature of the measuring object in the front panel of the LABVIEW

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Figure 9.4 LabVIEW Block diagram

Figure 9.5 LabVIEW Front panel

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Viva Questions

1 Compare differential amplifier and instrumentation amplifier.2 What is the purpose of amplifier?3 Why do we need wheatstone bridge to connect RTD with instrumentation amplifier?4 What is the meaning behind RTD –PT 100?5 How will you find the resistance value in the instrumentation amplifier for desired output

voltage for the given application?6 Compare two wire and three wire RTD.7 What is mean by unity gain instrumentation amplifier?8 List the 3 different types of units available for temperature.9 Why do we select range of 1-5V as sensor output in industries?10

Why do we perform curve fitting?.


1 Conver the voltage of pressure sensor in to real time pressure value without using curve fitting.(M)

2 How will identify the parameter value when your sensor shows the value in voltage / current? (E)

Result

Thus the temperature sensor was assembled using given sensing element.

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Figure 10.1 Circuit diagram for PID controller using operational amplifier

Ex.No: 10DESIGN OF P, PI AND PID CONTROLLERDate:

Aim

To design P, PI and PID controller using operational amplifier

Apparatus Required

S.No Apparatus Quantity1 Dual Voltage source 2 Nos2 Bread Board 2 Nos3 Op-amp (741) As required4 Resistor As required5 Capacitor As required6 Multimeter 1 No


1 Mention the four parameters in closed loop system.2 State the process variable in your own words3 What is the input to the controller?4 Compare closed loop system and open loop system.5 Compare feedback and feedforward system.

Theory

A PID (Proportional Integral Derivative) controller is a common instrument used in industrial control applications. A PID controller can be used for regulation of speed, temperature, flow, pressure and other process variables. Field mounted PID controllers can be placed close to the sensor or the control regulation device and be monitored centrally using a SCADA system.

Proportional Response

The proportional component depends only on the difference between the set point and the process variable. This difference is referred to as the Error term. The proportional gain (Kc) determines the ratio of output response to the error signal. For instance, if the error term has a magnitude of 10, a proportional gain of 5 would produce a proportional response of 50. In general, increasing the proportional gain will increase the speed of the control system response. However, if the proportional gain is too large, the process variable will begin to oscillate. If Kc is

73

increased further, the oscillations will become larger and the system will become unstable and may even oscillate out of control.

Table 10.1 Output of the controller for corresponding change in process variable

S.No Condition Controller Output in V

1 Set point = Process Variable

2 Set point > Process Variable

3Set point < Process Variable

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Integral Response

The integral component sums the error term over time. The result is that even a small error term will cause the integral component to increase slowly. The integral response will continually increase over time unless the error is zero, so the effect is to drive the Steady-State error to zero. Steady-State error is the final difference between the process variable and set point. A phenomenon called integral windup results when integral action saturates a controller without the controller driving the error signal toward zero

Derivative Response

The derivative component causes the output to decrease if the process variable is increasing rapidly. The derivative response is proportional to the rate of change of the process variable. Increasing the derivative time (Td) parameter will cause the control system to react more strongly to changes in the error term and will increase the speed of the overall control system response. Most practical control systems use very small derivative time (Td), because the Derivative Response is highly sensitive to noise in the process variable signal. If the sensor feedback signal is noisy or if the control loop rate is too slow, the derivative response can make the control system unstable

Procedure

Connect the given components as given in circuit diagram

Set the set point of the PID controller.

Adjust the process variable so that it equals set point value and check whether controller output is zero in that situation.

Make the process variable value to zero and check whether controller output is maximum

Adjust the process variable to maximum and set point value to minimum; check whether controller output is maximum in that situation.

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Viva Question

1. Identify need for controller2. List the different types of controllers?3. State the function of P controller4. Represent the purpose of the I controller5. List the application D controller.6. Infer the need of PID controller in the controller system7. Define reset rate8. Point out the drawback of P controller9. Infer the advantage and disadvantage of integral controller10. Why derivative controller is not employed in isolation?11. Sketch the step response of P&PI controller12. Draw the ramp response of P, PI&PID controller13. Label the basic components of automatic control system14. Addition of I controller into p controller improves the performance. Justify

Stimulating Question

1. Realize a PID controller algorithm in pneumatic system. (T)2. How will you control the continuous process without PID? (E)

Result

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Thus PID controller using P, PI and PID were designed using operational amplifier and verified.

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design project lab

Documents

level control valve

type of control

control panel

design of pid controller

control valve flow coefficient

process diagram

types of control loops

process control loop