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SPEED CONTROL MODULE TRAINER

(Model No : VPAT - 10)

Technical Reference

Version 1.0

Technical Clarification /Suggestion :

N / F

Technical Support Division,

Vi Microsystems Pvt. Ltd.,Plot No :75,Electronics Estate,

Perungudi,Chennai - 600 096,INDIA.

Ph: 91- 44-24961852, 91-44-24963142

Mail : [email protected],

Web : www.vimicrosystems.com

mailto:[email protected],

http://gopher//

http://gopher//

mailto:[email protected],

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SPEED CONTROL MODULE TRAINER VPAT-10

Vi Microsystems Pvt. Ltd., [ 1 ]

INTRODUCTION

The Speed of the AC motor is controlled using Versamax Micro PLC. The PLC acts as a error

detector and controller (PID).

The set point is given to PLC and the PLC compares the setpoint (SP) and process variable (PV)

from the motor and creates an error value and produces the control variable (CV) to the motor

unit. Thus the motor is controlled using PLC.

SPEED CONTROL MODULE:

This module maintains the speed of AC motor to the set point using PLC. The speed of the

motor is measured using optocoupler sensor. The output of optocoupler will be a series of pulses

depending upon speed of the motor. This pulses are converted into voltage using frequency to

voltage converter.

This voltage is a process variable (PV) and is applied to the analog input of PLC. The set point

Is given through the software. The PID control action was taken by the PLC and gives the

controlled output analog output channel. This controlled output will maintain the speed of AC

motor at Its set point. Thus we form a closed loop control using PLC.

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FRONTPANEL DIAGRAM

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PROGRAM EXPLANATIONS:

PID IND BLOCK

The independent algorithm (PID IND) is the close loop control algorithm. The PID function has

six input parameter: a process set point (SP), a process variable (PV) , a manual / auto Booelan

switch (MAN), a manual mode up adjustment input (UP), and manual mode down adjustment

(DN). It also has an address, which specifies the location of a block of parameters associated

with the function. It has two output parameters, a successful Boolean output and the control

variable result (CV).

If the manual input is true, the PID block is placed in manual mode and the output control

variable is set from the Manual command paramter %Ref + 13. If either the UP or DN inputs

are true, the manual command word is incremented or decremented by one CV count every PID

solution. For faster manual changes of the output control variable, it is also possible to add or

subtract any CV count value directly fo / from the manual command word.

Parameter Description

Address The Variable's address is the location of the PID control block information, which

consists of 40 consecutive registers of %R, %P, or %L memory.

SP SP is the control loop set point.

Data Type: WORD

PV PV is the control loop process variable.

Data type : word.

MAN When energised, the PID function is in MANUAL mode.

UP When energised, if in MANUAL mode, the CV output is adjusted up.

DN When energised, if in MANUAL mode, the CV output is adjusted down.

SCALE INT

Use this function to scale an input value and place it in an accumulator. This function has five

inputs/parameters. For the integer based version of the function (SCALE-fNT) all the paramets

be integer based (signed).

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Parameter Description

IHI This input can either be %R, %AI, %AQ reference memory or constant. It

represents the maximum input value.

ILO This input can either be %R, %Al, %AQ reference memory or constant. It

represents minimum input value.

OHI This input can either be %R, %Al, %AQ reference memory or constant. It

represents maximum scale value. When the IN input is at the IN Hi value, the

accumulator value is the same as the OHI value.

OLO This input can either be %R, %Al, %AQ reference memory or constant. It

represents the minimum scaled value. When the IN input Is at ILO value, the

accumulator value is the same as of the OLO value.

IN This input can either be %R, %Al, %AQ reference memory or constant. It

represents the value to be scaled.

Analog Input to PLC Process Variable (PV) from the'motor.

Analog output from PLC Control variable (CV) to the motor.

The set point is given to PLC. The- process variable (PV) from the motor is given as input to the

Analog input of PLC. The PLC performs, the control operation and gives the control variable

(CV) to control AC motor.

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EXPERIMENT

AIM

To control the speed of the AC motor using Versamax Micro PLC.

APPARATUS REQUIRED

1. Speed Control Module Trainer (VPAT-10).

2. Versamax Micro PLC.

3. PC

4. RS-232Cable

5. AC Motor

6. Patch Chords.

THEORY

PID CONTROLLER

One of the most powerful but complex controller mode operations combines the proportional,

integral and derivative mode. This system can be used for virtually any process condition. The

analytical expression is .

PWhere K = Proportional gain between error and controller Ouptut (% per %)

pde / dt = Rate of change of error (%S)

DK = Derivative gain constant (% - S/%)

IK = Scaling between error and controller output.

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Response of Three Mode

This mode eliminates the offset of the proportional mode and still provides fast response. Thethree mode controller action exhibits proportional, Integral and derivative action.

RELAY LADDER DIAGRAM

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Where ICR = Coil

Ref = Reference

PID = Proportional + Integral + Derivative.

PROCEDURE

1. Load the Versapro Software in PC.

2. Open the Versapro Software.

3. PLC kit is switches ON.

4. Interface PC to PLC through RS-232 cable.

5. Open the New Folder and draw the ladder logic program.

6. Connect the PLC.

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7. Select the correct hardware configuration [PLC Sl.No]

8. Store the program to PLC.

9. Using patch chards, connect the PLC analog output to the input of the PWM (i.e Analog

output of the speed control module trainer kit.).

10. Using Patch chards connect the speed control module trainer kit analog input to PLC

analog input.

11. Run the program

12. Check the motor speed [1500 rpm].

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CONNECTION DETAILS

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