Control Lab_Experiment 4

7/31/2019 Control Lab_Experiment 4

1/13

EEP 301 : CONTROL ENGG. LABORATORY

Experiment- 4

Process Control Trainer

GROUP MEMBERS:

VISHAL GAUTAM (2010EE20531) GOBIND PRASAD (2010EE20516) KAMAL KISHORE (2010EE20519) SURENDRA GEHLOT (2010EE20531) JAINESH KUMAR (2010EE20518) GHANSHYAM MEENA (2010EE20515) DEVENDRA KUMAR (2010EE20512)


2/13

Aim: To perform experiment on 37-100 Process Control Trainerand demonstrate the characteristics such as Distance/Velocity

lag, Transfer Lag, System Response and PID control etc.

Introduction: In this equipment, air drawn from the

atmosphere by a centrifugal blower is driven past a heater grid

and through a length of tubing to atmosphere again. The process

of heating the air flowing in the tube to the desired temperature

level and the purpose of the control equipment is to measure the

air temperature, compare it with the value set by the operator

and generate a control signal which determine the amount ofelectrical power supplied to the correcting element, in this case a

heater mounted adjacent to the blower.

Procedure:

The following assignments are carried out using the 37-100

process trainer.

System Response:

In this Part we have observed the system response in the terms of

Disturbance of the process , causing a change in the controlled

condition, may occur on the supply side or the demand side of the

system. In this process, supply side disturbances can be caused by

changes of inlet air flow, ambient air temp. or supply volt. to the

heater . The response of the system to a disturbance is dependent

on proportional band width.


3/13

Fig 1: Response to Step Change Disturbance

1. Adjust the set value to 50oc.

2. Set proportional band to 100%.

3. Adjust the blower throttle control to 4.

4. Place the 'detector probe' in the 11'' position.

5. Set the switch on the side of 37-100 to 'heater'.

6. Set the CRO according to specified value.


4/13

Observation:

(A) Proportional control = 100%

(i) Throttle control = 4

(ii) Throttle control = 5


5/13

(iii) Throttle control = 6

(B) Proportional control = 200%




6/13


(B) Proportional control = 30%




7/13


Closed Loop Open Loop

S.No. Throttle

Control

Measured

Value

Measured

Value

1 . 2 49 68

2. 3 48 62

3. 4 47 574. 5 46 54

5. 6 44 47

6. 7 43 45

7. 8 41 43


8/13

Distance/velocity Lag :

An alteration to the condition of a process affects the detecting

element after a time interval which is dependent on the velocity of

the process and the distance between the point of change and the

detector. This time interval L is the distance/velocity or transport lag,

as given by the equation:

L = distance/velocity

It is a pure lag, there being no change in the magnitude or form of

the signal. The effect of distance/velocity lag on different input

signals.

Set value is adjusted to 350C . Adjust the 'blower throttle control ' to 4 .


9/13

Process control trainer is kept in closed loop

S.No. Frequency Input

Amplitude

Output

Amplitude

1. 0.1 2.16v 1.44v

2. 0.5 2.08v 1.28v3. 1.5 3.4v 640mv

4. 2 4.16 400mv

5. 3 4.16 400mv

1.) For Frequency 0.1 Hz


10/13

2.) For Frequency 0.5 Hz

3. )For Frequency 1.5 Hz

4). For Frequency 2 Hz.


11/13

5. ) For Frequency 3 Hz

System becomes oscillatory for proportional band of 30 %

System becomes stable for proportional band of 60%


12/13

PID Control

Deviation, is the difference between the measured value of

controlled condition and the set value. Sustained deviation is termed

offset. In a controller with proportional controller, the output signal

is directly proportional to deviation, causing the correcting element

to supply more or less power to the process.

The relationship between deviation and controller output is defined

as proportional band. As proportional band is decreased, deviation

is decreased until a point is reached at which the system becomes

unstable.

Procedure:

1) Set the value to 400C.

2.) Observe the measured value of temperature.

Circuit Diagram for PID Control.


13/13

Observation:

S.No. Set Value Measured

Value

Kp KI

1. 40 34 0.1 -

2. 40 36 0.2 -

3. 40 40 - 1.06

For Kp = 0.6 , Ki = 0.1(with derivative circuit disabled )

For Kp = 0.3 , Ki = 0.1 , Kd = 10

Documents

Control Lab_Experiment 4