PROCESS CONTROL TRAINER-II
To see the change in system response due to noise and disturbance.
To obtain the frequency response of the system
Tune a compound controller for the system.
A process control trainer simulates the industrial plant, and control of temperature in the
plant. It hasa blower and heater, which acts as kiln, the blower is used to communicate the
information to the thermistor which is used to measure temperature. The measured
temperature can be fed back to the system input the error in the heater. Also the feedback can
be stepped or continuous. This emulates a industrial plant where temperature control is a
crucial part of operation management.
Observations and Results:
Disturbance and System Response:
1. If throttle control is increased, the measured value decreases but the controller
compensates for it.
2. If proportional band is decreased, the measured value decreases, i.e steady state
for reading refer last pages:
For closed loop:
Vout T(s) delay phase Freq(Hz) gain
9 4.5 180 0.111111 -2.38373
2.4 1.4 210 0.416667 -3.8764
1.92 1.2 225 0.520833 -4.73144
1.22 0.9 265 0.819672 -9.37042
0.98 0.78 286 1.020408 -11.0568
Proportional band for closed loop = 1.08/4*100=30 (app)
Note: Nyquist plots are attached at the end.
Compound controller Action:
When connected simply with the controller unit the output is oscillatory and as
After tweaking with controller we observe following
1. Increasing integrator control causes less oscillation but more transience.
2. Increasing derivative control causes more oscillation, but output settles fast.
3. Increasing proportional control, without applying derivative or integral control
causes decrease in steady state error.
4. However non oscillatory response is obtained by increasing proportional control.