1. Stabilize the process
either manually or automatically.
2. Set the controller to
manual mode (if the controller is still running under auto mode).
3. Record the initial value
of the controller's output.
4. Mark a starting position.
A starting position must be several second a head.
5. When the recorder's pen
reaches the starting point, make a bump at the controller's output of about
5 to 20%.
6. Record the final value
of the controller's output.
7. Stop the test when
ample of response curve is recorded.
8. Return the process back
to operating condition.
Further reading on open-loop
process identification is available at:
1. Thomas B. Kinney, Tuning
Process Controllers, Chemical Engineering, 19 Sept. 83, pp 19-20
2. Bob Connel, Process Instrumentation
Applications Manual, McGraw-Hill Book Co., 1996, pp 212-213