Installation manual
Tuning the Controller for PID Control
900M050U00 ï Athena Controls, Inc. 16-5
6. While monitoring the recording device or plotting the displayed PV against time
manually, decrease the proportional band value by repeatedly halving the value until
a small, sustained temperature oscillation is observed. Measure the period in
seconds of one cycle of oscillation (âTâ on the diagram below).
T
7. Divide the period of oscillation (T) by 8. The resulting number (quotient) is the correct
derder (derivative) time in seconds.
8. Divide T by 2. The resulting number (quotient) is the correct integral time in seconds.
9. Multiply the proportional band value used in Step 6 (to obtain T) by 1.66 and enter
this as the new proportional band value.
Manual tuning of the heating output is complete. If the second output will be used for PID
cooling, set the cooling output type to PID. (It was disabled in Step 1 of the manual
tuning process.) Enter the proportional band value calculated in Step 9 for the cooling
output also. If overcooling results, increase the cooling proportional bandwidth. If too
little cooling action results, decrease the cooling proportional band.