Pid Adjustment - THORLABS ITC502 Operation Manual

2.15.4 PID adjustment

Temperature control loops are comparatively slow control loops with control
oscillations in the Hertz range.
The PID adjustment will optimize the dynamic behavior. With the ITC5xx the three
parameters P, I and D may be selected independently.
2.15.4.1 Example of a PID adjustment
(Preconditions: All limit values have been set correctly, all polarities are correct, a
suitable sensor is connected and selected.
1. Set the P- I- and D-share to 0 (7 o'clock)
2. Switch on the output (button TEC ON) and observe the actual temperature.
(In some cases it is useful to connect a storage oscilloscope to the TEMP OUT
output)
2.15.4.2 P-share
3. Change the set temperature repeatedly between values of ambient
temperature +2°C and ambient temperature -2°C and observe the settling
behavior of the actual temperature.
Increase the P-share gradually by turning the corresponding potentiometer
clockwise.
Higher values will increase the settling speed, at the same time the stability
reserve will be decreased so that number and amplitude of the overshoots will
increase.
The P-share has been set correctly when the actual temperature remains
stable near the set temperature after only 2-3 overshoots.
2.15 Setup and function of temperature controllers
ITC500 / page 45