Installation manual

900M050U00  Athena Controls, Inc. 16-1
16. Tuning the Controller for PID Control
16.1 Introduction
When Proportional-Integral-Derivative (PID) control is used, the controller modulates
output power by adjusting the output power percentage within a proportional band.
Power is proportionally reduced as the process temperature gets closer to the setpoint
temperature. The integral action affects the output based on the duration of the process
value’s variation from the setpoint, and the derivative action affects the output based on
the rate of change of the process value. If both standard outputs are used for PID
control, then the same integral and derivative parameters apply to both outputs.
Proportional band is specified for each output individually, unless both outputs use the
same action (direct or reverse).
The proportional band, derivative action (rate), and integral action (auto reset)
parameters are automatically adjusted by the Autotune operation described in 16.2.
Autotune is best suited to temperature control applications. Some other applications may
respond well to Autotune. However, some non-temperature control applications may
require manual tuning, in which the proportional band, derivative action (rate), and
integral term or manual reset are entered using the control menu as described in 16.3.