PID controller

(PID)

The controller calculates the output value from the difference between the Setpoint and the Actual Value.
The control parameters are Proportional Coefficient, Integral Time and Derivative Time.

Inputs

S	Setpoint	Target value of controller, e.g. target room temperature
A	Actual value	Current measured value
PC	Proportional Coefficient	Controller gain
IT	Integral Time	Integral time in [s]; typical range: 60...900 s
DT	Derivative Time	Derivative Time in [s]; typical range: 1...10 s
R	Reset	Triggers the integral value of the controller

Outputs

O

Output

Room temperature control example

The Setpoint and Actual Value are two temperatures. The output value is the control value of a valve actuator.

Functionality

Output A only sends if a value changes.
The controller calculates a new output value during the calculation cycle time of the logic engine (usually every 200 ms).

Limit output value parameter

Limits the output value to a range. If this range is exceeded, a limit is imposed on the integral value of the controller ("anti-wind-up").