Siemens SIMATIC S7-1200 Function Manual page 106

Using PID_Compact
4.3 PID_Compact V1
Derivative delay coefficient
The derivative delay coefficient delays the effect of the derivative action.
Derivative delay = derivative action time × derivative delay coefficient
● 0.0: Derivative action is effective for one cycle only and therefore almost not effective.
● 0.5: This value has proved useful in practice for controlled systems with one dominant
time constant.
● > 1.0: The greater the coefficient, the longer the effect of the derivative action is delayed.
Proportional action weighting
The proportional action may weaken with changes to the setpoint.
Values from 0.0 to 1.0 are applicable.
● 1.0: Proportional action for setpoint change is fully effective
● 0.0: Proportional action for setpoint change is not effective
The proportional action is always fully effective when the process value is changed.
Derivative action weighting
The derivative action may weaken with changes to the setpoint.
Values from 0.0 to 1.0 are applicable.
● 1.0: Derivative action is fully effective upon setpoint change
● 0.0: Derivative action is not effective upon setpoint change
The derivative action is always fully effective when the process value is changed.
PID algorithm sampling time
The controlled system needs a certain amount of time to respond to changes in the output
value. It is therefore not advisable to calculate the output value in every cycle. The sampling
time of the PID algorithm represents the time between two calculations of the output value. It
is calculated during tuning and rounded to a multiple of the cycle time. All other functions of
PID_Compact are executed at every call.
If you use Output_PWM, the accuracy of the output signal is determined by the ratio of the
PID algorithm sampling time to the cycle time of the OB. The PID algorithm sampling time
corresponds to the time period of the pulse width modulation. The cycle time should be at
least 10 times the PID algorithm sampling time.
106
Function Manual, 03/2017, A5E35300227-AC
PID control