Siemens SIMATIC S7-1200 Function Manual page 128

Using PID_3Step
5.2 PID_3Step V2
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 PID_3Step sampling time. All
other functions of PID_3Step are executed at every call.
Dead band width
The deadband suppresses the noise component in the steady controller state. The dead
band width specifies the size of the dead band. The dead band is off if the dead band width
is 0.0.
If values not equal to 1.0 are configured for the proportional action weighting or the derivative
action weighting, setpoint changes even within the dead zone affect the output value.
Process value changes within the dead zone do not affect the output value, regardless of the
weighting.
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Function Manual, 03/2017, A5E35300227-AC
PID control