Siemens SIMATIC S7-1200 Function Manual page 172

Using PID_Temp
6.2 Configuring PID_Temp
The "Minimum ON time" and the "Minimum OFF time" can be set separately for heating and
cooling, rounded to an integer multiple of the PID_Temp sampling time.
A pulse or a break is never shorter than the minimum ON or OFF time. The inaccuracies this
causes are added up and compensated in the next cycle.
Example for OutputHeat_PWM
PID_Temp sampling time = 100 ms
PID algorithm sampling time = 1000 ms
Minimum ON time = 200 ms
The PID output value PidOutputSum amounts to 15% constantly. The smallest pulse that
PID_Temp can output corresponds to 20%. In the first cycle, no pulse is output. In the
second cycle, the pulse not output in the first cycle is added to the pulse of the second cycle.
①
②
⑤
In order to minimize operation frequency and conserve the actuator, extend the minimum ON
and OFF times.
If you have selected OutputHeat/OutputCool or OutputHeat_PER/OutputCool_PER as the
output in the basic settings, the minimum ON time and the minimum OFF time are not
evaluated and cannot be changed.
172
PID_Temp sampling time
PID algorithm sampling time for heating
Minimum ON time
Function Manual, 03/2017, A5E35300227-AC
PID control