Siemens SIMATIC S7-1200 Function Manual page 183

Requirements for pretuning heating
● The difference between setpoint and process value is greater than 30% of the difference
between process value high limit and process value low limit.
● The distance between the setpoint and the process value is greater than 50% of the
setpoint.
● The setpoint is greater than the process value.
Requirements for pretuning heating and cooling
● The cooling output in the "Basic settings" is activated (Config.ActivateCooling = TRUE).
● The PID parameter switching in the "Basic settings of output value" is activated
(Config.AdvancedCooling = TRUE).
● The difference between setpoint and process value is greater than 30% of the difference
between process value high limit and process value low limit.
● The distance between the setpoint and the process value is greater than 50% of the
setpoint.
● The setpoint is greater than the process value.
Requirements for pretuning cooling
● The cooling output in the "Basic settings" is activated (Config.ActivateCooling = TRUE).
● The PID parameter switching in the "Basic settings of output value" is activated
(Config.AdvancedCooling = TRUE).
● "Pretuning heating" or "Pretuning heating and cooling" has been carried out successfully
(PIDSelfTune.SUT.ProcParHeatOk = TRUE). The same setpoint should be used for all
tunings.
● The difference between setpoint and process value is smaller than 5% of the difference
between process value high limit and process value low limit.
PID control
Function Manual, 03/2017, A5E35300227-AC
Using PID_Temp
6.3 Commissioning PID_Temp
183