Siemens SIMATIC S7-1200 Function Manual page 187

Requirements for fine tuning cooling
● Heat.EnableTuning = FALSE
● Cool.EnableTuning = TRUE
● The cooling output is activated (Config.ActivateCooling = TRUE).
● The PID parameter switching is activated (Config.AdvancedCooling = TRUE).
● The cooling output has to be active at the operating point where tuning is to be carried
out.
PidOutputSum < 0.0 (see tuning offset)
Process depends on initial situation
Fine tuning can be started from the following operating modes: "Inactive", "automatic mode",
or "manual mode".
Fine tuning proceeds as follows when started from:
● Automatic mode with PIDSelfTune.TIR.RunIn = FALSE (default)
Start fine tuning from automatic mode if you wish to improve the existing PID parameters
through tuning.
PID_Temp controls the system using the existing PID parameters until the control loop
has stabilized and the requirements for fine tuning have been met. Only then will fine
tuning start.
● Inactive, manual mode or automatic mode with PIDSelfTune.TIR.RunIn = TRUE
An attempt is made to reach the setpoint with the minimum or maximum output value
(two-point control):
– With minimum or maximum output value heating at fine tuning heating.
– With minimum or maximum output value cooling for fine tuning cooling.
This can produce increased overshoot. Fine tuning starts when the setpoint is reached.
If the setpoint cannot be reached, PID_Temp does not automatically abort tuning.
PID control
Function Manual, 03/2017, A5E35300227-AC
Using PID_Temp
6.3 Commissioning PID_Temp
187