Siemens SIMATIC S7-1200 Function Manual page 386

Instructions
9.3 PID_Temp
Example:
Output scaling when using output OutputHeat (cooling deactivated;
Config.Output.Heat.PidLowerLimit may be unequal to 0.0):
Example:
Output scaling when using output OutputHeat_PWM and OutputCool_PER (cooling
activated; Config.Output.Heat.PidLowerLimit must be 0.0):
With the exception of the "Inactive" operating mode, the value at an output is always located
between its scaled high output value and scaled low output value, for example, for
OutputHeat always between Config.Output.Heat.UpperScaling and
Config.Output.Heat.LowerScaling.
If you want to limit the value at the associated output, you therefore have to adapt these
scaling values as well.
Cascading
PID_Temp supports you when you use cascade control (see: Program creation (Page 193)).
Substitute output value
In the event of an error, PID_Temp can output a substitute output value that you define at the
SubstituteOutput tag. The substitute output value must be within the limits for the PID output
value. The values at the outputs for heating and cooling resulting from the substitute output
value are the result of the configured output scaling.
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Function Manual, 03/2017, A5E35300227-AC
PID control