Siemens SIMATIC S7-1200 Function Manual page 203

Note
Constant adaptation of the output value limits
Instead of the active updating of the controllers without access to the actuator described
here, this is implemented alternatively by constant adaptation of the output value limits in
other controller systems.
This is not possible with PID_Temp, because a change of the output value limits is not
supported in automatic mode.
Example: Control of a large boiler
PID_Temp is used for control of a large boiler.
The main goal is to control the temperature Input1. The controller PID_Temp_1 is used for
this purpose. In addition, the temperature Input2 is to be kept below a high limit at an
additional measuring point with the limiting controller PID_Temp_2.
Both temperatures are influenced by only one heater. The output value of the controller
corresponds to the heating power.
PID control
Function Manual, 03/2017, A5E35300227-AC
Using PID_Temp
6.6 Override control with PID_Temp
203