Siemens SIMATIC S7-1200 Function Manual page 93

Example: Control of a gas pipeline
PID_Compact is used for control of a gas pipeline.
The main goal is to control the flow rate Input1. The controller PID_Compact_1 is used for
this purpose. In addition, the pressure Input2 (measured in flow direction in front of the valve)
is to be kept below the high limit with the limiting controller PID_Compact_2.
Flow rate and pressure are controlled by a single solenoid valve. The output value of the
controller corresponds to the valve opening: The valve is opened when the output value
increases. This means the flow rate increases (normal control logic) while the pressure drops
(inverted control logic).
The valve is controlled with the output value of PID_Compact in I/O format (parameter
Output_PER) by writing the program tag ActuatorInput.
The setpoint for the flow rate is specified at the parameter PID_Compact_1.Setpoint.
The pressure high limit is specified as setpoint at the parameter PID_Compact_2.Setpoint.
PID control
Function Manual, 03/2017, A5E35300227-AC
Using PID_Compact
4.2 PID_Compact V2
93