Siemens SIMATIC S7-1200 Function Manual page 74

Using PID_Compact
4.2 PID_Compact V2
Control mode V2
Physical quantity
Select the physical quantity and unit of measurement for setpoint, process value, and
disturbance variable in the "Controller type" group. Setpoint, process value, and disturbance
variable is displayed in this unit of measurement.
Control logic
An increase of the output value is generally intended to cause an increase in the process
value. This is referred to as a normal control logic.
PID_Compact does not work with negative proportional gain. Select the check box "Invert
control logic" to reduce the process value with a higher output value.
Examples
● Opening the drain valve will reduce the level of a container's contents.
● Increasing cooling will reduce the temperature.
Startup characteristics
1. To switch to "Inactive" mode after CPU restart, clear the "Activate Mode after CPU
restart" check box.
To switch to the operating mode saved in the Mode parameter after CPU restart, select
the "Activate Mode after CPU restart" check box.
2. In the "Set Mode to" drop-down list, select the mode that is to be enabled after a
complete download to the device.
After a complete download to the device, PID_Compact starts in the selected operating
mode. With each additional restart, PID_Compact starts in the mode that was last saved
in Mode.
Example
You have selected the "Activate Mode after CPU restart" check box and the entry
"Pretuning" in the "Set Mode to" list. After a complete download to the device, PID_Compact
starts in the "Pretuning" mode. If pretuning is still active, PID_Compact starts in "Pretuning"
mode again after restart of the CPU. If pretuning was successfully completed and automatic
mode is active, PID_Compact starts in "Automatic mode" after restart of the CPU.
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Function Manual, 03/2017, A5E35300227-AC
PID control