Siemens SIMATIC S7-1200 Function Manual page 296

Instructions
9.1 PID_Compact
State / Description of the operating mode
sRet.i_Mode
3 Automatic mode
In automatic mode, PID_Compact corrects the controlled system in accordance with the parameters speci-
fied.
The controller changes to automatic mode if one the following conditions is fulfilled:
Pretuning successfully completed
•
Fine tuning successfully completed
•
Change of variable sRet.i_Mode to the value 3.
•
After CPU startup or change from Stop to RUN mode, PID_Compact will start in the most recently active
operating mode. To retain PID_Compact in "Inactive" mode, set sb_RunModeByStartup = FALSE.
4 Manual mode
In manual mode, you specify a manual output value in the ManualValue parameter.
This operating mode is enabled if sRet.i_Mode = 4, or at the rising edge on ManualEnable. If ManualEnable
changes to TRUE, only State will change. sRet.i_Mode will retain its current value. PID_Compact will return
to the previous operating mode upon a falling edge at ManualEnable.
The change to automatic mode is bumpless.
See also
Output parameters of PID_Compact V1 (Page 287)
Pretuning V1 (Page 109)
Fine tuning V1 (Page 111)
"Manual" mode V1 (Page 113)
Tag i_Event_SUT V1 (Page 300)
Tag i_Event_TIR V1 (Page 301)
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Function Manual, 03/2017, A5E35300227-AC
PID control