Siemens SIMATIC S7-1200

Instructions
9.1 PID_Compact
PID control
Function Manual, 03/2017, A5E35300227-AC
293
9.1.5.5
Parameters State and sRet.i_Mode V1
Correlation of the parameters
The State parameter indicates the current operating mode of the PID controller. You cannot
modify the State parameter.
You need to modify the sRet.i_Mode tag to change the operating mode. This also applies
when the value for the new operating mode is already in sRet.i_Mode. First set sRet.i_Mode
= 0 and then sRet.i_Mode = 3. Provided the current operating mode of the controller
supports this change, State is set to the value of sRet.i_Mode.
When PID_Compact automatically switches the operating mode, the following applies: State
!= sRet.i_Mode.
Examples:
● Successful pretuning
State = 3 and sRet.i_Mode = 1
● Error
State = 0 and sRet.i_Mode remains at the same value, e.g sRet.i_Mode = 3
● ManualEnalbe = TRUE
State = 4 and sRet.i_Mode remain at the previous value, for example, sRet.i_Mode = 3
Note
You wish to repeat successful fine tuning without exiting
automatic mode with i_Mode =
0.
Setting sRet.i_Mode to an invalid value such as 9999 for one cycle has no effect on
State. Set Mode
= 2 in the next cycle. You can generate a change to sRet.i_Mode without
first switching to "inactive" mode.