Siemens TIA P (v13) PID compact troubles

[DairyBoy]

I have set up some "PID_Temp" loops in a 1517F3 processor and they seem to work ok. For pressure and flow rate I've used "PID_Compact". The issue is that one of them only outputs it's manual value, even when the manual enable i/p is false. I've checked the output address and man en i/p for multiple use. All clear. Is this just another bug? Thanks.

 

[JRW]

Sounds like a programming error...
Are the PID's called from a cycle OB?...
Cycle time correct?....
Overwriting any instance data block bits etc?.....
Separate instance data blocks?...

 

[martin_co]

Hi,

you should check the value of the tags "RunModeByStartup" and "Mode".
If "RunModeByStartup" = TRUE, then the PID will go to the operating mode specified by tag "Mode" after a CPU STOP -> RUN transition.
The default value of "Mode" is 4, so PID will start with manual mode after download, if "Mode" was not changed before.
If you want him to start in automatic mode you could change to "Mode" = 3.

During operation the value of "State" will always be written back to "Mode". So the PID will restart with the last operating mode if there are further STOP -> RUN transition of the CPU.

Regards