Hello all,

I'm trying to run PID compact on a S7-1211C. The thing is, this worked before, and now there is no output. I'm new to PLC programming so I'm sure I've missed some basic setting, but I can't find anything different from the previous config. I've tried resetting through the reset input, the mode is mode 3 and I've changed the setpoint to various settings. It does work in manual mode, just not in PID. Any help is greatly appreciated.

Regards,

Daragh

 

Hello,
In your second picture, the "ModeActivate" input is off, this input is what starts the PID calculation. See the link below for more information. The manual doesn't mention if the activate input needs to be on the whole time or a one-shot.
PID_Compact manual

 

Hi Shawn,

Thanks for that, but unfortunately it still doesn't work. I've tried both whole time and one shot at the "ModeActivate" input.

Daragh

 

Does the "invert control logic" option need to be changed so the PID controller is reverse acting?