I used Siemens CPU-414 to do PID control.
I created a OB35 to call FB41 and assigned
parameters for this function block, but when I
download it to PLC, turn PLC to run, I inputed a
value in PV_PER,and put a set value in SP_INT, but I couldn't get output value in LMN_PER . I have set all parameters as Siemens manual default
value.
I don't know my way is correct or not, and how to
test the PID is working.

Thanks and regards

 

The Loop by default is in Manual Mode. The Input "MAN_ON" is on, it must be "off" or 0 to go to Automatic Mode.

 

Hi All

A common error with this PID block is you need to generate a rising edge at the reset input to initialize the PID, I think the parameter is called COM_RST.

Donald Pittendrigh

 

> The Loop by default is in Manual Mode. The Input "MAN_ON" is on, it must be "off" or 0 to go to Automatic Mode.<

Thanks for your help.
I set some parameter as below, but it still can't
work,
set PVPER_ON to true, P_SEL and I_SEL MAN_ON to true,set PV_FAC and LMN_FAC to 1, other arameters all use default value.
But I couldn't get output from LMN_PER, no matter how to change SP_INT to make it is different
from PV_PER.