PID control in a C Series PLC
Written by Toby Kilroy
Updated at March 24th, 2023
The PID and PIDAT function blocks in the C Series PLCs (CP, CJ, CS etc) is a very useful function block for universal closed loop control, such as pressure, flow or temperature loops. However some users have difficulty in getting this to work initially as the Function Block is very particular about the inputs. If any input values are out of range, the Function Block will not output a control value.
Also, CX-Programmer simulates almost all functions of a PLC, except for communications and PID control. So if testing your program in simulation and you do not see an output, this is probably the reason. By contrast, Sysmac Studio simulates PID.
Please refer to this code example for a fully documented setup of the PID Function Block to get you started.