PID level Control not starting

Hello Jimbo;

There have been many, many discussions on the PID controllers (S/FB41, 42, 43) on this forum, and you can easily find them by using the Search box at the top right of this page. You will find many threads from members who have gone through the same questionning process.

Generally the source of these SFB/ FBs not starting is in the selection of 2 critical inputs: Com_RST ("complete restart") and Man_ON ("manual/auto mode").

Com_RST must be activated once, for one cycle of the PLC, to enable the FB4x calculations. Often the solution is to select a control bit (for example, M10.1) for that input, set it at the launch of the CPU (in OB100), then reset it as the last instruction of OB1.

Man_ON controls the manual and auto setting of the calculator. By default it is in manual mode, so no calculations are permitted. Select another control bit, and use it to place the S/FB 4x in auto mode for calculations to start.

if you have any more questions on your programming of the PID blocks, please add a screenshot showing what you have used so far, maybe we could add a few hints.

Hope this helps,

Daniel Chartier

Your question is not clear.While using PID control with setpoint and process value, process value will reach the set value if you have done all thing properly.This is done automatically by mathematics in PID function.

jimbo1234

 How can I achieve the same when in analogue mode by not having conflicting outputs.

First we should know your plan regarding the binary output (to run the motor) and the analog signal (to change the speed). First , we need to clear if you have done all requirement in software in a correct way.Please:

1. Be sure that you have downloaded the required instance DB regarding your PID and also your program to PLC.It is obvious but it was source of trouble HERE .
   
   
   
2. Make a VAT and fill it with the variables mentioned here (REGULATION.jpg ).Please upload a file like mine here for investigations.
   
   
   
3. If you have positive error signal with positive LMN and nothing happens on your hardware (speed change), you have done your hardware implementation in wrong way.
   
   
   
4. Share your program and what you have implemented electrically to trace your problem.