AB MicroLogix 1200 PLC Close Loop Control


Thread Starter

Minesh Desai

I have an Allen Bradley PLC MicroLogix 1200. I want to know simple PID loop program for temp. control as well as pressure control (input 4-20 mA). If my PT range is 0-10 ksc, how to do scaling for PV & SP? Method to do PID tuning to get best control? Also how to take print out for trend?

bob peterson

I would suggest reading the blurb in the RSLogix 500 help file on the PID instructions and the SLC500 instruction set reference under PID instruction. It has its own chapter and is actually very good.

IIRC, the PID loop instruction expects the PV to be scaled 0-16383=0-100% but my memory might be faulty. Its in the help and instruction set reference.

As for tuning, it is no different than any other PID loop.

As for trending, the RSlogix 500 software has trending built in. There
should be a help topic for that as well.