I have to control 20 heaters in a Siemens S7-300 PLC. I use a thermocouple for each heater and a pulse modulated output to control the heaters.
This is working fine, except the PID parameters themselves.

I can set the PID parameters manually by looking at a step response and doing a lot of calculations, but I think it can go much easier letting the PLC find out what parameters are needed

Has anyone a PLC function or just the theorie to autotune those PID parameters so I can build a PLC function myself.

 

Hello!
I found this page in looking some help with modems...anyway, in the last year I have some experience with PID control with S7-300. I mean it could be interesting sharing this experience...

if you want more examples of my work, just ask and mail...
my project included control with pulse controled valves.

So, this is sometimes my work--you can get my functions!

 

hi
what I found is in the 355 handbook under the area 'parameteroptimirung'. I personally haven't used this function, i calculated it, the exact same setup.
you can download the HB from the website.
have fun
zan

 

There have been a number of autotuning routines developed within Siemens. The one that may best fit your application was developed by the plastics groups some time ago. I've implemented the software and it works quite well. Siemens
also sells other autotuning software add-on's for Step 7.

Send me your email address and I will send you additional information.

Regards,

Dave Cole
Sr. Sales Engineer
Siemens Energy and Automation
Fort Wayne, IN, USA
[email protected]