SLC 500 temperature control

[pauly]

What would the forum agree to be the best way of achieving temperature control via a slc 500 plc.The application is electrically heated via solid state rlays which implies the use of time proportioned outputs. I am debating the use of special temperature modules which cater for the required type of output and auto tuning.
The customer doesn't want discreet controllers.
Any opinions would be gratefully received

 

[JesperMP]

Sorry, misplaced reply !

(hmmm. how do you delete a reply ?)

 

[stephenkeeley]

I have done numerous applications with both the SLC 500 thermocouple input module and the SLC 500 BTM module which has autotune built in. The BTM module does not autotune as well as a stand-alone temp controller like a Cal 9000 or Barber Coleman. There is also a lot of overhead required with a BTM if you are controlling a lot of zones.

 

[oldgearhead]

Temperature

I've controlled several (200) very large gas burners using only:
the SLC's PID block. If you have a stand-alone controller, Honeywell
BC, etc that does control the process, and you can read it's PID
parameters, just transfer them to the SLC. Some parameters units may need to be converted, and, of course, test, test, test...Also, in
addition to the proper input device for the SLC, be sure and use
solid state outputs to drive your SSR's. (Contacts won't hold up)

 

[Tom Jenkins]

I doubt there is a "best" way. Any nuymber of techniques will work, if they are engineered and implemented properly. And, the set of acceptable techniques varies depending on the application. Simple "thermostat emulator" logic may work just fine for some applications, PID may be fine, the SMC algorithm discussed in detail on this forum will work beautifully, and so on.

There are no magic bullets, no universal best techniques.