RTD input to PLC...

[cfordyce]

If a PLC does not have a special RTD input module, what is the best way to be able to read a RTD input with the PLC? Can an analog voltage or current input card be used with accuracy? Or are there economically feasable devices to convert the signal from the RTD? Any suggestions?

The RTDs are all 100ohm Platinum.

Mmmmmm.

 

[Macbeth]

Use an RTD to 4-20ms converter. For cost effective ones look at Kele. These are not any good for process control but are good for BAS uses. You cannot accurately use RTD to standard input modules for any steady current will cause the temp in the RTD to rise P=I*E. This is one of the draw back of RTD’s.

 

[joecontrol]

Also look at Inor I have calibrated these in the field and they seem to work quite well. Joecontrol

 

[electrageek]

ActionPak , Mighty Module, and RIS (Rochester Instrument System) also make convertors.