1756 I/O with IFM modules (thermcouple/RTD)

I am adding a new 1756-IRT8I to a system and I have been using IFM modules with this system. Unfortunately, I am seeing two different part numbers depending on whether the module is using RTDs or thermocouples. In our case, we'll be using both. Am I correct in assuming that I cannot use an IFM in this case?

1492-AIFM8S-3 for RTD
1492-AIFM8TC-3 for thermocouple

I'm not quite sure what you're asking. IFM is a manufacturer of instruments. They make RTDs and temperature transmitters but not thermocouples, as far as I know. What is the "IFM Module" you are referring to?


I don't think the card will take a 4-20mA signal, if that's what you're asking about.

rupij, FYI

IFM modules are a cabling and terminal system.
From Rockwell

phuz,

Why do you think you can't?

https://literature.rockwellautomation.com/idc/groups/literature/documents/br/1492-br016_-en-p.pdf

Mickey said:

rupij, FYI

phuz,

Why do you think you can't?

https://literature.rockwellautomation.com/idc/groups/literature/documents/br/1492-br016_-en-p.pdf

Click to expand...

Because they list a separate IFM module whether you are using RTDs or thermocouples. The customer is planning on both RTDs and Thermocouples connecting to the 1756-IRT8I but it looks like the IFM board will support only one connection type.

phuz said:

Because they list a separate IFM module whether you are using RTDs or thermocouples. The customer is planning on both RTDs and Thermocouples connecting to the 1756-IRT8I but it looks like the IFM board will support only one connection type.

Click to expand...

Oh??

I think a call to your local AB repr would be in order. Maybe someone here
has some experience with those. I don't.

As far as I know, they are different modules completely; they can only do one or the other, RTD or TC.

I, too, thought IFM was a sensor manufacturer. For those as mystified as I was, the topic under discussion is remote terminal blocks.



There are different model numbers for different sensor types because of the lead wiring requirements for each.

RTD's use copper wire for lead wire.

Thermocouples require thermocouple extension wire that is specific to the type of thermocouple used in the process to get a true thermocouple signal back to the terminals where the cold junction measurement is made.

So the remote terminals could use specific thermocouple extension wire, or if the remote terminal block is not specific for the type thermocouple is use, then it is likely that the cabling from the remote terminal block is copper wire and the cold junction (CJ) compensation is done at the remote terminal block. The CJC would require an extra pair of wires to communicate the CJ value to the input card/processor.