Slip Rings for Thermocouples - Is using a RTD ( 10 vdc )better than using a Type J TC

Good Afternoon ,

It seems like we always have problems with using Type J Thermocouples with our slip rings .

Would using a RTD at 10 volts , be better than using a Type J that would be generating. millivolts ?

Thanks so much in advance .

If you decide to use a RTD, be sure to use a three-wire type, but I think using a Type J to 4-20 mA signal conditioner on the rotating side of the slip ring would be your bet bet.

+1 For Converting to 4-20 first. Also if you have a lot of IO, I've done ethernet through a slip ring with remote IO.

As Gomez says, Remote IO would be the best, even something like an IO-Link system.

Steve's 4-20 converter on the rotating side would be my #2 choice, but yes, a three wire RTD would still perform better than a TC if going through slip rings.



A big problem with TC's isn't even the signal level, it is that every time you have a new transition connection, with different materials, you are creating additional thermocouple junctions, at different temperatures, and different contributions to the signal.

I've had great luck with wireless battery powered. If i sample in minutes its a few years for battery changes. Faster sampling faster battery depletion.

We did a few non contact IR with 0.25% accuracy if my memory isn't failing.

What's the problem with the Type J's?


durability?
loss of contact with the slipring causes open circuit?
jacket wear?
junction breaks?
noise pickup from grounded element?



Tough to consider a problem is the problem isn't stated . . .

Do you really think , a thermocouple on a slip ring is a well thought out application ?