Hi Chris,
The USB 6241 isn't what we'd normally recommend in order to take 3 wire RTD readings: it's designed to be a high speed DAQ device and doesn't have the right terminals to do the job. Because an RTD is a passive resistive device, you must pass a current through the device and monitor the resulting voltage, but the USB 6241 doesn't have a current source or EX terminal which I believe would be needed.
We do however sell hardware that is more suitable. I would recommend calling our technical sales engineers who will be able to advise you on the best device to buy. People are put off by the word sales but they're really looking have a chat about what would best suit your needs rather than just sell you things! Your local team can be reached through the Contact Us link at the bottom of this page.
For more information on using RTDs with NI hardware, see the following articles:
Taking Temperature Measurements with RTDs: How-To Guide
https://knowledge.ni.com/KnowledgeArticleDetails?id=kA03q000000x1rnCAA&l=en-US
Measure Temperature using a RTD, myDAQ, and LabVIEW
https://forums.ni.com/t5/Example-Code/Measure-Temperature-using-a-RTD-myDAQ-and-LabVIEW/ta-p/3996486
Best regards,
Leah
