ni 9218 and temperature or resistance measurement

[binature]

I'm looking for advise on ways that the NI 9218 could be used to measure resistance from an RTD that will operate in the 100 to 140 Ohm range.  I understand that a channel of the 9218 can be configured to measure current (+/- 20 mA).   So I would think that it might be possible to setup a configuration to measure the resistance indirectly by converting the measured current to resistance using V=IR.  Is this reasonable and possible?

[jspeedz]

It may be possible, but you will have to verify a few things. RTD measurements require current excitation, and the NI 9218 has limited current excitation.  You will need to verify that this module can provde the necessary excitation for your RTD. Here is a document that explains this idea for strain gauge excitation:

http://digital.ni.com/public.nsf/allkb/44BFBF71726610B286257D85005945B9

What type of RTD are you using?

A much better option would be to use an NI 9217 module which is designed for RTD measurements.

[binature]

Thanks for your help and the link.  I'm thinking of using an Omega RTD possibly a SA1-RTD

http://www.omega.com/pptst/SA1-RTD.html

But I could work with a different RTD if need be.  The SA1-RTD gives 100 ohms at 32 degrees F which would be the lowest temperature (and resistance) that I would need to measure.  Maybe I could put a fixed resistor in series with the RTD and get the resistance level a bit higher and use less current.

I'm trying to avoid the addtion of another module to the system that Im working with and I do have a single channel available for a temperature measuement on the 9218.

[jspeedz]

It may be possible to configure that RTD to work.  I would consider starting a new thread for this issue so your post gets higher visibility.  Hopefully someone in the NI community has successfully used an NI 9218 for an RTD measurement.