problem of getting very low temperature from RTD measurements with USB 6009

[RTD measurment with USB 6009]

Hello:

I'm using USB 6009 for measuring temperatures from RTD (model: Omega, RTD 805). I'm facing a problem while taking readings:

I'm getting wrong readings, such -242 deg C, which is very low as compared to room temperature. I don't know how to fix this problem. In the DAQ assistant express VI settings, I use Pt 3851, Ro=100, excitation= external, Iex value=2.5mA

Please let me know about my problem, how to fix it. I tried to search it in NI, but didn't get any help.

Hoping to get a response soon.

Thanks!

Regards, Mandeep

[Dennis_Knutson]

So what are you using for the external excitation since the 6009 cannot provide it?

[Zachmx]

You may want to take a look at the KnowledgeBase article about connecting an RTD to a DAQ card.

http://digital.ni.com/public.nsf/allkb/5BFB36CFCC32C662862570D5006DC0C0

Dennis is correct about the excitation source, are you using an external one?

[RTD measurment with USB 6009]

Hi,

Yes you are right, USB 6009 doesn't provide current excitation.

Can I use NI 9201 USB for measuring RTD? I have USB 6009 and USB 9201 DAQ devices in my lab, and I'm thinking to use both if it's feasible to measure RTD with these, since USB 9201 has 8 analog input channels. But, I'm not sure whether I can use USB 9201 DAQ for RTD measurements. It's written in the instruction sheet that 9201 model is useful for signaling RTD. Please let me know a cheap RTD measurement DAQ device if the above mentioned 9201 model is not a feasible option.

Thank you in advance.

Regards,

Mandeep 

[SnowMule]

Why try and adapt a 600x that's made for generic voltage measurements to an RTD measurement system, instead of just buying a module built for doing temp measurements?

http://sine.ni.com/np/app/main/p/bot/no/ap/daq/lang/en/pg/1/sn/n17:daq,n24:cDAQ,n36:10/