Measurement Noise NI-9226 vs. NI-9219 for PT1000 sensor

[J.D.Keuning]

Hello,

I am looking for a DAQ solution for measuring 2 PT1000 sensors. My measurements will be done in a temperature stable (20 degrees C) environment and will take about 10s each. I would like to be able to measure temperature changes during these 10s in the order of (sub)mK with a sample rate around 2sps (both sensors). I want to interface the DAQ with matlab, so the cDAQ + USB range is where I looked.

I've found two devices that may give me what I need; NI-9226 (states a 1mK rms noise ~ 3mOhm) and the NI-9219 0.4ppm rms of range. Now my question is:

- How do I express the 9219 noise in mK for comparison? What is the 'range' when I use a PT1000. sensor? Is it simply 1000*0.4ppm = 0.4mOhm (therefore a better noise performance than the 9226?) or am I missing something? 

- Am I overlooking a device that can be used or is the 9219 my best option for noise performance?

I hope someone can clarify this for me. 

Thank you and best regards,

Jasper

[AJost · Accepted solution]

Hello Jasper,

So far your assumptions are (nearly) correct.

The actual range of the 9219 for PT1000 is 5.05kOhm (see page 8 of the specifications).

So the noise specification is 5.05kOhm*0.4ppm = 2mOhm ~0.7mK

So the 9219 is still the best in terms of noise, but only by a slight margin .

To my knowledge those two are the only devices which can be used.

Andreas

[J.D.Keuning]

Hi Andreas,

Thank you for your reply and pointing me to the actual range. I've gone and bought the 9219, so if I missed some other critical information, I'll find out soon!

Best regards,

Jasper