Reading output voltage from pressure transducer

[fowlerd8]

Hello all,

I am writing for help regarding the setup I am trying to achieve.  I am trying to read an output voltage from my MPX2010DP pressure transducer.  It is rated for 0-1.45 PSI, and a full range of 25mV.  I am using it to read pressure from a pitot tube I have set up in a duct system.  

The model I am using has 4 pin connections: 1 = Ground, 2 = V+out, 3 = Vsupply, and             4 = V-out.  I hooked up my power supply ground to pin 1 and the live to pin 3.  I then hooked up the outputs pin 2 and pin 4 to the NI 9215 AI3+ and AI3-.  The result was disappointing.  I then realized I need signal conditioning to read the mV range, which the NI 9215 AI has available.  I hooked it up, and get random numbers, both negative and positive nearly 0.

I have an exterior power supply, an NI 9219 AI, 9215 AI, NI 9472 DO, and a NI 9263 AO.  All are housed in the NI cDAQ-9172.  

1) What did I do wrong with my original setup?  Obviously the 9215 doesn't have signal conditioning, but when using the 9219 that does have the signal conditioning, I received data about once every 5-8 seconds.  

2) I have heard the NI 9237 is recommended for this, but I don't believe we have one here onsite.  Is that strongly recommended to use?  Would it fit this specific application?

3) What would be a VI to test my setup? I just used DAQ assistant and a while loop, but I got random small numbers for my data.

Thanks!

http://www.farnell.com/datasheets/2291387.pdf?_ga=2.230655071.2124413838.1534440267-810072295.153444...

[Ben]

Is the ground from your power supply/sensor tied to the ground of the AI device? 

If they are not referenced to the same ground you may be exceeding the CMR of the DAQ device.

You will also have to use the lowest range for the AI task.

The 5-8 seconds could be because you are using high-resolution mode that slows down how quickly you can take samples. Also consider that sample rates are often aggregate so if the sample rate is once a second across 8 channels ... a sample once every 8 seconds.

Ben