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Using NI 9402 with PX309 analog Pressure Transducer



First time poster to the forum, but I've been reviewing a number of threads while trying to design my DAQ system.  I recently made a purchase from NI for the NI 9402, based on the recommendation from a NI program engineer.


I sent him the attached (sites not letting me attach, so here is the url: specs for 3 pressure transducers that I need to monitor my system. The specifications on the transducers are as follows:



- Excitation 9 - 30 Vdc

- Output 0 - 5Vdc

- Three wires: Excitation + (red), Excitation - (Black), and Ouptut + (white)


Does this selection make sense (to use NI 9402 with analog transducers)? Obviously, this is not my area of expertise, but after reviewing some threads it doesn't seem to make sense. Would I need an A/D converter and external power supply to make this work, if it is possible? Any help is appreciated, and please let me know if you need more information.


Ideally, I would like a DAQ module that can provide power and read the input to the transducers.



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Message 1 of 5

The 9402 is a 4 channel digital IO!

Unless you want to monitor digital pressure events (with some hysteresis) that doesn't seems to be the appropriate hardware.


I haven't found any power consumption spec in the datasheet. 9-30V OK but how many mA???  You have to ask Omega for this information.



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Message 2 of 5

I would talk with the NI engineer that sold you the 9402 and try to explain your needs again.  It might also make it easier to return the 9402 and get the proper hardware.  If you are using a CDAQ system then you would probably want something similar to the 9215.  You will also more than likely need the external power supply to power the transducers.  Most DAQ can usually supply +5 Vdc, but the transducers want 9-30 Vdc (<10mA).

Message 3 of 5

Thank you Henrik and Bryan for confirming what I was worried about.


The transducer requires 9 - 30 VDC, (<10mA) as Bryan said, and confirmed with Omega Eng.


I was looking at potentially using the NI 9219 (as described in this thread, Would you recommend the NI 9215 over this product?


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Message 4 of 5

You could use the 9219 if you need/want a multifunction card for other testing down the road.  But I do not think it would help for your current testing.  The thread you linked to explains how you could use the excitation from the card by using a spare channel.  But if you read the specs for the card (9219) it only puts out 2.5 volts.


I would still recommend getting in touch with NI about all the options.  I only picked the 9215 as an example based on 3 channels of 0-5 Vdc input.  There are a handful of other specs that might be relevant to your project that I do not know.  I don't know what sample rate or accuracy you are looking for.  I also tend to get a card with more channels than I need because someone usually adds a few more channels once the test starts. 

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