2-Wire & 4-Wire Analog Devices - Same Module

[brockaslan]

Hello!  What is my best option to get both 4-wire and 2-wire analog (4-20 mA) devices connected to the same C-series NI module?

I'm spec'ing out a cDAQ-9174 (4-slot) for my chassis.  Limited on space in the panel, so I can't go with an 8-slot chassis.  System power supply is 24 VDC.

Here are my I/O:

(1) digital (sinking) input.  Using the NI-9421 module for this input, which takes up (1) slot on the chassis.

(9) digital (sourcing) outputs. Using (2) NI-9474 modules for these outputs, which will take up (2) slots on the chassis.

(1) 2-wire analog current input.  Noshok 100 Series, 4-20 mA output pressure transducer.

(1) 4-wire analog current input.  Brooks Instruments 5860i mass flow meter.

As I type this, I believe I should be able to consolidate my digital inputs and outputs onto (1) NI-9375 module, leaving me (3) slots left.  Then I could get away with using (1) NI-9203 for the pressure transducer and (1) NI-9218 for the mass flow meter.  Even though that is probably a viable option, I still was wondering if there is an analog input module that accepts both 2-wire and 4-wire devices.  It looks like an NI-9218 might work (http://www.ni.com/product-documentation/54510/en/) with an NI-9983 adapter.

Really not familiar with 4-wire vs 2-wire current loops to know what will and won't work with any certainty.

[jesicadiaz]

Hi Brockaslan, 

What do you mean with " 2-wire and 4-wire devices"? Are those the bridge configurations? 
If that's the case, according to the specs of the NI-9218, fill bridge, half bridge and quarter bridge configurations are possible.
As far as the pressure transducer the output range of the Noshok 100 Series is between 4mA and 20 mA, the NI-9203 has an output range of ±20 mA. If you are going to be working with 20 mA, perhaps another NI module might suit your needs a little better. For this kind of technical questions I would suggest you call an Applications Engineer at National Instruments.  

Regards, 

[brockaslan]

Jesicadiaz,

Thanks for the reply.  Sorry for the poor nomenclature.  This question would probably make more sense on an electrical engineering forum.  But what I was trying to determine, was more how to wire the two different analog input sources (i.e. Noshok 100 Series pressure transducer vs. Brooks 5860i mass flow meter).  I've attached a picture of how I think they should be wired.  I know the Noshok is wired properly - have used it before with success on an NI-9203.  Haven't wired the mass flow meter, but it looks like the NI-9203 won't work.