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cRIO Expansion Chassis and cRIO 904x (with NI-DAQmx)

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Was pretty excited to see that the new cRIO 904x series now supports use of NI-DAQmx for data acquisition.  Will help get DAQ projects where I want to use a cRIO off the ground quickly.


My one question is with the current largest cRIO in the series having 8 slots, can we expand with an cRIO expansion chassis and access expanded IO with DAQmx as well?

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Message 1 of 9
Accepted by topic author mbremer
04-13-2018 04:33 PM

I do agree the new support for NI-DAQmx on the 904x line is a really great feature!


Unfortunately, the cRIO expansion chassis isn't able to be programmed with DAQmx. This is due to limitations of how they are set up from a hardware and software perspective. 

Casey G.
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Message 2 of 9
Accepted by topic author mbremer
04-13-2018 04:33 PM

A quick addendum to that:


While it isn't possible to access IO on a cRIO expansion chassis via DAQmx, this is absolutely possible with an ethernet cDAQ chassis (cDAQ-9185/9189). If you're looking to expand your IO beyond 8 slots, these cDAQ chassis would be a great fit!

Message 3 of 9

Oh cool, I didn't know that about the cDAQs. I'll definitely take a look!

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Message 4 of 9

Thanks for the clarification Willbur.


I have a similar question but with a few twists. Maybe you or someone here can help me figure this out:


Background: I am setting up a system in which I want to use cRIO controller (8 slot) for deterministic control (RT/FPGA) and expand on such capability with MXI-Express CompactRIO Chassis 9155 (+8 slots), while I want also to use a cDAQ chassis (+8 slots) for data collection. All the units will be sharing an encoder signal collected with a NI-9411 module on the main cRIO.


I found an article from NI "Control a cDAQ from a cRIO or cDAQ Controller" which indicates a cRIO 904x-905x is necessary to accomplish this cRIO-cDAQ configuration.


In this regard, I read "Expansion I/O for LabVIEW RIO Systems: An In-Depth Comparison" and I see that cRIO 904x does not seem to have MXI connection capability.


I wonder if I can expand a cRIO 904x with a cRIO MXI express expansion chassis while also expanding with a cDAQ chassis?



Thanks in advance

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Message 5 of 9

While a MXI expansion chassis isn't an option with the cRIO-904x, you could try using a cRIO ethernet expansion chassis (NI-9149). You can deploy a FPGA VI, acquire data from modules, and transfer data to the host cRIO with an ethernet expansion chassis the same way you'd do so with a MXI expansion chassis.

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Message 6 of 9

You may be right. I am just wondering if a cDAQ and a cRIO Ethernet chassis can be daisy chained? I assume most probably it will need a switch to connect in a start type of topology.


NI recommends EtherCat for expanding deterministic control but I am not sure if a cDAQ chassis can be included in this configuration. 


Wish NI had a chassis/controller/protocol updated compatibility matrix!


And just found the answer:


Thanks Wilbur

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Message 7 of 9



I also use this programing  mode.   But Now I want to save the data to SD card, do you know how to use it.



thanks in advance.

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Message 8 of 9

Hi kisyou,


Thanks for reaching out. It might be best to post your question on a new thread to get more visibility, since this post is pretty old.


Secondly, could you explain your question more? What do you not know how to use, the SD card or the DAQmx API?

Keddy C.
Technical Support Engineer
National Instruments
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