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digital mixed with analog signals

I tried several ways to capture analog and digital signals. I would need more than the standard two allowed on the NI-9174, so I came up with this using digital lines on the NI-9401 cDAQ. What do you think about this method?

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The NI-9174 is a cDAQ chassis and does not directly measure analog or digital signals so you will need to use the C-series moduels (such as the NI-9401 as you stated). Maybe you could clarify what your are trying to acomplish. 


<Brian Aswege | Applications Engineering | National Instruments> 

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Their are only 2 counters provided on the NI-9174 and have using the 9401 you would have to use slot 5 or 6. I was asking if the attached would be a good way to read digital signals (frequency) using the NI-9174 and the 9401 and have 8 channels instead of being limited to 2. You also wouldn't have to worry about which slot the 9401 was in.

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Hello Bassinbc,


After looking over your post and your code, it looks like you want to take a frequency measurement with a NI 9401 in a cDAQ-9174. Currently you are using a Digital Input task to perform this measurement. I was suggest though to use counters to implement this measurement. I have added an example to this post that will help you get started with this. I am assuming that you are working with low Frequency digital signals.


As for the hardware configuration, the 9401 doesn't have to be placed in any particular slot for the NI-9174 but if you have a NI-9172, then you would have to place this module in slot 5 or 6. Finally, you are look at the device pinout in MAX to find out where to connect your sensor to it.


I hope this information helps but if you have any more questions, feel free to post.

Jim St
National Instruments
RF Product Support Engineer
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