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FiniteAcqExternalClock with differential inputs

I'm trying to use the function FiniteAcqExternalClock.m (provided as part of the "NI-DAQmx Tools for Data Acquisition" bundle; see


My hardware is PCI-6034E.


The function documentation makes reference to physical channels. In my case I want to use differential inputs, which are two physical channels each. For instance, differential input 0 is physical channels 0 and 8.


How do I acquire differential data with this function?


The larger problem I am trying to solve is simple: acquire externally clocked differential analog data. There must be a way to do this!


Any advice would be appreciated. Thanks! 



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Thank you for your question.  To acquire differential data, you just need to make sure that your input configuration is differential.  DAQmx takes care of the rest for you.  You are correct when you say that acquiring a differential analog input measurement involves connecting your signal to AI 0 and AI 8.  Just choose a differential input configuration for AI 0 and connect your signal to AI 0 and 8. 


To check this out for yourself, create an analog input task on channel 0 in Measurement and Automation Explorer.  After you create the task, click on the connection diagram.


To do externally clocking, just connect your externally signal to a PFI line and specify the PFI line as the source of your sample clock.  I hope this helps.




Todd V

National Instruments
Applications Engineer
NI Prototyping Community
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