I have been using correlated DIO to synchronize digital input (DIN) with analog input (AI) on M-series devices (e.g. the NI6225). Correlated DIO is limited to Port0 (i.e. 8 lines). I now need to work with 16 or more DIN lines so the correlated DIO technique will not work using a single NI device. 1) Is it possible to install a second DIN device that supports correlated DIO. The idea would be to read DIN from Port0 on a NI6225 and Port0 on the second DIN device for a total of 16 DIN lines. Is this a possibility? 2) After reading another post I have been able to use change detection on Port0 to read from the DIN lines on Port1 and Port2 (i.e. Port0 drives the change detection). This is one half of the problem. The second half of the problem is how can I obtain an accurate read of the total number of AI samples so as to be able to synchronize the onset of DIN with a single time point in the AI? Is this possible to do? In other words, can the hardware ‘latch’ an accurate AI sample count at the time change detection occurred? Are there other techniques or methods that would let me synchronize DIN on 16 or more lines with AI? My application is written in C++ using VS2010 and runs in the Window environment (WinXP, Vista and Win7). Thanks, Ian

Multifunction DAQ

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Hello James,

Thanks for your help.

I am closing this thread and will ask my last question in a new thread.

Ian

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