Hello, To start - I am new to working with LABVIEW and it's VIs - this could be a very obvious problem! I will attach my VI below (uploading issues) The Task and Problem: I have an encoder wired up to the DIs of a USB-6218 BNC, along with an external trigger signal also wired into a DI. This external trigger is coming from an output signal from a camera, sent at the point of image capture, and sampling at just under 1kHz for about a minute per test. I am interested in the position of the encoder at each frame of the camera, and I am recording information this way to maintain parity with other measurements. The issue is that I seem to be sampling more data points of the encoder position than there are frames from the camera. The VI set up: I have both sets of quadrature signals from the same encoder (A,B,Z and invA,invB,invZ) inputting into counters, then DAQmx Reads within a while loop and using the trigger signal as a sample clock. I have (through fudging and trial and error) set it up to record both encoder position signals and the timestamp into an array per iteration of the loop and then, at the end of the test (Manual STOP) send this array to write to a .csv file. The VI functions as I would like bar the extra data. I can post-process the data to remove the extra entries but the project really needs two data sets of the same length. The USB-6218 does not have a minimum sample rate. How do I set this VI to record data from each and only each sample clock pulse? Thanks

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Hello Kevin,

Thanks for this clarification. I now have a number of things to check to get to the bottom of this!

I will reply to this thread once I have worked out the source of the problem.

Many thanks,

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