How to do finite sample of angle position

[穆易]

I am using a PCI-6601 to do a finite sample of angle position. It must be sampled with an external clock according to Labview help. But I dont know the exact samples I should acquire, and dont know what time the external clock will stop. How can I get all the samples without a timeout error after the external clock stops ?

[Kevin_Price]

I *think* it's as simple as setting up your task for *continuous* sampling and regularly reading "all available samples" (leave # samples unwired or use special magic # -1).  The external clock seems to define the finite # of samples that will actually happen.

When the external clock stops, your DAQmx Read will immediately (and correctly) return 0 samples to you.  When this has happened for a long enough time, you'll recognize that there's no more clocking signal out there and you can end the loop.

-Kevin P