Calculate RPM using NI 9402

I am attempting my first simple Labview DAQ project, though I am more comfortable with Signal Express.
My torque sensor has a +/- 5Vdc, 60 pulse/revolution speed output. The speed will be up to 200 RPM, so I was aimed towards a NI 9402 High Speed Digital I/O module for my CompactDAQ chassis. When I used DAQ Assistent to configure the counter, it indicated that there were no supported devices found. Is there some easy code to calculate shaft RPM with the 9402 configured as a digital input?
Thanks
Solved!
Go to Solution.

I have the same module and am also trying to calculate RPM from a transducer that outputs 60 pulses/revolution however I am using the cRIO platfrom and I believe the Express scripts do not work with cRIO, correct? What would be the best way to go about programming this calculation then?
Best,
Dan

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Finally getting around to this again. My previous post is incorrect, as the code I am using is based on the single period measure (it's right there in the code). I am having a problem with the values returned with this method. Occasionally, the card will return a lower than expected count, resulting in a very large (and incorrect) RPM value. I'm thinking this must have something to do with arming the counter at some unfortunate and coincidental point on the gate signal, resulting in a short count. It must be an unlikely event, because I get thousands of good, consistent values for every one bad one.
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