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reading 2 channel pulse output from flow meter

I am new to labview and am using the usb-6341. i picked this based on my overall needs and discussions with NI support. I am trying to read freq and direction from my flow meter. ultimately, i will need to display freq in terms of gpm or lpm and my direction of flow through the flow meter as positive or negative flow. the flow meter has 2 square wave outputs 90 deg out of phase similar to an encoder output. each pulse represents a single gear tooth displacement from the meter. myend game is to display both flow and direction graphically in t-y and xy plots real time.i can display freq using only one channel but i am having difficulty displaying freq and direction in the stock options available to me in labview. any help would be greatly appreciated. i am including the wiring diagram for my flow meter.

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How do you plan to condition/change your signal? The encoder signals are not TTL-level, because then it would be very easy: Just treat your two signals as a quadrature encoder and connect it to the counter of your USB-daqcard. You get the direction by checking if the position counts rise or fall, frequency can be calculated within the software, just take the position change between 2 different timestamps, frequency = Delta of counts/delta T.


But don't forget, your encoder signals cannot be connected to our daqcard directly!!!


Regards, Jens

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