Hi,
I was told that I can use the one counter in the NI USB 6501 to measure period. So, I wrote this little VI, modeled after the VI I have that measures encoder period using the counters built into the NI cDAQ 9174 with the NI 9401 digital I/O module. I have my encoder wires GND and 5VDC on terminals 1 and 2, respectively. Also, I have encoder channel A and Channel B wires connected to terminals 9 (P2.7) and 24 (P0.7) respectively. With the MAX, I can count edges with this wiring. The purpose of this VI is to display an average value of 25 period measurements of the encoder. The encoder (120 cpt) is turning at about 2-5 rev/second, so, not that fast, maybe a total of 500 period per second; should be easy for this counter. I'm just spinning it with my finger, so, not that fast.
Please advise how to use the USB 6501. I can't find any wiring instructions, other than the pinout, but, the pinout doesn't tell you which channel is the counter gate on the USB 6501, so, I found a response on MAX at channel 24.
When I run this, the array is correctly initialized to 0.5, but, then I get this error, 200431. I found some things on the forum that suggest I cannot measure period, that I can only count edges. Should I throw this 6501 away?
Thanks,
Dave