Pulse Train Generation on NI PCI-MIO-16E4 Not Continuous

[David Arthur]

Hello,

I have a BEI encoder signal that I am sending to the DAQ board counter
source pin (GPCTR0_SOURCE) which gives a frequency of 3600 pulses per
revolution.

I wish to trigger an analog input every 360 pulses per revolution so I
am trying to use the "Generate Pulse Train (DAQ-STC).vi" with an edge
and pulse delay of 5, effectively dividing the original signal by 10.
When I do this and read the signal coming from the counter output pin
(CPCTR0_OUT), I see a signal that is approximately 1/10 the original
(which is good), but the signal ceases after 1 or 2 seconds (which is
bad).

I can stop and re-start the .VI which gives me a signal for another 1
or 2 seconds. Is there some sort of buffer than may be filling
up?
Why does the signal disappear on the scope after a short time? I
require a continuous signal.

Any help would be greatly appreciated.

Cheers,
David A

[Brooks B.]

Hello David:

It sounds like you are doing everything right. Lets run a test... On the Generate Pulse Train (DAQ-STC).vi example, go to the front panel and change the "source specification" to "internal timebase" and specify a frequency and duty cycle (say 1000 Hz and 50%). Look at this on a scope. Does it stay on continuously or does it stop? If it stops also then you are most likely getting an error or the stop button is getting pressed. Does the VI stop also or just the pulse train generation? If this still stops, then try the Test Panels in MAX and see if that works. If both MAX and LabVIEW now works then the problem is with the source signal for the counter. That should get you going in the right direction for debugging...

Good Luck!

Sincere
ly,

Brooks B
Applications Engineer