Route a Counter generating a Pulse Train to Any PFI Line on CompactDAQ

[gdlbb]

Hi everyone,

I'm trying to route a Counter output to a different PFI line than the default one on a CompactDAQ-9172 with NI 9474.

I found this example on NI Wedsite for M series: http://zone.ni.com/devzone/cda/epd/p/id/4422

I tried it without changing anything and let's say, It works a little bit 🙂

So for instance in the counter list, I chose ctr0 or 1 and in the output terminal, I chose PFI0. I launch the .vi And then LED 0 is blinking at 1hz, as it should be.

but then, I change to PFI1, and then LED 0 and 1 are blinking !

and if I choose PF7, LED 7 will blink with the other ones.

It looks like it remembers the last line I chose.

If I close labview and re open it, it's the same. (I chose PF0 and PFI0,1 and 7 are blinking all together)

the only way to reset it is by unpluging the usb cable between the compactDAQ and computer. (however, you don't need to turn off the cDAQ itself)

Do you have any idea where does this can come from ?

Encolsed the.vi I'm using.

Thanks a lot !

Guillaume.

[gdlbb]

I don't understand even more because on the VI attached it said they have used DAQmx Tristate output terminal especially for that :

"step 7 : Call the DAQmx Tristate Output Terminal to disconnect the path between the signal being generated and the selected PFI line. If this was not used, then once a task is created with a certain PFI line selected, that PFI line would still be driven by the pulse regardless of the PFI line selected in step 2. "

[R_Duval]

Hi Guillaume.

Could you use "DAQmx Connect Terminals.vi" to create an explicit route as specified by the inputs, and you could call "DAQmx Disconnect Terminals.vi" to clear the route.

Do you have the same issue in this case?

Best Regards,

[stilly32]

Hi Guillaume,

What you are seeing is expected behavior. PFI lines have a behavior called "Lazy Uncommit" in which routes made stay connected until they are reset or claimed by another task. You can clear a route by calling DAQmx Tristate, commiting an input on the line, or resetting the device with DAQmx Reset.

Cheers,

Andrew S 

[gdlbb]

I'm sorry I did not reply sooner, thanks  you very much for your replies.

Yes I tried with the .vi export signal in two different ways and I did not succeed.

Daq-mx reset did not work either..

But, I manage to do what I want with this .vi I modified.

I found the original here :  http://zone.ni.com/devzone/cda/epd/p/id/5043

the .vi used a quite complex sub-vi to get the internal counter ouput (check it out)

many thanks !

Guillaume.

EDIT : With connect and disconnect terminals, I did not suceed also, the Connect terminal vi don't connect anything with me 😞

Message Edited by gdlbb on 02-02-2010 06:29 AM