Multifunction DAQ

cancel
Showing results for 
Search instead for 
Did you mean: 

Configuring a PFI Line in Traditional NIDAQ

Hi - I'm using traditional NIDAQ (v 7.0) with a PCI-6711 card; I'm trying
to connect an external clock signal to the analog output timebase signal
(i.e. to the UISOURCE signal, as it's called in the DAQ manual). I'm
having trouble with the following:
I'm using the PFI-7 line to bring in the external clock signal,
and in the manual (p. 4-13) it specifically says that the PFI line used
for this purpose should be configured in the level-detection mode.
What I would like to find out is how to do this configuration (specifically).
I looked at the documentation for the Select_Signal() command, but that
didn't look right, and I can't find anymore info on how to configure
PFI lines (in general) in the level-detxn mode (nor for the edge-detxn
mode, for that matter).

Any advice/comments are appreciated. Regards,

ARB
0 Kudos
Message 1 of 6
(2,323 Views)

Thank you for contacting National Instruments.  I believe that Select_Signal is the command that you are looking for.   You will want it to look something like this:

Select_Signal(devicenumber,ND_OUT_UPDATE_CLOCK_TIMEBASE,ND_PFI_0,ND_LOW_TO_HIGH OR ND_HIGH_TO_LOW)

where devicenumber is the actual device number and the ND_LOW_TO_HIGH OR ND_HIGH_TO_LOW parameter will be one or the other.  You can read more about this by looking at the Select_Signal in the Traditional NI-DAQ help.  The Signal Name Equivalenices Table tells you that the UISource is called by the name ND_OUT_UPDATE_CLOCK_TIMEBASE.  Then, you can read into the parameters for this by clicking on the link that says:

"Parameter Discussion for E Series, I Series, 671X, 673X, NI 5411, and DSA Devices"

Then, click on the ND_OUT_UPDATE_CLOCK_TIMEBASE link in the table.  This will give you the possible parameter values for the source and sourcespec parameters.

Hope this is helpful!
Jeff P.
National Instruments Applications Engineer

 

0 Kudos
Message 2 of 6
(2,311 Views)
hi Jeff,
Thanks for your reply; I'd already tried that what you suggested earlier, but that
doesn't work - if might be that I'm having an error somewhere else in the program,
and that my Select_Signal() call is actually the right thing to do.
One other question: in your reply you said that I should use ND_PFI_0 -- is there a reason for
that, or can I use ND_PFI_7 as I'm already doing (I remember the documentationa actually
saying that PFI_5 is the default ...)

Thanks again
0 Kudos
Message 3 of 6
(2,305 Views)

No, you're right, ND_PFI_7 is right.  I was copying code from the help file to save myself from Carpel Tunnel Smiley Happy!  That is the only call I could find that references the external clock.  The help files say that this is the call that you are using.  You might want to consider using the internal clock as default just to verify that the rest of your code is accurate, and then go back and try to configure this external timebase. 
Happy Holidays! -Jeff P.

0 Kudos
Message 4 of 6
(2,302 Views)
Jeff, sure, I'll give your suggestion a try; by the way,
do you know where I can get a hold of the help file that
you mentioned?

Thanks again, and happy holidays to you too.
0 Kudos
Message 5 of 6
(2,296 Views)

It is called Traditional NI-DAQ Function Reference Help.  I normally access it through the start menu of Windows

Start --> Programs --> National Instruments --> NI DAQ --> Traditional NI-DAQ Function Reference Help

OR

You can just browse to it.  It is a little different depending what versoin of DAQ you have, but it will be something like the following:

C:\Program Files\National Instruments\NI-DAQ\Docs\nidaqpc

-Jeff P

0 Kudos
Message 6 of 6
(2,288 Views)