Can your PCI-4451 generate an interrupt (DAQ event) that can be used
to tell your application when it has completed its 2 second sweep?
That would be the best way. Set up the card to sweep once every two
seconds on it's own and then have it signal the PC to collect the
sweep with a DAQ event. This would be similar to telling an o-scope
on a GPIB interface to do a two second long sweep and triggering it
from the host PC and telling the host PC to wait on the SRQ when the
scope is done with it's sweep.
If not, the best resolution you will probably get is about 10mS using
a standard LV timer. You could implement a MCI multimedia timer via C
code which is more precise (1mS) but it will eat up a lot of CPU.
Interrupts or DAQ events will be m
uch better because they are very
precise and don't eat up any CPU.
If you can't do this, perhaps you can use some external dedicated
hardware to generate an interrupt on your PC or something through
another I/O device on your PC, like the control lines on a parallel
port can be used to generate interrupts if you write the code for it.
This would have to be done in C though and would need to be on an O/S
that allows you to generate interrupts from a regular user
application, i.e. Win95 or 98 would probably work wheras NT would not
unless you wrote your own kernel mode device driver.
Douglas De Clue
ddeclue@bellsouth.net
wisam wrote in message news:<506500000005000000A38C0000-1027480788000@exchange.ni.com>...
> Hi :
>
> may be you don't understand me .... i want to use timer to controll on
> my PCI-4451 ..
> what i mean if I Create a sine sweep in my application using PCI-4451
> all the time this sine sweep run .... what I want every 2 scound I
> want to measure the inp
ut
