simultaneous counting with external clock

[CorrosionFan]

Dear All,

I am trying to do simultaneous event counting with an external sample clock.  I can easily get one channel to work well with the sample clock, but I can't seem to be able to get the second one to work simultaneously.  I think the answer lies in triggering, but thus far I have not been able to get that to work.  I am using a PCI-6010 board and programming in Labview 8.0.  I have attached my code below which does the measurement sequentially for each counter.  Thanks for all of the help.  FYE, the event rates vary from 1e3 /s to 1e6/s and I use the sample clock up to 100 KHz.

Thanks for all of the help

[Paul_C.]

Hi CorrosionFan,

I would recommend, in addition to using the same external sample clock source, using an arm start trigger to start both counters at the same time.  I would also recommend using the 80MHz timebase as you're source.  This will allow you to arm both counters (essentially starting them) at the same rising edge of the 80MHz timebase.  This can all be done through a DAQmx trigger property node.  Here is a picture of the property node I'm referring to:


If you need any additional help or information about arm start triggers, I would highly recommend taking a look at the 6010 help file which can be downloaded here [download no longer available].

I hope this helps,
Paul C.

Message Edited by Paul C. on 09-17-2007 04:06 PM