counting digital events for a finite time

[bog]

I'm trying to implement the 2424.vi using a PCI-6221 and a BNC-2110 in Labview 8.0. 

http://zone.ni.com/devzone/cda/epd/p/id/1672

 My goal is to use a hardware timer to control the length of time that the counter collects TTL pulses.  For the implementation, I am using ctr0 as the counter and ctr1 as the timer. On the BNC-2110 I have the PFI-8 wired to accept the TTL pulses.  I've also jumpered the CTR1OUT to PFI-9 (output pin of gating counter to gate pin of input counter). 

The problem I'm having is that the ctr0 does not seem to recognize the gate signal from the ctr1 output. When I set the Start Trigger Source to dev1/pfi9, I get timeout errors.  I can get the vi to work by setting the Start Trigger Source to either dev1/pfi8 or dev1/pfi4.  pfi8 is the ttl source, so this isn't surprising, but it also isn't what I want to do.

Any advice or an alternate method to accomplish the same goal?

[Raajit_Lall]

bog,

The start trigger source actually needs to be the actual hardware timer trigger signal.  You have already hard wired the CTR Output to PFI9.  This start trigger source actually needs to be your trigger signal, and not the signal going to the gate.  Could you please try that and see if that helps?

As the comments suggest, the bottom task will generate an output pulse that controls the gate of the counting task.  It is started by a digital trigger and generates a single pulse for the time specified by the user.  The trigger source for this task needs to be your actual trigger signal.

Hope this helps.

Regards,