06-03-2009 01:35 PM
I need some help with a VI that should measure the separation time between a trigger signal & incoming pulses. I am using LabVIEW 8.5 with a PIXI chassis & a PXI-6608 card. I have a delay generator that gives me 3 pulses at programmable times going into a BNC-2121 block then going into the PXI chassis.
I have the DAQ Assistant set up to measure two-edge separation using Counter_0 thru Counter_7. For Counter_0, Signal_1 comes from the Digital Trigger on the BNC-2121 & Signal_2 comes from the delay generator Channel_1. According to the NI-DAQmx help, this corresponds to PFI37 & PFI38 respectfully.
The Digital Trigger also goes to Counter_1 Signal_1 (PFI33) & Signal_2 (PFI34) coming from Channel_2 of the delay generator. The other counters are set up in the same fashion.
When I trigger the delay generator, I can see the 3 pulses on an o'scope. When I connect the signals to the counters it does not work as expected. I have to trigger the delay generator 3 times to get the timing for all 3 two-edge separation measurements...
Any suggestions?
06-03-2009 04:20 PM