gen voltage update.vi: can only run it once?

[SusanL]

Hello, 

I have a problem running the Gen Voltage Update.vi example. I am sure it is something stupid, but I can't figure out what. 

I am trying to get my pci-6071e card to trigger an external device (a Master 8 stimulator). This trigger will eventually become the main start experiment trigger as part of a larger vi, but for now I am just checking if I can get the lights on the Master8 to switch on by sending a signal from Labview. 

I tried to use the Gen Voltage Update.vi example to send a 5V pulse. I use an SCB100 and connected the signal to pin 20 (AO 0) and 23 (AO GND). When I pressed the run button on this vi, everything worked as it should: the M8 lit up and there where no error messages. Happy with the results, I tried to do it again, but this time the Master8 did nothing. I still got no errors from Labview. I restarted the PC, and tried again: after the first time running the trigger worked, but not when I tried another few times. 

I used to use the counters to trigger the Master8, but I need both of them to control data acquisition this time. 

Any ideas of what is going on, or alternate strategies would be much appreciated. 

[Dennis_Knutson]

Obviously, after you run the VI, the DAQ output is fixed and you would have to change the output back to 0 if you are trying to trigger something. You aren't under the impression that the DAQ output automatically returns to 0 are you?