LabVIEW
Confusion regarding digital output connections and triggering AI
Hello all,
We recently acquired a USB-6259 DAQ (mass-term), along with 2 BNC-2090A rack mountable interfaces. We are also using LabView 8.2. What I would like to do is to create a VI that does the following:
1. Generates a single TTL pulse, which is used to trigger an electical stimulator
2. At the same time as generating a TTL pulse to trigger the stimulator, I would like the VI to trigger finite data acquisition. Specifically, I need to acquire a user-defined number of samples both before
and after the trigger.
3. I need to have the VI do the above 2 items multiple times, separated in time by a user-defined period of time (e.g. every 10 seconds, generate a TTL pulse / triggered AI data acquisition; do this 10
times)
My confusion lies with my unfamilarity with digital output in general, and the terminology that goes with it. I keep seeing reference to counter channels, but I have no experience with them, and am not sure if I need them. I have searched the forum, the NI site, as well as example files for help, but due to my what I have found has just utterly confused me (probably cause I don't know what exactly to look for, terminalogy speaking). So firstly, I am uncertain about what part of the DAQ/spring terminal block on my rack mount accesory to use. For Step 1, would I use one of the digital lines (e.g. P0.2) or one of the PFI ports (e.g. PFI 2)? From what I gather, I would need to use only a DAQmx Reference Trigger in my VI, is that correct? Also, as I need the time between each TTL pulse / triggered AI data acquisition to be defined, would I need to use a counter output channel, or can I control the timing another way (like DAQmx Timing)? I apologize if this message is confusing......I don't have an engineering background, so I was confused writing this! 
Thank you in advance.
