Hello,
The best way to determine this is to run one of the examples for triggering shipped with NI-IMAQ.
You will find an example to perform a simple trigerred image acquisition in the Help Menu of LabVIEW, then select "Find examples... >> Hardware I/O >> IMAQ >> I/O signals >> HL Triggered Snap.vi"
This example is compatible for PCI/PXI-1409 and IMAQ-a6822 hardware.
I hope it will help.
Regards.
Matthieu Gourssies
National Instruments France