How can I trigger the grab function on PCI-1422 externally?

[MLezius]

I have a Basler 103-1k digital line scan camera connected to a PCI 1422 frame grabber. I want to trigger multiple line scans externally at a rate of 1 kHz. Up to now it is possible for me to use the snap routine, but then the frame rate remains well beyond the capabilities of both, the camera and the frame grabber, because the camera is initialized for every shot. Repetition rate reaches about 500 Hz. I want to use the continous grab function, but I can't find out how to trigger line frames from an external trigger. The trigger only seems to starts the acquisition, but then the camera always runs without any phase lock to my external trigger. Where is the trick?

[Brent_R]

Instead of using the Snap function, it would probably be better to use a Grab or Ring acquisition. We have a good example on the website that shows how to trigger each line from an external source (often an encoder).

http://zone.ni.com/devzone/explprog.nsf/6c163603265406328625682a006ed37d/f2799dc12a94be2586256a79006985ce?OpenDocument

The key here is the two IMAQ Trigger Config VIs. One of the VIs configures the acquisition to start each frame based on a trigger and the second configures the line acquisition rate. This example uses the encoder feedback from a motion system to trigger each line, however you could easily remove the motion code and supply a trigger from the source of your choice. You can disable VHA to get fixed height images. Also, you can re
move the "trigger each buffer" VI, so that you get continuous, fixed size frames that are controlled only by the line rate.

Also, take a look at the LL VHA Ring example that ships with NI-IMAQ. Add an IMAQ Configure Trigger with the parameter "trigger each line" to specify the source of the line rate control.

Regards,

Brent R.
Applications Engineer
National Instruments