image acquisition using 1424

[mps]

Hi, I was sure that I would find an answer to my question by browsing the archive of previous posts, but I didn't, so here is my problem.

I am using a duncantech cac to acquire images...1 image every 250ms. I have a trigger that triggers the camera to capture an image and send it to the framegrabber 1424 card. My question is this, how can i tell when the framegrabber has been sent a new image?? I can't connect the trigger to the framegrabber card.

[Brent_R]

There are several ways to determine when a frame has been acquired.

1) When you call the acquisition function (ex. IMAQ Grab Acquire), the function will simply wait until a frame is ready and then return the image. You will need to set the timeout value to be long enough to accomodate your trigger period, but you do not need to perform any kind of polling.

2) You can use occurences to make your program wait at a certain point until a frame is ready. Once the occurence is fired, call the acquisition function and a frame will be returned immediately.

3) You can call the IMAQ Status function in a loop to check the number of the last valid buffer. When this number increments, a new frame is available.

In general, if the camera is already being triggered di
rectly, then the board does not require a trigger and no special programming techniques are necessary.

Regards,

Brent R.
Applications Engineer
National Instruments

[Larry Liu]

Dear Brent,

I got the same problem.

I have written a short program to start acquiring one image (timeout set to 10s in MAX) in LabVIEW.

After that, I also send out the trigger signal to the camera via the parallel port in LabVIEW.

However, I am getting an alternatively white (with black edges) and black image (completely black).

For more info, pls refer to http://forums.ni.com/ni/board/message?board.id=200&thread.id=25374

I have attached my program, please kindly take a look and let me know if i made any mistakes.

thanks so much...

Larry