Vertical Synchronisation of video signal

[dotzel]

Hi,
we want to use a JAI CV-M50 in connection with NI 1409 for vision application. The CCD and 1409 is triggered by an ext. trigger simultaniously in different frequences. With 25 Hz the image is ok, with 24 Hz the image is moved vertically by approx. 100 lines , with 23 Hz we get a greater deviation, etc. With 19 Hz the image is OK again. It seems that the NI 1409 doesn't recognize the vertical blanc of the video signal, even it is demanded by the imgsnap -function.

[BruceAmmons]

I am not sure why this would happen, but I saw a similar problem in a digital camera once. The solution I found was to reduce the height of the image by a couple of pixels in MAX. This way, the image finished acquiring before the vertical sync signal occurred.

Bruce