Page 107 of 120

Camera modes of operation 107
Fixed line scan rate with frame trigger mode
In a fixed line scan rate mode with a frame trigger, the line scan rate is controlled
by the period of the exposure signal. The frame rate is variable, and controlled by
ELIMAINYA2R0Y05 frametrigger
the frequency of the external frame trigger; the external trigger period, however,
must always be greater than the total time of the number of lines captured. The
camera can use internal or external exposure time controls. The frame size is
determined by the line number in the vertical timing specified in the DCF.
The number of lines per frame is fixed and determined by the vertical timing of
the DCF. The grab starts on the rising edge of the frame trigger signal.
The required connections when using this mode are external trigger signal to frame
grabber, exposure signal to the camera, and the video and synchronization signals
from the camera to the frame grabber.
The following diagram illustrates the timings for fixed line scan modes with frame
triggers:
camera
video signal1
pixel clock*2
exposure signal
sync
frame grabber
external trigger
R M exposure
P 19 line valid
exposure
time
video
video
video
valid
valid
valid
* optional signal
1. analog or digital
2. internal or external
    "