Specifications

Version 1.1 rev Jan 2013
Page 66
iXon Ultra
, Features and Functionality
3.5.1 - Triggering options in Frame Transfer (FT) mode
3.5.1.1 - Internal Triggering (FT)
This is the simplest mode of operation, in that the camera determines when the exposure happens. By monitoring the
Fire output, the user can determine exactly when the camera is “exposing”.
When the camera is idle, it is running the Idle Keep Clean Cycle described previously. On receipt of the Start command
from the PC, the camera completes the current Keep Clean Cycle and then performs sufcient vertical shifts to ensure
that the Image and Storage regions are completely free of charge. The camera then starts its real exposure sequence,
for which the timing sequence is illustrated in the gure below.
The rst thing to notice is that the Fire output is high for much of the time. This is because there are no Keep Clean
Cycles running between each acquisition, and hence the exposure time starts on completion of the transfer of the
Image area into the Storage area. This also has the consequence that the exposure time and the cycle time are closely
linked. We have dened the exposure time as the time during which there are no vertical shifts occurring, which also
corresponds to the time during which the Fire output will be high. The other point to note is that the exposure time
overlaps the read out of the image.
Figure 24: Internal Trigger in Frame Transfer mode