Exposure Modes - Basler ace acA640-90gm User Manual

7.4.3.2

Exposure Modes

If you are triggering the start of frame acquisition with an externally generated frame start trigger
(ExFSTrig) signal, two exposure modes are available: timed and trigger width.
Timed Exposure Mode
When timed mode is selected, the exposure time for each frame acquisition is determined by the
value of the camera's Exposure Time Abs parameter. If the camera is set for rising edge triggering,
the exposure time starts when the ExFSTrig signal rises. If the camera is set for falling edge
triggering, the exposure time starts when the ExFSTrig signal falls. Figure 36 illustrates timed
exposure with the camera set for rising edge triggering.
ExFSTrig Signal
Fig. 36: Timed Exposure with Rising Edge Triggering
Note that if you attempt to trigger a new exposure start while the previous exposure is still in
progress, the trigger signal will be ignored, and a Frame Start Overtrigger event will be generated.
This situation is illustrated in Figure 37 for rising edge triggering.
ExFSTrig Signal
Fig. 37: Overtriggering with Timed Exposure
For more information about the Frame Start Overtrigger event, see Section 10.10 on
For more information about the camera's Exposure Time Abs parameter, see Section 7.5 on
page 87.
Basler ace GigE
ExFSTrig Signal Period
Exposure
(duration determined by the
Exposure Time Abs parameter)
Exposure
(duration determined by the
Exposure Time Abs parameter)
Image Acquisition Control
This rise in the trigger signal will be
ignored, and a Frame Start Overtrigger
event will be generated
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