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Kestrel/USER-MANUAL/REV1.1/08-20
9.2 Triggering Modes and Pixel Clock Rate
The cameras triggering mode can be toggled from the “Trigger” tab, shown in Figure 7. A
summary of the triggering modes is below:
Live – ITR
: The is the default mode of the camera, using the internal trigger, Integrate then
Read. In this mode, the camera will run at the highest possible frame rate given the current
exposure time set. The frame period will be:
Frame period = Exposure time – Readout time
Using an exposure time of 1.93ms with a 10MHz pixel readout speed, the maximum frame
rate of 510.5Hz in full frame resolution can be achieved.
Live – FFR:
This is fixed frame rate mode. In this mode, the user will be allowed to set a
fixed frame period. If an exposure time set is greater than the maximum exposure time for
the set frame period, the exposure time will dominate, and the frame period will be
increased.
Ext Triggered:
This mode sets the camera into external trigger mode. Enabling the external
trigger will open the trigger polarity options (rising or falling edge).
There is a slight drop off in the maximum frame rate in external trigger mode. The maximum
frame rate achievable in full frame resolution is roughly 510.5Hz.
In ITR mode, the camera is in full control of the trigger and is aware that repeated frames will
be requested one after another as quickly as possible. Therefore, the vertical clear is
skipped before the start of each acquisition. In external trigger mode, the camera has no
knowledge of when the next trigger will arrive, and hence conducts the vertical clear before
the beginning of the next exposure. This vertical clear accounts for the slight drop in frame
rate in external trigger. The lack of the vertical clear in ITR mode also means that the
effective exposure time in ITR mode is closer to exposure time + readout time.
Btn. Triggered:
This mode enables the user to capture a single exposure. The
“Single
Exposure”
button in the GUI will become active and clicking it will trigger an exposure time
and capture.
Figure 7: Trigger Tab.
