Basler A102f, Руководство пользователя

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Basic Operation & Standard Features
3-14
BASLER A102
f
DRAFT
3.3 Trigger Ready Signal
The maximum frame rate for the camera can be limited by any one of three factors:
• The amount of time it takes to read out a captured image from the CCD sensor to the frame
buffer.
• The amount of time it takes to transmit an image from the frame buffer to the PC via the IEEE
1394 bus.
• The exposure time setting.
The camera automatically recalculates the maximum frame rate any time a setting that effects one
or more of these factors is changed. For example, the camera will recalculate the maximum frame
rate if you change the exposure time, the size of the area of interest, or the packet size.
The camera will use the calculated maximum frame rate to generate a “trigger ready” (TrigRdy)
signal. The trigger ready signal indicates the earliest moment that each exposure can begin
without exceeding the maximum frame rate for the current conditions. The trigger ready signal will
go low when each exposure is started and will go high when it is safe for the next exposure to
begin (see Figure
3-6 ).
By default, the TrigRdy signal is assigned to physical output port 1 on the camera. See Section
2.5.2 for a description of the electrical characteristics of the camera’s physical output ports.
The assignment of the TrigRdy signal to a physical output port can be changed. See Section
6.7.11 for more information on changing the assignment of camera output signals to physical
output ports.
L
The trigger ready signal is not defined in the 1394 Trade Association Digital Camera
Specification. Trigger ready is a patented feature of Basler cameras that allows our
cameras to have optimized timings.
L
If you signal the camera to start an exposure when trigger ready is low, the camera
will delay the start of exposure until the next rise of the trigger ready signal. This pre-
vents you from running the camera faster than the maximum rate and avoids drop-
ping frames.
If the camera is in continuous shot mode and external triggering is disabled, the trig-
ger ready output signal will not be present.