Basler L800k, User Manual, Page: 44 / 168

Operation and Features
3-4 BASLER L800
k
Draft
3.4 Exposure Time Control Modes
L800 k
series cameras can operate under the control of an external trigger signal (ExSync) or can
operate in “free-run.” In free-run, the camera generates its own internal control signal and does
not require an ExSync signal.
3.4.1 ExSync Controlled Operation
3.4.1.1 Basics of ExSync Controlled Operation
In ExSync operation, the camera’s line rate and exposure time are controlled by an externally
generated (ExSync) signal. The ExSync signal is typically supplied to the camera by a frame
grabber board via the Camera Link cable. You should refer to the manual supplied with your frame
grabber board to determine how to setup the ExSync signal that is being supplied to the camera.
When the camera is operating under the control of an ExSync signal, the length of the ExSync
signal period determines the camera’s line rate:
The ExSync signal can be periodic or non-periodic as required.
When the camera is operating with an ExSync signal, three modes of exposure time control are
available: edge-controlled mode, level-controlled mode and programmable mode.
• In ExSync , edge-controlled mode, the pixels are exposed and charge is accumulated over
the full period of the ExSync signal (rising edge to rising edge). The falling edge of the
ExSync signal is irrelevant. The line is read out and transferred on the rising edge of ExSync.
(see Figure 3-2).
The edge-controlled mode will give you the best performance in terms of signal-to-noise ratio.
Figure 3-2: ExSync, Edge-Controlled Mode
• In ExSync , level-controlled mode, the exposure time is determined by the time between the
falling edge of ExSync and the next rising edge. The pixels are exposed and charge is accu-
mulated only when ExSync is low. The line is read out and transferred on the rising edge of
the ExSync signal (see Figure 3-3).
Figure 3-3: ExSync, Level-controlled Mode
Line Rate
1
ExSync signal period
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