Exposure Time Control Modes; Exsync Controlled Operation - Basler A500k User Manual

Basic Operation and Features

3.2 Exposure Time Control Modes

cameras can operate under the control of an external trigger signal (ExSync signal) or can
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A500
operate in "free-run." In free-run, the camera generates its own internal control signal and does
not require an ExSync signal.

3.2.1 ExSync Controlled Operation

In ExSync operation, the camera's frame 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. You should refer to the manual supplied with your frame grabber board to
determine how to set up 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 frame rate. ExSync can be periodic or non-periodic.
When the camera is operating with an ExSync signal, it has three modes of exposure time control
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 not relevant. The frame is read out and transferred on the rising edge of
ExSync (see Figure 3-4).
ExSync
Figure 3-4: 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 frame is read out and transferred on the rising edge of
the ExSync signal (see Figure 3-5).
ExSync
Figure 3-5: ExSync, Level-controlled Mode
3-4
PRELIMINARY
ExSync Period
Exposure
ExSync Period
Frame Readout
Exposure
Frame Readout
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Basler A500