Exposure Time Control Modes; Exsync Controlled Operation; Basics Of Exsync Controlled Operation - Basler L800k User Manual

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Operation and Features

3.4 Exposure Time Control Modes

series cameras can operate under the control of an external trigger signal (ExSync) or can

L800

operate in "free-run." In free-run, the camera generates its own internal control signal and does

not require an ExSync signal.

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:

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

3-4

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ExSync signal period

Draft

BASLER L800

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