Photon Focus MV1-R1280-50 Series, User Manual, Page: 35 / 103

5.2 Trigger and Strobe
Exposure time >= read out time
When the exposure time is equal or bigger than the read out time then the maximal frame
rate depends only on the exposure time (see Fig. 5.2).
MaxFrameRate = 1 / ExposureTime
T r i g g e r
E x p o s u r e
R e a d o u t
F r a m e < n + 1 >
E x p o s u r e T i m e
R e a d o u t T i m e
F r a m e < n >
Figure 5.2: Read out timing 2: exposure time equal or bigger than read out time
5.2 Trigger and Strobe
5.2.1 Introduction
The start of the exposure of the camera’s image sensor is controlled by the trigger. The trigger
can either be generated internally by the camera (TriggerMode=Off / free running trigger
mode) or by an external device (TriggerMode=On / external trigger mode).
This section refers to the external trigger mode if not otherwise specified.
In external trigger mode, the trigger can be applied through the power supply connector of
the camera or through a software command (see Section 5.2.2). The trigger signal can be
configured to be active high or active low. When the frequency of the incoming triggers is
higher than the maximal frame rate of the current camera settings, then some trigger pulses
will be missed. A missed trigger counter counts these events. This counter can be read out by
the user.
The exposure time in external trigger mode can be defined by the setting of the exposure time
register (camera controlled exposure mode) or by the width of the incoming trigger pulse
(trigger controlled exposure mode) (see Section 5.2.4).
An external trigger pulse starts the exposure of one image. In Burst Trigger Mode however, a
trigger pulse starts the exposure of a user defined number of images (see Section 5.2.7).
The start of the exposure is shortly after the active edge of the incoming trigger. An additional
trigger delay can be applied that delays the start of the exposure by a user defined time (see
Section 5.2.5). This often used to start the exposure after the trigger to a flash lighting source.
5.2.2 Trigger Source
The trigger signal can be configured to be active high or active low by the TriggerActivation
(category AcquisitionControl ) property. One of the following trigger sources can be used:
Free running The trigger is generated internally by the camera. Exposure starts immediately
after the camera is ready and the maximal possible frame rate is attained, if
AcquisitionFrameRateEnable
is disabled. Settings for free running trigger mode:
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