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Cognex CDC Series Camera Description
Cognex MVS-8100D and CDC Cameras Hardware Manual
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Installation of trigger and strobe devices is discussed in
Trigger Input Features
The trigger input is used to initiate the acquisition of an image from the camera. A pair
of connections, and Trigger–, provide optically isolated trigger inputs.
The schematic of the external trigger input circuit is shown in Figure 28.
Figure 28. Trigger input schematic
To activate a trigger, between 5 and 24 V peak-to-peak must be applied to the
terminals. Cognex software provides methods to enable triggers and to specify the
following trigger properties:
•
The polarity of the trigger pulse. That is, whether the image acquisition occurs on a
rising or falling pulse.
•
An acquisition delay period after acceptance of the trigger pulse. This feature
allows each image acquisition to be delayed by a specified number of
microseconds to take into account, for example, a light source’s warm-up period,
or the amount of time for an object to come into the camera’s view on a moving
assembly line.
The next two trigger properties allow for noise spikes to be filtered out and not treated
as trigger pulses.
•
The width of the trigger pulse. That is, the minimum duration of the pulse to be
considered a valid trigger.
•
The period of the trigger pulse. That is, how long to expect between trigger pulses
for a pulse to be considered valid.
Opto-isolator
+3.3 V
Trigger –
T
1.5K
Ω
1.5K
Ω
Camera
Trigger
Input
