8.Features
© China Daheng Group, Inc. Beijing Image Vision Technology Branch 110
8.2.6. External Trigger Acquisition and Configuration
External trigger acquisition configuration
The camera supports external trigger acquisition mode. Three steps followed should be ensured:
1) Set the Trigger Mode to ON.
2) Set the Trigger Source to Line0, Line2 or Line3.
3) Connect external trigger signal to Line0.
If the Trigger Source is set by Line2 or Line3, it should be ensured that the corresponding Line is set as
Input.
for more information of the programmable GPIOs.
External Trigger acquisition features
The relative features about the camera's trigger signal process are illustrated below:
1) The polarity of lines can be set to inverted or not inverted, and the default setting is not inverted.
2) Improper signal can be filtered by setting appropriate value to trigger filter. Raising edge filter and
falling edge can be set separately. The range is from 0 to 5000 us. The default configuration is not use
trigger filter.
3) The time interval between trigger and exposure can be set through the trigger delay feature. The range
of time interval covers from 0 to 3000000μs. The default value of trigger delay time is zero.
The features, like trigger polarity, trigger delay and trigger filter, can be select in the GalaxyView.
The camera's trigger source Line0 uses opto-isolated circuit to isolate signal. Its internal circuit
delay trigger signal and rising edge's delay time is less than falling edge's. There are a dozen clock
cycles delay of rising edge and dozens clock cycles delay of falling edge. If you use Line0 to trigger
the camera, the positive pulse signal's positive width will be wider (about 20-40
μs) and the
negative pulse signal's negative width will be narrower (about 20-40
μs). You can adjust filter
parameter to accurately filter trigger signal.
There is small difference among there models of MER-U3
camera. These camera’s different time intervals
are shown below:
Camera model
GPIO delay time
opto-coupler delay time
MER-031-860U3M/C
Non-
overlap/Overlap: 4μs
Non-overlap/Overlap: 8-
12μs
MER-031-860U3M NIR
Non-
overlap/Overlap: 4μs
Non-overlap/Overlap: 8-
12μs
MER-041-436U3M/C
Non-
overlap: 0.16μs
Overlap: (0.16~4.08) μs
Non-
overlap: 4.16~8.16μs
Overlap: (4.16~12.08) μs
MER-050-560U3M/C
Non-
overlap/Overlap: 4μs
Non-overlap/Overlap: 8-
12μs
