SIGMA LBA-708 - Manual (Page 119)

Since the perfect camera has not yet been found, we advise most LBA-PC users to operate pulsed
lasers in Trigger Out mode whenever possible. Next best choice is the Video Trigger mode. These
two modes will produce the most repeatable quantitative results.
5.1.2 Trigger Type CW
The setup for CW timing is the least complex of the setups. Therefore, we recommend that you use
CW mode to verify that your camera is correctly installed and is operational. The basic CW
installation requires that you set Capture Method to Continuous, and the Capture Interval to 1.
5.1.2.1 Interlaced Cameras
In CW mode, interlaced cameras will support all available resolution settings and zooming
capabilities. The highest of these resolutions will be made up of digitized data from both the odd
and even fields. The odd and even data is assembled to form a single image. If you are
observing a rapidly changing image at high resolution, you may observe line-to-line image
breakup. Reduce your resolution to help stabilize the image. Some cameras may also exhibit an
intensity variation from one field to the next. Most interlaced cameras will yield good high-
resolution images in CW mode.
5.1.2.2 Non-interlaced Cameras
In CW mode, non-interlaced cameras will support all available resolution settings and zooming
capabilities. Most cameras will yield good high-resolution images in CW mode.
5.1.3 Type Trigger Out
Two types of Trigger Out operations are provided. They are the runs Always and the only While
Running choices. With the While Running selection, the triggering of the laser is switched on and
off by clicking Start!/Stop!. If you choose the runs Always option, then the trigger output pulses
will run continuously and independent of data collection.
5.1.3.1 Trigger Interval
The rate at which trigger output pulses occur is dependent upon the frame rate of the camera
and the specified Trigger Interval value. Specifying an interval of 1 will cause the output
trigger to run at the camera's frame rate (this corresponds to the fastest possible rate). A value
of 2 will produce an output pulse on every second video frame. A 3 will pulse on every third
frame, and so on.
Example: If you are using a 60 Hz frame rate camera and desire to produce an output pulse once each second,
program a 60 into the Trigger Interval.
Should you need a high rep rate trigger, select a camera with as fast a frame rate as possible.
(The frame rate of interlaced cameras is one half the field rate.) A Trigger Interval value of 1 will
cause an output pulse to occur once per camera frame. Thus, an interlaced camera running at a
Operator’s Manual LBA-PC
Doc. No. 10654-001, Rev 4.10
119