Sigma LBA-400, LBA-710, LBA-714PC, LBA-300, LBA-712, LBA-708, LBA-500PC, LBA-700 manual Lba-Pc

•Trigger Out: If your laser is a pulsed type, and you would like the LBA-PC to provide an output pulse that will cause the laser to be fired, use this setting. See Trigger Out and Interval and Trigger Out Delay.

•Video Trigger: With this mode selected, the input from your camera is continuously monitored, and when a laser pulse is detected, the frame is captured. The pulse detector has a programmable threshold that is settable in the Video Trigger Level edit control. The level setting is always in raw digitizer counts. A suggested trigger level value, that will not detect noise yet remain reasonably sensitive, is the second lowest level.

•Trigger In: If your laser can provide a compatible trigger input pulse to the LBA, then you can use that pulse to synchronize the capture of your video frame. In general, this technique is inferior to the preceding Video Trigger mode. Its only advantage would be to allow you to capture an event that occurs independently of other things that might be occurring in the video frame that preclude the use of Video Trigger. See Polarity.

Figure 20

The other settings operate and apply as follows:

•Trigger Out: Applies to Trigger Out and Video Trigger modes. Output pulses from the LBA-PC can be programmed to output Always, or only when the frame grabber is sampling video While Running. i.e., beginning when you click Start!, ending when you click Stop! Note: The output trigger pulse is always positive and its pulse width is fixed (see Specifications).

•Interval: Applies to Trigger Out and Video Trigger modes. You can program the rate at which the LBA will produce trigger output pulses. The rate is based upon the camera frame rate. The value entered in this edit control specifies how many frames will occur for each trigger pulse generated. A setting of 1, will output a trigger pulse once for every frame of the camera; 2, will output a pulse on every second frame; 3 every third; and so on... Divide this setting into the camera frame rate to compute the rate at which the LBA will output trigger pulses. i.e., a 3 will cause a 30 Hz frame rate camera to fire a laser at 10 frames per second.

•Trigger Out Delay: Applies to Trigger Out and Video Trigger modes. If this item is not checked, the trigger output pulse will occur at the same time as the camera’s vertical sync, i.e. at the start of each video frame. For many CCD cameras, this is not a good time to receive a laser pulse. If you check this item, the trigger output pulse will be delayed to a time near the middle of the video frame, or field, if the camera is interlaced.

•Polarity: Applies to the Trigger In mode only. The LBA response to a trigger input is edge sensitive. You can program the response to the input trigger pulse to be either Positive, rising edge sensitive, or Negative, falling edge sensitive.

Operator’s Manual	63	LBA-PC
Doc. No. 10654-001, Rev 4.10