View Full Version : External Hardware Trigger

December 17, 2015, 12:26:42

I am newbie on using DMK23U618 camera and need help on external hardware triggering.
I have a pulse generator which generates trigger @100Hz rate with pulse width of 65usec. Output voltage of trigger is 3.3V. I am trying to use IC capture 2.4 tool to capture images automatically.

Could you please help.


Stefan Geissler
December 17, 2015, 13:09:30
The only problem I see, is:
- 3.3 V is too less. you need at least 5V.
- 100Hz triggering is fine, if the exposure time is short enough. But you wont be able to save 100 single image files per second to hard disc, because the hard discs are not fast enough. You may use AVI Capture instead. Start the camera, enable the trigger (The square signal labeled button in one of the toolbars), configure AVI capture and start AVI Capture. Then start your trigger generator.

December 18, 2015, 15:17:52
Thanks a lot for the suggestion. Now setup works as expected.

December 21, 2015, 12:47:30
I have further question on triggering. When I have set the free running trigger at the rate of 10FPS, I was expecting IC Captured 2.4 would capture 600images, however I got only 592. There were few frames missing in free running mode. Also similar behavior observed in external trigger mode.
In External Trigger I/O whitepaper few parameters are mentioned Like: tdmin, frame rate. Could you please help me to set these values using IC Capture as no details are provided. Also tro time is it is seconds? Please help.

Stefan Geissler
December 21, 2015, 13:21:07
I suppose, you use AVI capture. In this case, you must expect, that not all frames are written by the file writer into the file. This also is a timing issue, when then file is created and closed.

If you start AVI capture and then start your trigger machine for 600 frames, all 600 frames should be written into the file.

December 21, 2015, 13:50:49
Hi Stefan,

Thanks for quick response.

I tried with free running mode avi capture. For 1minute duration, frames captured are as below.
@10fps --> 592 frames were captured
@60fps --> 3594 frame were captured
@50fps --> 2957 frames were captured

Is it that length of USB 3.0 cable impacts frame capturing. I am using around 16inch cable. I am just guessing.

Thank You.

Stefan Geissler
December 21, 2015, 14:36:42
The problem is, if the camera is free running and you start AVI capture, you do not know, how long it takes, until the file is created and ready to receive images.

16 inch is a nicle little cable. But this is not a cable issue. It is an AVI capture issue. It is caused by computer. And there is no solution for this.

If you write a software and count the incoming images only, then you will receive better results.

December 22, 2015, 07:58:21
In, Trigger IO help file(wp23trigo_1.2.en_US.pdf), t read out time is = 1/frame rate. What is this frame rate and how to set this using IC Capture. Is this same as trigger rate or fps.


Stefan Geissler
December 22, 2015, 09:54:04
The frame rate specifies how many frames the camera sends per second. The abreviation "fps" is often used for this. In IC Capture is an "fps" labeled combo box on the right side of the device toolbar.