Author Topic: Question about triggering  (Read 5567 times)

alexchang

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Question about triggering
« on: February 10, 2020, 01:25:41 PM »
Hi all,

I've been using my chronos 1.4 in the lab to look at some pulsed plasma discharges. I let the camera record and I use the falling edge of a pulse to trigger the record end on the camera and save the previous three recorded frames. I'm just wondering if there's a way to determine the time between the recording of the frames and the trigger to stop.

The event I'm looking at is a plasma discharge that evolves over 100us, I'm recording it at 63us between frames so I only get 1 frame per discharge, but I want to vary my end of recording signal to get frames at different parts of the discharge.

I've attached a graphic to better explain my problem.

Thanks for any ideas!

skronstein

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Re: Question about triggering
« Reply #1 on: February 10, 2020, 02:52:27 PM »
For clarification - Do you need sub-frame resolution (time in less than 1 frame period), or is whole-frame resolution good enough? From the pdf you attached, it looks like you do need sub-frame resolution.

There is a feature called the Text Overlay that can be enabled under the saved file Settings menu, accessible from the Play screen. It shows the time at which a frame was recorded, relative to the time of trigger. However, it only has whole-frame resolution.

alexchang

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Re: Question about triggering
« Reply #2 on: February 10, 2020, 05:25:47 PM »
Yes I was hoping to get sub-frame resolution by varying my trigger pulse. But I guess if the text overlay only has resolution of one frame my prospects aren't looking too good with using the record end trigger.

skronstein

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Re: Question about triggering
« Reply #3 on: February 10, 2020, 06:59:45 PM »
You could enable Frame Sync output and use an oscilliscope to measure the time between the frame and the trigger. When Frame Sync Output is enabled, the camera will switch IO 1 and/or 2 to high while the image sensor is exposed, and low when it is not exposed.