Triggering at 50ms per division and below

[Lestraveled]

First, I would like to congratulate JYEtech on an excellent device. The DSO138 is well thought out, well executed, and has great performance for the money.

I purchased my DSO138 recently through Amazon and per your PDF file it is authentic. The firmware is 113-13801-61.

Triggering
- It appears that there is no active triggering at 50 ms per division and below. The display simply free runs. Is this correct or do I have a problem with my device?

- At this time is there any way to trigger the DSO138 in single sweep mode below 20 ms/Div?

- In a previous thread Jyetech said that they were going to implement triggering at 50ms and below in a future firmware release. Approximately, when might this happen? (Later this year, next year....)

I would like to encourage Jyetech to implement, at least, single sweep triggering at the slower sweep speeds. This feature would add great value to the DSO138.

My application is a Revolution Per Minute (RPM) display for a personally built wind mill power system. The DSO138 would generate a histogram of the propellers speed. The DSO138 could be set to begin recording is the RPMs exceeded a certain speed, if it had triggering at slow sweep speeds.

Thank you

[Lestraveled]

OK
I am guessing because of your non reply that there is no active triggering at 50ms/div and below. The display simply free runs............ That's OK, I can use the OK button to toggle between run and hold to trigger recording and to stop it. Would anyone like a schematic on how to do this??

[jye1]

The issue of trigger at slow timebase has been fixed on DSO Shell (the new firmware is pending to release ). Will do the same on DSO138 a little later.

[gyro]

Hi JYE,

I have just read your reply in this post:

http://www.jyetech.com/forum/viewtopic.php?f=18&t=1182

Quote: " Due to wide spread counterfeits we stopped revision/update for DSO138."

I hope this doesn't mean that you are going back on your commitment to fix the 50ms/div and below triggering problem?

If you are planning to stop updates then please also remove the 'Counterfeit' warning screen as it is annoying to genuine DSO138 owners and slows down startup.

Many thanks,

Chris

[jye1]

@ gyro: We will still do the fix as promised. The message will be removed too.

[gyro]

Thanks very much, you had me worried there.

[daved]

I also found that the trigger circuit works at 20msec or faster, but not at 50msec or slower. Am looking at signals in the 1 - 10Hz range. Would also be interested in a fix, can something be done with the circuit at pin 13 of the op amp, such as increasing C9?

[gyro]

Unfortunately it is a software limitation that we need JYE to fix, not hardware.

[jye1]

Very sorry for the long long delay. We finally got some time to have this done. It was not officially released yet. But we would like friends here to test it before final release. In this version trigger under 50ms or slower was corrected. The fake product warning message was removed. Thank you everyone!

113-13801-065.rar

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[gyro]

Hi jye,

Thanks very much for finding the time to make this release.

Triggering now seems to work on slower timebase settings but I think you have introduced a bug...

Repeated pressing or holding of buttons seems to crash the s/w. This can happen during selecting different settings and changing them, or, much easier to reproduce, holding down the + or - buttons to move the vertical position of the trace or change the trigger level.

When the crash occures the screen goes to a startup screen. This has the same format as the second (white background) startup screen, but now with a BLACK background, 'DSO138' in Red and your web address, logo, Chinese text etc in Blue. This screen stays locked indefinitely - until power is removed.

Hopefully this will be an easy bug for you to reproduce and locate. I found that it happens both on the slow timebases and also on 50ms/div and faster. It also happens in both 'Running' and 'Hold' states.

I hope that you can fix this easily as the triggering on the slow timebase is a really big improvement to the instrument, (losing the 'fake' screen is really nice too!).


Just a gentle reminder of one other bug that I reported a long time ago: http://www.jyetech.com/forum/viewtopic.php?f=18&t=796
I really don't want to push my luck or delay the update release with this one as it is more of an irritation than preventing functionality.

Thanks again for your effort to implement the slow triggering function!