DSO4084B Bug report

xyz

Hi, here are some bugs that i found. My device info:



1. Adjust mem depth to >4K, in my case 64K. Set trigger to auto mode. Take a single shot of any waveform or just use run/stop. Turn horisontal position left and right to see waveform behind the screen. When trigger is set to auto mode waveform displays correctly from memory (pic. 1). Now switch trigger to normal mode and use horisontal position again. The waveform is cutted (pic. 2).



2. Set trigger to auto mode. Set time base to some large value, for example 500us. Take a single shot of any waveform (pic. 1). Decrease time base, in my case to 1us (pic. 2). You can see some line drawing issue. When one of line points is out of the screen, the line is not drawn. Drawing algorithm could use some interpolation to calculate missing point at x1 = 0 and x2 = screen width, and then draw line normally.



3. Using stopped waveform from previous point, change trigger to normal mode. Decrease time base to <=50us. Waveform is displayed incorrectly (pic. 1, 2).



4. Connect probe to device internal 1kHz generator. Set time base to 50ns, and set trigger to auto mode. Use single button (pic. 1). Then decrease time base to 20ns and use single button again (pic. 2), and so on (pic. 3)... See the waveform.



5. Set trigger to normal mode. Set time base <=20ns. Use single button. Horisontal position and time base controls are not working.

There are some other issues, but they probably exist due to problems that i listed above.
Also mem depth (sampling frequency) usage is kind different that i found in devices of other manufacturers (Rigol for example).
Now i have to force trigger on some detail that i want to see, and then eventualy zoom out to see the rest (using complete 64K mem).
It would be nice if i could do it in opposite way... I mean, that 64K mem was displayd default on entire screen width (without scrolling).
Then i could force trigger on some general data (usart frame for example), and then zoom in to see the details (using max sampling fequency available at current time base).

Hope to see some bug fixes soon...
Thank You.

xyz

Thank you for your fast reply.
Where can i find firmware change log?
It would be easier to check bug fixes if one was attached to firmware package...

xyz

I see there was firmware update (20180117). Problem #1 is fixed, but only partially. When you force trigger (single button) in auto or normal mode and use horisontal position, waveform is displayd fine... But, when you force trigger in auto mode, and then switch to normal mode without forcing the trigger again, waveform is still displayed cutted.

All other problems that i listed above still exist. Is this update suppose to fix them, or i should wait for next update? It's hard to guess without changelog

xyz

Here are some other bugs thai i found:



1. Trigger mode: auto/normal. Acquire mode: HR. Triggered waveform has some horisontal offset, ~15ns.



2. Trigger mode: normal. Acquire mode: average. Time base <=20ns. Waveform is triggered randomly and is unstable on the screen.



Also, option to set "force trig" button as "save picture" have gone from menu. That's a pity, because this was actually a good one.
Looking forward for some updates...

xyz

And another bug with the trigger... To see the problem i sugest to use some short single pulse signal every 1 second. Set trigger to normal mode. Use single button to stop the waveform. Now use run/stop button to release the waveform. From now trigger acts like it was in auto mode, even if menu still says it's in normal mode. If you change trigger to auto and then to normal again, the trigger starts working normally. Any progress with update? Thank you.

xyz

Hello. I was trying to reply earlier but i couldn't login on the forum for almost a week, and actually i still can not. I see the were some changes with login system on the forum. I'm using firefox daily. Each time i try to login everything seems fine till i'm redirect to forums main page. There is no wrong password message or anything... I'm just still not logged in. I tried to switch to edge with same result. Now i'm using internet explorer. First try to login with same result, second time... somehow i'm logged in Please inform forums admin about the problem.

Thank You amy for great news... I have immediately downloaded new firmware to see what was fixed. Almost every bug that i reported above is repaird, except these two:

2. Trigger mode: normal. Acquire mode: average. Time base <=20ns. Waveform is triggered randomly and is unstable on the screen.

And another bug with the trigger... To see the problem i sugest to use some short single pulse signal every 1 second. Set trigger to normal mode. Use single button to stop the waveform. Now use run/stop button to release the waveform. From now trigger acts like it was in auto mode, even if menu still says it's in normal mode. If you change trigger to auto and then to normal again, the trigger starts working normally.

What i also noticed with second bug is that if i switch menu from trigger menu to any other and than to trigger menu again the trigger mode displays auto.
I belive they will be fixed with next firmware update. To be honest, when i wrote my first post i didn't expect that Hantek has such a great support

Meantime i have found another bug.
Connect probe to internal 1kHz generator. Set time base to 20ns. Use single button to stop the waveform. Now increase time base few steps and see the waveform. If it is displayd fine then repeat procedure from first step. This bug shows up only from time to time and i think it is due to some specific input signal. Here are screenshots:




Again, Thank You very much for your great support.
Lookin forward for some news...
Best wishes.

xyz

Hello, here is some feedback to the latest update, and some new bugs found.

2. Trigger mode: normal. Acquire mode: average. Time base <=20ns. Waveform is triggered randomly and is unstable on the screen.

This one still exists, and only in triggering normal mode. In auto mode waveform  is stable on the screen. See screenshots.

And another bug with the trigger... To see the problem i sugest to use some short single pulse signal every 1 second. Set trigger to normal mode. Use single button to stop the waveform. Now use run/stop button to release the waveform. From now trigger acts like it was in auto mode, even if menu still says it's in normal mode. If you change trigger to auto and then to normal again, the trigger starts working normally.

This one is also  not yet repaird. And the problem is simpler than i thought... It's just that pressing "single" button allways switches trigger to auto mode.

Some new bugs:

Mem depth >4K, trigger mode normal. Connect probe to any periodic signal and set trigger level to the middle of the signal. Now move trigger level above or below your signal and use horisontal position knob. Signal i cutted. Just like in the first post  that i wrote in this thread.



Enable second channel and enable measure on that channel. When "All Measure" option is set to "OFF" the displayed values are for first channel instead of second channel. The same is with channels three and four

xyz

Hi, here is some feedback to the latest update (firmware 1.1.2(180608.0)).
Bugs that i reported above are fixed except this one:

Mem depth >4K, trigger mode normal. Connect probe to any periodic signal and set trigger level to the middle of the signal. Now move trigger level above or below your signal and use horisontal position knob. Signal i cutted. Just like in the first post  that i wrote in this thread.

xyz

Hi, I have just update my oscilloscope to the latest firmware version, 20181208.
What I noticed is that horizonatl position knob and trigger position knob are not responsive anymore.
If you turn a knob slowly then it works "almost" fine, but if you turn it a little too fast then it is not working, or even works in opposite direction.
Vertical position knobs are working fine on all four channels...

Also this one is still not repaird:

Mem depth >4K, trigger mode normal. Connect probe to any periodic signal and set trigger level to the middle of the signal. Now move trigger level above or below your signal and use horisontal position knob. Signal is cutted. Just like in the first post that i wrote in this thread.

Maybe I didn't explain it preciseley. I know that the exaple that i wrote above is not what you normally do with your oscilloscope, but it shows the problem...
Imagine that you have some periodic signal, single pulse or frame and it appears every 1 minute period.
When it appears, oscilloscope triggers it, and then 1 minute without trigger.
If you now try to move signal horizontally you will see that only 4k data of the signal is displayed, even if i have mem. depth set to >4k.

xyz

Hi, Any news about the update?