Rigol DHO800/900 Oscilloscope Bug Reports + Firmware

[dreamcat4]

because when you do buy some lets say 'more sophisticated' dedicaded external standalone l.a., then they can do at least some types of voltage range adjustment. if not threshold always, but maybe some fewer ones. or that the threshold hysteresis becomes linked relative to the total voltage swing. or different threshold setting for the 1.8, 3v3 and so on. in fact this matter reminds me of some higher quality programmers. that is also multi voltage for different types of chips

[TurboTom]

Decoding a digital signal with a fixed timing shouldn't require a hysteresis as long as the two signal levels are far enough apart from the threshold. Any noise and erroneous signal changes should be (temporally) far away from the interval when the level is to be checked for evaluation / decoding. Of course, the fact that a good decoding algorithm still incorporates some hysteresis, stays undisputed.

[2N3055]

so if that is it, then any such threshold is not in hardware but instead rather like an adjustable software debounce? is that really correct behaviour? because i suppose it can be ok when the input is from an analog channels here. that can be done in scope software without such debounce. yet if the input channels are digital inputs from the la. then this is not the case.

It is not even debouncing  per se .. Decode is software that runs on sampled analog data buffer. Or on digital data buffer. Difference being that on analog data signal is digitized based on threshold as a first pass, than fed into state machine to decode protocol. On digital data buffer, that one gets directly fed to decode step.

because when you do buy some lets say 'more sophisticated' dedicaded external standalone l.a., then they can do at least some types of voltage range adjustment. if not threshold always, but maybe some fewer ones. or that the threshold hysteresis becomes linked relative to the total voltage swing. or different threshold setting for the 1.8, 3v3 and so on. in fact this matter reminds me of some higher quality programmers. that is also multi voltage for different types of chips

There is certain hysteresis just fixed one.  Few percent at most. That works quite well if captured data has well defined edges. Noise on top won't matter much.   Mostly, on scopes I have here (Keysight, Micsig, Siglent) if you have so much noise on data that scopes have problem decoding, you also have problem with hardware having false edge transitions... Pretty much situation where you try to fix hardware to have cleaner signal...

On Rigol DHO nobody knows how well it works. There are just few out in the wild and those are not tested systematically (yet)...


Picoscope has adjustable threshold level and hysteresis on all protocols..

[ddv2005]

eg. Does it stop decoding you move it above the top of the signal or make it negative on the working signal.
Edit: Can you drag the threshold voltage up and down with your finger on these? Micsigs can... 

I ran several test with the threshold voltage and found that it is the threshold voltage scale issue. If I set the probe to X1 scale then everything works fine but with the X10 probe scale does not work because  the actual threshold voltage 10 times less than I set. But if I increase the threshold voltage 10 times (10V instead of 1V) then decoding starts again.

[Martin72]

That sounds familiar to me..

[EEVblog]

The easy way to reproduce the bug. Rigol DHO804 DHO800 oscilloscope waveform disappear in stop mode:

Press Default, set roll mode OFF, change trigger level to some reasonable level, 500 ms/div, 200 mV/div, do SINGLE waveform capture.
When capture is done, change horizontal to 1 s/div, enable Vernier (press horizontal nob), change horizontal to 1.2, 1.3 s/div.

Confirmed:

[Serg65536]

Rigol DHO800 vertical zoom bias limit while stopped. Bug, issue.
It's impossible to look at 12bit details on signals captured outside bias range of lower scales. Even in zoom mode.
https://youtu.be/ANvczYUG8iU

[2N3055]

In second video, with 25Mpts it seems unresponsive and slow. That needs to be tested to see if there is some problem there.
That looks much worse than DS1000Z. DS1000Z was not fast with vertical adjustments but handled 24 Mpts buffer just fine.
How is it behaving with long memory in general?

[Serg65536]

Rigol DHO800 "vertical truncation is not updated while moving vertically" bug issue
Stop the acquisition, move waveform outside the screen, change horizontal position, or horizontal scale, or vertical scale. Move waveform back and it is truncated until you change horizontal position, or horizontal scale, or vertical scale again.
Firmware version 1.00
https://youtu.be/ZpYqQNpFG1g

[Martin72]

Boah, this is weird..

[Fungus]

Boah, this is weird..

It's not weird at all. The waveform normally stops updating when you're moving it vertically so they must just be moving a bitmap around during vertical moves, they're not regenerating it.

If that bitmap is generated when the waveform is offscreen then there's nothing to see when you move it into view.

Move waveform back and it is truncated until you change horizontal position, or horizontal scale, or vertical scale again.

ie. Until you cause a refresh/re-decimation of the signal on screen.

It's really just an annoyance. Nothing is lost and you can easily make the missing part reappear when you know how.

(touch the screen and wiggle it a bit or jiggle your mouse wheel)

[Serg65536]

No way to change any specific XY mode options: all are inactive (the user manual confirms this).
Rigol DHO800 "Bad apple" oscilloscope music file
Frame rate is not sufficient, the picture is not clear, some objects are blurred. Firmware 1.00.
Please, leave a comment if you know how to improve the picture.
https://youtu.be/R88DA15Iv8A

[Cees]

About the AWG function of the DHO924S

Generator connected directly to inputs 1 and 2

• Set the frequency range to a range of 100 Hz and 200kHz and the resolution is 10 points per decade. If I'm lucky the plot will start. As a result of the coupling I will see a flat response as well as the phase remaining at zero degrees.
• Then I set the response to 10 Hz and 200kHz and all settings remain unchanged. The result of this change is that the plot will not be started.
• I can repeat this test many times and sometimes both settings may or may not work. I am surprised that in this specific case no external device is connected, so I expect that this should always work.

What else strikes me:

• I have tried to adjust the input sensitivity manually but this has no effect. So it seems that there is a kind of auto ranging.
• In the case of auto ranging, I see in the upper part of the plot that the amplitude of both input channels is sometimes empty or that the signals are much too large and therefore it seems as if the auto ranging is not   functioning properly.
• If I am lucky enough to have a plot appear it is not possible to adjust the vertical scale (it is always at -60dB to +60 dB). The same applies to the phase, which cannot be adjusted in the case of a small deviation.
• Based on the fixed vertical scales, it is desirable that both phase and amplitude can be adjusted, possibly supplemented with “auto ranging”.

In summary, I now have a device that I purchased explicitly for the bode plot function and which does not appear to work, both directly connected to the inputs of the oscilloscope, but the problems seem to be even worse when measuring an external device such as a simple analogue class. A amplifier for audio with only 10 dB gain.


As long as I take measurements starting at 1 kHz and set the Y axis of both input channels in his most  insensitive  setting beforehand then the device is able to set the gain correctly afterwards.

[Serg65536]

If that bitmap is generated when the waveform is offscreen then there's nothing to see when you move it into view.
It's really just an annoyance. Nothing is lost and you can easily make the missing part reappear when you know how.

It's a bug in a classical meaning of the term. You are moving the waveform, not the bitmap. The bitmap should be updated automatically.

[Martin72]

It's not weird at all.

Siglent SDS1104X-E:



No problem, regardless of the memdepth, acq. mode, etc..

[TimFox]

I started a thread about the Bode Plot function on the DHO914S: 
https://www.eevblog.com/forum/testgear/rigol-dho914s-bode-plot/

[Mechatrommer]

today i tried saving wave data in bin, csv and wfm format, both from screen and memory into usb drive (D:). tried 1 and 2 channel active.. after saving wfm, 1Mpts memory.. dso channel traces halted or disappear, i need to restart the dso to get back the signal. can anyone reproduce?

[TurboTom]

Edit: Bug removed in Firmware 00.01.01.00.02

DHO914S, F/W 00.01.00

The scope app reliably crashes when enabling the AWG, changing the frequency to >3 kHz via the touch screen / decimal pad and then trying to change the AWG frequency via encoder 1. Restart is most of the times possible within a few seconds, but sometimes it takes longer than a cold start... This scope's Firmware is Alpha stadium 


Edit: I checked the problem a little more in-detail: It seems, regardless of how it is approached, of the waveform and other settings, everytime when the AWG frequency threshold 2.147kHz -> 2.148kHz is crossed using encoder 1, the scope app crashes. In the aftermath, one may be greeted with "Open App Again" which is rather fast or "Close App" which takes much longer (may vary), almost like a cold start.
Reducing the frequency via encoder 1 from 2.148kHz works, but from above that frequency, the app also crashes. Strange thing...

[Martin72]

@Mechatrommer:

No problems here, csv and wfm, from memory...

[Martin72]

Rigol DHO800 "vertical truncation is not updated while moving vertically" bug issue
Stop the acquisition, move waveform outside the screen, change horizontal position, or horizontal scale, or vertical scale. Move waveform back and it is truncated until you change horizontal position, or horizontal scale, or vertical scale again.

Can confirm this (tried vertical), more:
I had the first crash of the day with it....

[ebastler]

@Mechatrommer:
No problems here, csv and wfm, from memory...

@Mechatrommer:
Did you try a different USB stick? Maybe the DHO took offense with its format, size, volume name, some other file name present in the directory, or the like?

[iMo]

,,This scope's Firmware is Alpha stadium 

That is the Agile Development Live..
The only annoyance in this case - the Sprint will be 1 year long 

[Mechatrommer]

@Mechatrommer:
No problems here, csv and wfm, from memory...

@Mechatrommer:
Did you try a different USB stick? Maybe the DHO took offense with its format, size, volume name, some other file name present in the directory, or the like?

thanks for clarification. i formatted the stick FAT32.. i'll try again with different stick next time. earlier the wfm files did (looks like) save correctly to the stick, but the signal halted after that and UI became slowish. i'll try again.

[EEVblog]

Rigol DHO800 "vertical truncation is not updated while moving vertically" bug issue
Stop the acquisition, move waveform outside the screen, change horizontal position, or horizontal scale, or vertical scale. Move waveform back and it is truncated until you change horizontal position, or horizontal scale, or vertical scale again.

Can confirm this (tried vertical), more:
I had the first crash of the day with it....

Is that the same one I showed in my review video?

[Martin72]

I'll have to look at it again in a few days.
But it was something like this:
Stopped, turned the vertical down until the signal was no longer visible.
Then changed the vertical setting once, then turned the line up again.
And it was then actually only a line, no signal more, "Run/Stop" again pressed, signal was visible, but it was then no matter whether you had changed vertically or horizontally.
The signal remained the same until I switched off the scope and switched it on again.