Rigol DHO800/900 Oscilloscope Bug Reports + Firmware

[Mechatrommer]

After a restart, it would apparently want to load that last used state (maybe waited for a trigger to happen to fill in that buffer?), and that took ages. But eventually it booted.

that means, last setting is stored somewhere not in sd card. but where? we need to find a way to zero those memory..

In the SRAM chip. I assme they don't want to wear the flash out by writing to it after every single twist of a knob.

what are you smoking again my friend? SRAM is volatile... https://en.wikipedia.org/wiki/Static_random-access_memory they can do it in Flash and save setting at every "Power Off" button, not every knob twist. not everybody can do 100K times power on and off, which is the write endurance of Flash.

[shapirus]

save setting at every "Power Off" button, not every knob twist.

It's neither. I have tested the following scenarios:

1) change vertical scale, immediately pull the power cord
2) change vertical scale, immediately press the (soft) power button twice
3) change vertical scale, wait a couple of minutes, press the power button twice

Only in scenario 3 the change was saved. This is an indication that a buffer + interval save algorithm may be used.

[Mechatrommer]

so the programmer is not as clever as i thought.

[ebastler]

It's neither. I have tested the following scenarios:

1) change vertical scale, immediately pull the power cord
2) change vertical scale, immediately press the (soft) power button twice
3) change vertical scale, wait a couple of minutes, press the power button twice

Only in scenario 3 the change was saved. This is an indication that a buffer + interval save algorithm may be used.

So how about scenario 4: change scale, wait a couple of minutes, then pull the power cord?
If it still remembers the settings change, then saving them is purely timeout-based.

[shapirus]

So how about scenario 4: change scale, wait a couple of minutes, then pull the power cord?
If it still remembers the settings change, then saving them is purely timeout-based.

Yes that's exactly what happens. It does not need the power button to be pressed for the settings to get saved, but it appears to need some time to pass after a change is made.

[Fungus]

So how about scenario 4: change scale, wait a couple of minutes, then pull the power cord?
If it still remembers the settings change, then saving them is purely timeout-based.

Yes that's exactly what happens. It does not need the power button to be pressed for the settings to get saved, but it appears to need some time to pass after a change is made.

It's a very short time, certainly much less than "a couple of minutes".

I'd also be very surprised if the settings aren't checksummed against corruption.

[shapirus]

It's a very short time, certainly much less than "a couple of minutes".

I would assume 5-10 seconds, that would be a sensible setting. I couldn't care less to go for determining it experimentally, though, given the painfully long boot time. Could be tested by restarting just the app, though, by killing its process from the shell (and then it'll restart automatically). That's an idea for someone who wants to volunteer to test it.

I'd also be very surprised if the settings aren't checksummed against corruption.

Haha lol.
(no I have no other comment on this one.)

[sequoia_hope]

Hello everyone. I received my DHO804 today. Its a relatively nice scope, but I immediately discovered some issues with SPI decoding. I searched this thread and I see that DHO900 users are having SPI decoding issues with the logic analyzer, but in my case I am having an issue with the analog SPI decoding.

I am reading a 24 bit SPI value, and the waveform is absolutely rock solid. As far as I know, I have all the right settings, and having tried flipping a few SPI settings nothing else was any better.

What I am observing is that, using the SPi trigger mode, the Hex value overlaid on the SPI waveform is inconsistent even with a very solid displayed waveform. I turned on display persistence and I see no jitter at all in the waveform, but the displayed hex value changes at random. The obvious thing to check is that the SPI is triggered on the correct edge, but looking at my data it is clear I have the correct setting for that.

What is worse is that the inconsistent hex reading is highly dependent on the "Mem Depth" setting. With 100khz SPI, I have to set it to 10k Mem Depth to get even close to consistent hex values. If I change it to any other setting, the interpreted hex values are all over the place, changing every sample.

I'm really hoping I just have a setting wrong. This is my first new scope purchase in 13 years and I was so eager to move on from my buggy old scope, I had hoped I wasn't buying a buggy new scope! (I already found a second bug, but one thing at at time.)

Please see attached screenshots. Cheers.

EDIT: I also just noticed that with faster SPI, in this case 1Mhz clock, it seems to be more stable. At 1MHz SPI and 1k or 10k Mem Depth, the hex reading is very stable, but that reading still changes constantly at 100k or 1M Mem Depth. With more experimentation I see that it is able to display multiple samples at once in a Decode Window, and that the timecale combined with the Mem Depth make all the difference. For a fully zoomed in value, where one sample takes up the entire width of the screen, a lower Mem Depth seems better. If you decrease the timescale so that multiple SPI transactions are on screen at once, you need to increase the Mem Depth. This makes some sense, but the scope give any indication as to what might be wrong if you have the setting wrong. And what makes no sense to me is that higher Mem Depth values can result in bad data decoding. Anyway I am glad I found that some fiddling can lead to more consistent behavior, but it seems like a real bug that high Mem Depth values can lead to SPI decoding errors, and that no warnings or messages are displayed to alert the user to a bad setting combo.

[Aleksandr]

And try additionally enabling the input signal bandwidth limitation of 20 MHz for each channel.

[lunix]

Hi Sequioa: I note that you are triggering on SPI data, using different thresholds for CLK, CS, MISO, and the trigger condition you've chosen is "don't care".  Also pay attention to CS polarity and data sample clock edge. I would not be surprised by changing data since you have not set any particular bits as significant for triggering.

[ebastler]

What I am observing is that, using the SPi trigger mode, the Hex value overlaid on the SPI waveform is inconsistent even with a very solid displayed waveform. [...]
The obvious thing to check is that the SPI is triggered on the correct edge, but looking at my data it is clear I have the correct setting for that.

I no longer have my DHO1000, but I seem to recall that there are separate settings for the clock polarity in the Trigger and in the Decoder settings, respectively. You have only shown us your Trigger settings in the screenshot. Might it be the case that in the Decoder settings you have told the scope to sample at the rising clock edge, i.e. just when the data line changes?

[Howardlong]

I keep returning to this thread with an increasingly forlorn hope that there'll be a spectacular firmware rabbit pulled out of a hat at some point, making my DHO924S more than a desk ornament one day.

Should I consider this scope a write-off?

[Mechatrommer]

I keep returning to this thread with an increasingly forlorn hope that there'll be a spectacular firmware rabbit pulled out of a hat at some point, making my DHO924S more than a desk ornament one day.
Should I consider this scope a write-off?

have you purchased siglent sds800x-hd and LA module? since iirc your job is mainly LA, so i hope you can make comparison how far off dho900 compared to sds800x+LA. and i think your life need to move on rather continuously depending on crippled dho900 as i understand your situation from previous descriptions. but for us who dont really depend our life on LA (serial nor parallel) serious work, we hope there will be FW fix in the future. so we will put our dho800 in box for a while since person like me still have DS1054Z to work with. and since they are so much affordable now like smartphones, if i'm going crazy, i'll get one sds800x-hd to try, or even to use it as main bench scope if its really that good, ymmv. (the problem with sds804x or sds824x is they keep disappearing (out of stock) from aliexpress when i want to look for them)

[PELL]

I keep returning to this thread with an increasingly forlorn hope that there'll be a spectacular firmware rabbit pulled out of a hat at some point, making my DHO924S more than a desk ornament one day.

me too, it's very disappointing that Rigol has not published a DHO software update for almost half a year now

I have some direct contact with their support. every time I asked "when" they simply replied "It's not scheduled but we are working on it" (and I just asked once again yesterday). by contrast, their competitor is updating firmware very frequently

I do hear from some sources they are facing some human resource problems right now due to various reasons, mainly poor management.

Anyway, I will still keep my DHO because it is not that bad for my use case. I do hope they can release new software asap.

[Howardlong]

I keep returning to this thread with an increasingly forlorn hope that there'll be a spectacular firmware rabbit pulled out of a hat at some point, making my DHO924S more than a desk ornament one day.
Should I consider this scope a write-off?

have you purchased siglent sds800x-hd and LA module? since iirc your job is mainly LA, so i hope you can make comparison how far off dho900 compared to sds800x+LA. and i think your life need to move on rather continuously depending on crippled dho900 as i understand your situation from previous descriptions. but for us who dont really depend our life on LA (serial nor parallel) serious work, we hope there will be FW fix in the future. so we will put our dho800 in box for a while since person like me still have DS1054Z to work with. and since they are so much affordable now like smartphones, if i'm going crazy, i'll get one sds800x-hd to try, or even to use it as main bench scope if its really that good, ymmv. (the problem with sds804x or sds824x is they keep disappearing (out of stock) from aliexpress when i want to look for them)

So I do already have an SDS1204X-E with the external SLA1016 LA pod, and I find the LA implementation to be a horrible implementation with plenty of functional and non-functional limitations. As far as I can tell, the SDS800X-HD has a very similar form factor to the SDS1204X-E, and uses the same LA pod.

It was the diminutive form factor of the Rigol DHO924S that I was interested in.

Here's a comment I made on the combo a few years ago about the SDS1204X-E and SLA1016 pod:
https://www.eevblog.com/forum/testgear/siglent-sds1204x-e-released-for-domestic-markets-in-china/msg3259848/#msg3259848

Although this scope isn't bad, I have a couple of comments about the optional LA and AFG.

If you're thinking of adding the LA to make it an MSO, I find the LA on this scope to be very weak indeed. For an MSO at this level, I consider the older Rigol DS1000Z+ with LA probes to be a significantly better solution. On the 1104X-E, the UI performance grinds to a halt with the LA attached and it's a substantial extra package to carry about that can't help but take up bench space.

Similarly, the external AFG on the Siglent also is nowhere near as neat as the Rigol's internal dual channel unit, but you have to buy the Rigol's at the time of scope purchase.

So if you're only looking for a 4 channel scope only, the Siglent is definitely a better than the Rigol DS1000Z series. Just that I find the LA and AFG on the Siglent are rather disappointing.

To be fair I have more scopes than I can shake a stick at, it's not like I really need another one. However for field use, had the DHO924S worked out as anticipated and advertised, it would have found its way on trips. In recent times I've found myself making do with the Analog and Digital Discoveries for field work more and more, with a scope becoming more of an exception. Carrying a portable monitor with me helps in that regard so there's enough screen real estate. The AD lacks in memory depth, with the DD filling in in that regard. I'd still prefer a compact fully integrated standalone MSO though for my field work nirvana.

[tautech]

So I do already have an SDS1204X-E with the external SLA1016 LA pod, and I find the LA implementation to be a horrible implementation with plenty of functional and non-functional limitations. As far as I can tell, the SDS800X-HD has a very similar form factor to the SDS1204X-E, and uses the same LA pod.

100% and exactly where the similarities end.


SLA1016 must be SW upgraded to work with SDS800/1000X HD models.
X-E implementation is now changed for the new models with a much better UI and touch and mouse control provides for a superior user experience.

[Mechatrommer]

So I do already have an SDS1204X-E with the external SLA1016 LA pod, and I find the LA implementation to be a horrible implementation with plenty of functional and non-functional limitations. As far as I can tell, the SDS800X-HD has a very similar form factor to the SDS1204X-E, and uses the same LA pod.

100% and exactly where the similarities end....
[img]...

i wish parallel LA (in dho800/900) can show hex or dec value at each digital transition so i dont have to decode myself. much like serial LA decoding function/UI... your screenshot of siglent scope also show lack of parallel LA decoding, or is it turned OFF?

[tautech]

So I do already have an SDS1204X-E with the external SLA1016 LA pod, and I find the LA implementation to be a horrible implementation with plenty of functional and non-functional limitations. As far as I can tell, the SDS800X-HD has a very similar form factor to the SDS1204X-E, and uses the same LA pod.

100% and exactly where the similarities end....
[img]...

i wish parallel LA (in dho800/900) can show hex or dec value at each digital transition so i dont have to decode myself. much like serial LA decoding function/UI... your screenshot of siglent scope also show lack of parallel LA decoding, or is it turned OFF?

Nothing connected, just an image of the UI.

Mech, we are about to attend a 3 day exhibition (see sig) and we will have many instruments with live displays so sometime this coming week I will capture something to show you.

[eTobey]

I wonder how the Rigol would compare to the siglent with the following measurement:

- A squarewave at 10Hz, with a level from 0 - 6.6V (maybe interleaved with a 3.3V level) and 50% duty.
- Zoomed in to 0V at a scale of 20mV.
- Avaraging function activated

See the picture attached.

[ebastler]

I wonder how the Rigol would compare to the siglent with the following measurement:
- A squarewave at 10Hz, with a level from 0 - 6.6V (maybe interleaved with a 3.3V level) and 50% duty.
- Zoomed in to 0V at a scale of 20mV.

It would not compare at all, because the Rigol cannot do vertical zoom. Count your blessings! 

Well, one can stop the acquisition and crank up the vertical amplification after the fact to see the settling behaviour. If you want others to try and test on their scopes, you should also specify how the signal was coupled into the scope. Using the stock probes? BNC cable with 50 Ohm termination at the scope? If so, what terminator did you use -- was it a decent one?

[csuhi17]

I wonder how the Rigol would compare to the siglent with the following measurement:

Like most scopes that do not have a vertical zoom function.

If you saved the wave to Ref, it is possible to check the bottom and top, but I did not look into how many points you lose with it.

It can't in Run mode.

[Mechatrommer]

I wonder how the Rigol would compare to the siglent with the following measurement:
- A squarewave at 10Hz, with a level from 0 - 6.6V (maybe interleaved with a 3.3V level) and 50% duty.
- Zoomed in to 0V at a scale of 20mV.

It would not compare at all, because the Rigol cannot do vertical zoom. Count your blessings! 

whats the point of it? trying to zoom in to 1% overshoot is marketing ploy... 5% and more? is readily available to see without zoom in to tell whether your circuit need rectification or within acceptable range..

[TurboTom]

Without knowing the probing method, replicating the test won't produce significant results. Nenvertheless, out of curiosity, I attempted a similar "shot" on my DHO1000, yet (obviously) in stopped mode. F/W is 02.12, as a generator I used an SDG6000X, "Radar" ARB waveform since this contains several square pulses of varying amplitude. I could only select 5Vp since I connected the generator via a short RG316 cable and in-line BNC terminator, hence the available amplitude got halved. Except for some very fast overshoot, there was no deformation of the trace observable (as expected). I'ld be surprised if the DHO800 or the SDS800X HD would perform any different under the same conditions.

[Fungus]

I wonder how the Rigol would compare to the siglent with the following measurement:

- A squarewave at 10Hz, with a level from 0 - 6.6V (maybe interleaved with a 3.3V level) and 50% duty.
- Zoomed in to 0V at a scale of 20mV.
- Avaraging function activated

See the picture attached.

a) Is that actually useful?
b) You can use a math channel if you really want to see that. Put in any offset/scale that you want.

Sure, (b) isn't as "cool", but see point (a).

The math channel here is showing a range of 6mV at the top corner of a 300mV square wave.

[eTobey]

I should have postet the link, how it looks on my side. (https://www.eevblog.com/forum/beginners/probe-compensated-but-level-of-square-signal-gt-20ms-not-looking-good/)

I did not add my connection details, because i would have accepted anything that you would have been shown. Except, that the scales were not really comparable in one occasion.

I do want to measure currents, that would rapidly increase, and also very prescisely. All that in conjunction with the programming of my controller, so i could detect any issues, or see its precision. Not really possible it seems with the Siglent. 

Interestingly, my cheap and tiny scopes do better here.