SDS800X HD - Issue disscusions - is it me, or the scope?

[electronics hobbyist]

I have another issue:
I set up a qualified trigger, but the edge trigger is not stable.
The deviation gets worse, if i set the trigger level lower.

Can you explain your input signal? If you adjust the C4 vertical gear down, will there be a problem? I did not reproduce this problem; You can attach setup.xml. If the configuration is the same, it should be related to the input signal.

[eTobey]

I tried edge trigger to test, and went back to qualified trigger. Now the problem dissappeared, and i have not saved a setup file  .

Tought it was a lack of knowledge, but seemingly it wasnt...

Edit:
found the culprit:
When "alternating edge" is selected on any channel on trigger type edge, then the qualified trigger has this issue.

see setupfile attached.

[gitm]

Has anyone else turned on their SDS800X to find a fixed DC offset (~700 mV) on CH1 and CH1 only?

This has happened twice to mine immediately at power-on on two different days.  CH2, CH3, and CH4 all had no offset (i.e. 0) as expected.  Nothing was connected to any of the inputs.  Selecting the vertical position rotor and pushing to return CH1 trace to 0 had no effect and in the CH1 “box” (bottom left of screen) showed, IIRC, 0 mV.  Scrolling the position down to place the trace on 0 would then show a negative offset.  Setting the vertical position explicitly in the CH1 position entry box to 0 would position the trace to 0+~700mV. 

Shutdown, disconnect power, reboot, and set to default had no effect (something bad stored?). In each case to get the scope back to powering on with DC offset of 0, I set the scope to default and then ran selfcal after warming up for 30 minutes.  Once the selfcal completed the offset was now at 0.   I rebooted the scope and the offset was still gone.  Rebooting a few more times and the offset did not reappear.  So I continued my actual testing for the day.

After a couple of days not being used, I turned on the scope yesterday and the offset returned for a second time.  Same investigation and results as the above paragraph.  I then again continued my actual testing for the day.

I turned the SDS800X on today and the offset remains at 0.   

I will say that “testing for the day” was looking at a 5V/12V rail-splitter with DC coupling and using the vertical position offsets at -2.5V and -6.0V to see what ripple, noise, and droop were present under differing loads, 10X attenuation and 10mV/, and running FFTs.  Maybe this is related.  But then it didn’t reappear this morning. 

Anyone else seen this?

[eTobey]

Pictures! You have to take pictures, because some will never believe you. And you may consider, that some aspects of it a very confusing, so you take your time and try to figure out if its a problem with the setup.

[Martin72]

Has anyone else turned on their SDS800X to find a fixed DC offset (~700 mV) on CH1 and CH1 only?

I didn't have it with my 800X HD, but I had something similar with my 2000X HD at the time.
There, too, the spook disappeared after one or two self-calibrations.

[gitm]

Pictures! You have to take pictures, because some will never believe you. And you may consider, that some aspects of it a very confusing, so you take your time and try to figure out if its a problem with the setup.

Thanks for the response.  But it is irrelevant whether “some believe me” or not.  The question was "whether anyone else has observed this same phenomenon?”  If others have, then they will reply stating such and, implicitly, believe me, not that it matters.  Others that have not, may not reply or might nit pick because “the internet”.  I’m a big boy and my delicate psyche might not break after all.

Regarding “taking my time”, I spent the better part of two days “figuring out if its a problem with the setup” — it’s not.  My first reactions were, "okay what’s happening here?” and “what did I do wrong?”

Regarding “pictures”, I’m fairly certain that a static picture of a trace with an offset of ~700 mV and a CH1 box saying “0.00V” doesn’t help with explaining the issue (or my incompetence) more so than my words?  It’s pretty straight forward and nothing I’ve experienced with my 4 other scopes.

I appreciate the reply/advice and I am not in any way being sarcastic — really, honestly, and truly.

[electronics hobbyist]

Anyone else seen this?

Believe you have encountered this problem. So far, I haven't seen this phenomenon in SDS800XHD. If it appears next time, you can save the setup and let's see if we can duplicate it.

[tautech]

Has anyone else turned on their SDS800X to find a fixed DC offset (~700 mV) on CH1 and CH1 only?

Anyone else seen this?

Not.
There is mention of offset issues in beta FW release notes but not this exact issue it seems.

It is customary when reporting an issue to state the FW version in use.

[gitm]

Not.
There is mention of offset issues in beta FW release notes but not this exact issue it seems.

It is customary when reporting an issue to state the FW version in use.

Point taken.

Software Version 1.1.3.1
UBOOT-OS Version 2.8.10
FPGA Version 2023-12-29
HW Version 00

[tautech]

Not.
There is mention of offset issues in beta FW release notes but not this exact issue it seems.

It is customary when reporting an issue to state the FW version in use.

Point taken.

Software Version 1.1.3.1
UBOOT-OS Version 2.8.10
FPGA Version 2023-12-29
HW Version 00

https://int.siglent.com/upload_file/zip/firmware/Oscilloscope/SDS800X_HD_V1.1.3.3_EN.zip

[gitm]

Thank you.  While the release notes don’t mention offset issues, it does mention "Solve the problem that Bode Plot cannot control sdg1000”.  I do have a SDG1062X, so I’m up for a firmware update. 

[tautech]

Thank you.  While the release notes don’t mention offset issues, it does mention "Solve the problem that Bode Plot cannot control sdg1000”.  I do have a SDG1062X, so I’m up for a firmware update. 

No problem.
I think you will find this means the earlier SDG1k series, not your later 1kX model.

In Bode plot mode all Siglent AWGs are intended to be supported for the FRA stimulus, regardless of their vintage.

[eTobey]

Contradictory findings:
Either the manual is wrong or the scope shows wrong values. I can only count like a few dozent of points.

The timebase also does not show all the time 50Mpts if you zoom out  its sometimes 20 or 40 Mpts.

[eTobey]

Another thing in the manual that does not add up:
Again... 

The X2 is whereever you set it up. So it can also be on the left side. The same problem is with the Y1/2.

[ebastler]

Another thing in the manual that does not add up:
Again... 

The X2 is whereever you set it up. So it can also be on the left side. The same problem is with the Y1/2.

I take "left (default)" to mean that by default -- i.e. before you set it up differently -- X1 is on the left. Makes sense to me?

[ebastler]

Contradictory findings:
Either the manual is wrong or the scope shows wrong values. I can only count like a few dozent of points.

The timebase also does not show all the time 50Mpts if you zoom out  its sometimes 20 or 40 Mpts.

Should be exactly 20 points, right? 200 ns total sweep time, 100 MSa/s, so 20 Samples in 200 ns. You can see the individual data points when you switch the display mode to "Dot".

Did you acquire that data with a much slower time base, then stop and zoom in? In that case, the number of number of samples indicated in the info box might be the number of samples acquired in the sweep, rather than the number of samples shown on-screen at the moment? (I don't have access to my scope at the moment.) The manual would be incorrect in that case.

If the above hypothesis is right, I would probably prefer the scope to behave like stated in the manual, i.e. always tell me how many data points are behind the trace I see on-screen at the moment. In which case this would be a bug or improvement request.

[2N3055]

Another thing in the manual that does not add up:
Again... 

The X2 is whereever you set it up. So it can also be on the left side. The same problem is with the Y1/2.

I take "left (default)" to mean that by default -- i.e. before you set it up differently -- X1 is on the left. Makes sense to me?

It means left as being first on the time axis when doing subtraction.  Diff will be X1-X2.
If you set  X1 left and x2 right, diff will be 10 ns. If you set them the other way around then it will be -10ns.
X1-X2

[2N3055]

Contradictory findings:
Either the manual is wrong or the scope shows wrong values. I can only count like a few dozent of points.

The timebase also does not show all the time 50Mpts if you zoom out  its sometimes 20 or 40 Mpts.

Should be exactly 20 points, right? 200 ns total sweep time, 100 MSa/s, so 20 Samples in 200 ns. You can see the individual data points when you switch the display mode to "Dot".

Did you acquire that data with a much slower time base, then stop and zoom in? In that case, the number of number of samples indicated in the info box might be the number of samples acquired in the sweep, rather than the number of samples shown on-screen at the moment? (I don't have access to my scope at the moment.) The manual would be incorrect in that case.

If the above hypothesis is right, I would probably prefer the scope to behave like stated in the manual, i.e. always tell me how many data points are behind the trace I see on-screen at the moment. In which case this would be a bug or improvement request.

What you saying is not improvement or bug.
Scope shows sampled, acquired points, not current screen points.
What is purpose of useless metric of current screen?

And for other thing eTobey mentions:

In acquisition you set up Max point scope will capture but scope automatically sets points based on timebase.
And for instance, with 2 ch on as you go through timebases once you reach 50Mpts, it will start alternating between 40 and 50 MPts.

I'm guessing you know why but he doesn't understand that if you multiply time on screen with sampling rate you get what sample numbers are possible....

Best,

[tautech]

Contradictory findings:
Either the manual is wrong or the scope shows wrong values. I can only count like a few dozent of points.

The timebase also does not show all the time 50Mpts if you zoom out  its sometimes 20 or 40 Mpts.

The answer is staring you in the face...Peak Detect which is an entirely different acquisition mode and why this mode is always displayed when you select it.

Wanna see sample points, select Normal and Dot mode.

[eTobey]

It means left as being first on the time axis when doing subtraction.  Diff will be X1-X2.
If you set  X1 left and x2 right, diff will be 10 ns. If you set them the other way around then it will be 10ns.
X1-X2

You are dead wrong! It gives -10ns. Even more, when X1 is sometimes on the left, and sometimes on the right, there is a huge risk of confusion, which really bothers me, as electronics can be confusing enough already.

This is not meant to be rude: but i really get frustrated of people saying things that are wrong with an quite a high assurance (in general). Arent we all interested in having a good product?

[2N3055]

It means left as being first on the time axis when doing subtraction.  Diff will be X1-X2.
If you set  X1 left and x2 right, diff will be 10 ns. If you set them the other way around then it will be -10ns.
X1-X2

You are dead wrong! It gives -10ns. Even more, when X1 is sometimes on the left, and sometimes on the right, there is a huge risk of confusion, which really bothers me, as electronics can be confusing enough already.

This is not meant to be rude: but i really get frustrated of people saying things that are wrong with an quite a high assurance (in general). Arent we all interested in having a good product?

Off course it is meant to be rude...  The hint is in a tone and actual rude words you use...
Read occasionally your own signature...

Hint it was a typo... I wasn't wearing glases and didn't notice there is no minus sign.. Fixed now.

[eTobey]

And for instance, with 2 ch on as you go through timebases once you reach 50Mpts, it will start alternating between 40 and 50 MPts.

I'm guessing you know why but he doesn't understand that if you multiply time on screen with sampling rate you get what sample numbers are possible....

You are wrong:
at 20ms/div i got 20Mpts, but above and below i get 50Mpts... (see attached setup)

Are talking about me not understanding? I might miss some things, as i have a few projects ongoing, but if one is able to explain it, i will quickly grasp it.

[eTobey]

Off course it is meant to be rude...  The hint is in a tone and actual rude words you use...
Read occasionally your own signature...

Hint it was a typo... I wasn't wearing glases and didn't notice there is no minus sign.. Fixed now.

You may have gotten that tone wrong. But what is the actual "rude" word? I just expressed my feelings, and just why its is so.

If you have made a typo, it should be clear, that this sentence does not apply anymore, and there is no need of further discussion...

[2N3055]

And for instance, with 2 ch on as you go through timebases once you reach 50Mpts, it will start alternating between 40 and 50 MPts.

I'm guessing you know why but he doesn't understand that if you multiply time on screen with sampling rate you get what sample numbers are possible....

I can proove you wrong again:
at 20ms/div i got 20Mpts, but above and below i get 50Mpts... (see attached setup)

Are talking about me not understanding? I might miss some things, as i have a few projects ongoing, but if one is able to explain it, i will quickly grasp it.

We said and said repeatedly:  nobody is going to solve your puzzles.
Explain yourself better or you get what you get.
You could have explained that at 20ms/in particular you get this shorter length.
At 20ms/div it seems that scope organizes data as if all 4 channels are on even when they are not.
It might be necessary because of how internal data pump works at that sample rate or maybe it can be optimized.
Will ask.

But you still need to work on your communication....

[2N3055]

Off course it is meant to be rude...  The hint is in a tone and actual rude words you use...
Read occasionally your own signature...

Hint it was a typo... I wasn't wearing glases and didn't notice there is no minus sign.. Fixed now.

You may have gotten that tone wrong. But what is the actual "rude" word? I just expressed my feelings, and just why its is so.

If you have made a typo, it should be clear, that this sentence does not apply anymore, and there is no need of further discussion...

Let me try to explain, and now I ask you to not get offended.

To me it seems you can't hardly wait to see something that can used to argue to start arguing.

If someone corrects you and then writes same as you it is either a mistake or the other side didn't take their meds.
Both are good reason not to react with "AHAAAAA I have you now!!!!!!".

That kind of reaction is not truth seeking but an effort to embarrass somebody.

This is not a competition.
If in doubt, clarify...