OWON VDS1022I Quick Teardown (versus the Hantek 6022be)

[Gyro]

Good work on correcting the Russian tips and translations. 

I also suggest Gyro send florentbr a set of their beautiful icons and suggest to include them in the new release?

Thanks for the compliment , but I'm not actually sure that my icons would add much now. Florent already seems to have cherry-picked the ones that he found useful but clearly had his own ideas on others. These seem quite understandable (for instance he used a 7 segment digital display rather than my analogue meter dial for 'measurements'). His Math one is better too. He has also changed the menu structure, which makes some of the others redundant anyway.

Florent's choices might possibly be criticised for being less colourful (well, monochrome) compared to mine, but again this resolves some problems - for instance, my channel menu icon used fixed Green and Yellow for the fixed channel colours, whereas now these can be changed at will. Maybe The Autoset, Run/stop and single trigger icons might be improved, but my Autoset, just "AS" isn't great. I'm still not sure about the lightning bolt for 'trigger', but I'm not sure I have any particularly helpful replacement idea. He clearly reads this thread, even if he doesn't post here. He (or anyone) is, of course welcome to use any icons he wishes, I'll put a zip file below.

I've put screenshots of the original Owon, My icons (before Florent's menu structure changes), and Florent's below. His are still way more comprehensible than Owon's. Frankly, I prefer his to mine.

[indman]

@Gyro I understand that everyone has their own preferences and tastes!
It would be very nice if the user could choose a design from several options. Example Owon made a choice between blue and black skin.

[Gyro]

Agreed - at least Florent chose the black theme, the Owon Blue one was horrible! (my personal opinion anyway )

Of course it is possible for users to unzip the owon-vds-tiny-1.0.33-cf12.jar and replace icons in the images folder without any sort of re-compiling issues. I might still play around with a few of them, but only really for 'fun'.

[indman]

My opinion is that the mode icons should be understandable to the user without additional decoding of the designation. From this point of view, the icons from Gyro are the most preferable for me. Another expressive Save / Pin icon is missing. I would leave the "Measure" icon as in florentbr, just make it colored.

[Gyro]

I've extracted the icons and will have a play (I hate editing anti-aliased images ). I'll submit to Florent when / if I manage to come up with a nicer drop-in set. I'll screenshot here first.

P.S. I noticed that the blue theme icon set is still there, but not edited - I can't fault him for that!

[shaling]

Hi,
I recently bought a Picoscope and have just found out that in AC coupling mode, with a x10 probe, the DC signal is not attenuated so is limited to 40VDC. They explain,

"In AC mode the blocking capacitor is switched in before the 1M input impedance of the scope. AC signals will be attenuated by a factor of 10, but from a DC point of view the input impedance of the scope is (ideally) infinite due to the capacitor. In other words the input to the scope will see 400V not 40V. I would not worry about a overload at 40V, but 400V could cause problems."

Is this the same for the Owon?

So with x10 probe, can you measure 10VAC on top of 300VDC in AC coupling mode safely?

Thanks.

[Gyro]

A x10 probe is a DC resistive attenuator (with HF compensation). If you switch the scope to AC mode then, yes, the scope (pretty well all scopes) insert a DC blocking capacitor before the 1M resistive input (I believe there are a few that do it after, but they are pretty rare).

Without a DC path, the probe will present the full input DC input voltage to the scope input, effectively it becomes a 9M series resistor with a bit of parasitic capacitance. Whether a scope can withstand this depends on the voltage rating of its AC coupling capacitor. 400V 300V sounds too high for most scopes.

For a 400V 300V rail, the correct probe would be a X100 one rather than a X10 (even if they claim to be rated that high) and measure on DC. If you need more resolution for a small AC signal riding on top of a high DC one, then the safest approach is to use your own external capacitor, of known voltage rating, attached to the DC rail (again using the scope in DC mode) to provide a charge / discharge path.

Now for the safety disclaimers.... If the 400V 300V rail has any significant energy behind it, big reservoir capacitors for instance, then you need to make sure that the capacitor is well over-rated on voltage, and is preferably a safety type and make all connections before energising it and ensure that the scope stays DC mode, with probe. If it is high energy (Class II or above) then you need to look elsewhere - scopes are standard probes are Class I devices. If the rail is, in any way, directly related to Mains then you can't attach the ground clip to Neutral or any non-ground voltage. The only safe probing method is a high voltage differential probe.

The above is general information rather than VDS1022(I) specific, but I wouldn't go stuffing 400V 300V DC into it in AC coupled mode, any more than I would DC (that is, DC without the appropriate X100 probe).

I hope this helps.


P.S. Take a look at Dave's "How not to blow up your scope" video.

[shaling]

I'm mostly interested in measuring ripple on home brew high voltage <=48V COB LED drivers powered by floating bench supply for debugging.

As it's just above 40V limit, and assuming Owon add a margin for derating, is this OK with x10 probe?

Maybe it's worth or safer to change the capacitor under the can just to be sure?

Would an external capacitor circuit just involve a capacitor between probe and scope centres and resistor on scope end to ground? Like 1pF and 10MOhm?

And note taken to connect it all up before powering on.

I'm seen Dave's video but didn't pick up on how that applied to AC coupling mode.

I really appreciate the feedback.

Thanks.

[Gyro]

You're welcome.

It's a while since I watched Dave's video, he was a bit remiss there then.

Yes, at that sort of level a x10 probe (make sure the switch doesn't slip to x1) is fine.

Changing the capacitor under the shield is a tricky one - these days everything is smd and it's difficult to get an smd capacitor that has both high enough capacitance to avoid rolling off at too high a frequency and has a high voltage rating at the same time.

I would put an external cap (wire ended) between the probe tip and the circuit node that you're monitoring. This gives you the opportunity to optimise its value and voltage rating to the task in question. With the probe set to DC coupled, you can treat it as a 10M resistor if using a x10 probe and calculate the RC roll-off to suit the lowest frequency that you're interested in.

One advantage of using a x100 probe (the disadvantage being lower ultimate sensitivity) is that it has a 100M input impedance - so your capacitor value can be an order of magnitude lower for the same cutoff frequency. This neatly meshes with use at higher voltages where you also want to keep the (higher voltage) capacitor value down.

[Dezmond2]

OFFtop 
Buck Boost Converter D3806 -> Output Active [set 3.33V]
Specified freq is 150kHz.

https://easyeda.com/subbbash/D3806-a3308e2429d04687bd07515b512cb7e9

Where does 60Hz come from? Main freq in my country is 50Hz.

[Dezmond2]

With USB 3.0 work faster than 2.0.

@200us

3.0
One active channel ~67Hz sync
Two active channel ~47Hz sync

2.0
One active channel ~28Hz sync
Two active channel ~16Hz sync

[Gyro]

I am sorry, I don't understand what you are measuring here (or your 60Hz issue).

The VDS1022 only requires USB2 Full speed (12Mbps), so can work with very slow systems without any USB buffering issues. It is not capable of data transfer at USB2 High Speed (480Mbps) or faster, so there will should be no difference in the scope performance with USB2 vs USB3. Maybe some system or adapter related issue?

[Dezmond2]

I am sorry, I don't understand what you are measuring here (or your 60Hz issue).

The VDS1022 only requires USB2 Full speed (12Mbps), so can work with very slow systems without any USB buffering issues. It is not capable of data transfer at USB2 High Speed (480Mbps) or faster, so there will should be no difference in the scope performance with USB2 vs USB3. Maybe some system or adapter related issue?

It's output ripple without load.

In manual specified USB 1.1 for 1022(I).
I do not know the reason. Check your sync frequency on different USB ports.

[Dezmond2]

About voltage limit, in manual specified 400V (PK-PK) = 141Vrms, at front panel 400Vpk = 283Vrms...where is wrong?
I think mistake in manual...

[Gyro]

Ah, yes. USB 1.1 Full speed and USB 2 Full speed are the same, 12Mbps.

The voltage rating in the manual is rather confusing - the 400V Pk is with the scope probe set to x10. The maximum input at the BNC sockets is 40VPk.

Please see reply #580 for a slightly more detailed description - including warnings about attempting to scope the mains.

[Dezmond2]

the 400V Pk is with the scope probe set to x10. The maximum input at the BNC sockets is 40VPk.

Please see reply #580 for a slightly more detailed description - including warnings about attempting to scope the mains.

I know about divider in probe for high voltage. I mean differences between Vp and Vpp...in manual Vpp, at front panel Vp.
And how about Waveform Capture Rate for VDS1022...i have info for 2000wfms/sec....but i measured 16-67 from external sync(multi).

[lotas]

PC software for VDS1022 (I) version no. - 1.0.34
http://files.owon.com.cn/software/pc/OWON_VDS_C2_Setup.zip

[Dezmond2]

PC software for VDS1022 (I) version no. - 1.0.34
http://files.owon.com.cn/software/pc/OWON_VDS_C2_Setup.zip

1.0.36

[crai]

I have been testing versions 1.0.34 and 1.0.36 of the software and in summary there is good news and bad news.
- Good news: they come with new versions of the FPGA configuration file: 3.9 and 4.1. Version 3.9 fixes the bug in previous versions where the pulse trigger has the time scale shifted. This version (3.9) works correctly with versions 1.0.33 or earlier of the software. Version 4.1 does not work with previous versions of the software.
- Bad news: In the software 1.0.34 and 1.0.36 they broke the trigger by pulse !! It doesn't work directly with any FPGA configuration file version.
I am using the FPGA v3.9 configuration file with the above software and everything works very well even the pulse trigger.

[Gyro]

Thanks crai. Useful findings.

I notice that V1.0.36 now contains three FPGA configuration files for the VDS1022... FPGAV1_V3.9, FPGAV2_V4.1 and FPGAV3_gaoyun, interesting (I bet the last one is an accidentally released debug version, they've done such things before).*

Oh, how I wish Owon would change their ways, issue release notes and stop using the same download file name for different versions (preventing access to previous versions)! It would be nice to know what changes are going unnoticed (apart from the stuff that they break and fix).

It will be interesting to try the different Config files with florentbr's software.


EDIT:  *I notice that FPGAV2_V4.1 (166kB) and FPGAV3_gaoyun (217kB) are significantly bigger than the standard 147kB which has been constant, right back since V3.2. Maybe these are intended for modified hardware versions using different FPGA devices. This would explain them not working on existing H/W. Just a guess.

[Gyro]

An insight from florentbr on the new FPGA config and V1.0.36 S/W issue...

https://github.com/florentbr/OWON-VDS1022/issues/38#issuecomment-932995785

It does appear that the different config files are for different H/W versions, based on s/n.

[crai]

Thanks Gyro, very interesting information!

[VEGETA]

Hello,

I have done a review for it, check it out here:




I am very happy with it, very reliable and cheap enough for anyone to afford. best beginner scope.

[Gyro]

Nice to see a good intelligent review video - there are very few out there for the 1022I.

There are quite a few shortcuts for added convenience and reduced reliance on the menus, I think I documented most of them in reply #44.

I would highly recommend that you try Florentbr's alternative software. It adds a lot of interface improvements (and even more shortcuts) as well as additional functionality, such as single trigger on very slow timebases. Florent is also very responsive to reasonable feature suggestions.

[VEGETA]

Nice to see a good intelligent review video - there are very few out there for the 1022I.

There are quite a few shortcuts for added convenience and reduced reliance on the menus, I think I documented most of them in reply #44.

I would highly recommend that you try Florentbr's alternative software. It adds a lot of interface improvements (and even more shortcuts) as well as additional functionality, such as single trigger on very slow timebases. Florent is also very responsive to reasonable feature suggestions.

this will be the topic of a future video, thanks

I hope my review gets people started with this awesome cheap and professional scope.