Author Topic: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)  (Read 126152 times)

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Online Gyro

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #225 on: February 17, 2018, 05:41:30 pm »
I do not mean to seem unkind on your first post, but it is said out of concern. Connecting a scope probe input directly across the mains was a really stupid thing to do! You are not the first newbie to do it though, the mains seems like a magnet to some people :palm:! You should feel very lucky that you didn't do yourself serious harm! Equipment is replaceable, you are not.

Please refer to this video of Dave's to understand what you did...

https://youtu.be/xaELqAo4kkQ


The same bang would have occurred whatever scope you used. You were unlucky enough to be using a USB one, which extended the damage to the PC too. The USB isolated version (the VDS1022I) would have protected the scope and the PC from damage, but you would still have been at serious risk of electric shock, shorting the mains with your ground clip probably saved you from that. From your list, it sounds like an expensive lesson.

It's very hard to predict what on your scope has been damaged - the mains current will have passed through the ground clip of your scope probe, through the circuit board and via the ground signal of the USB interface to your PC motherboard and the PC Earth connection.

Given the level of damage to the PC, I would expect a similar level of damage to the VDS1022. I would suspect that the chip associated with the USB interface has also been destroyed. I don't know what you are measuring when you say "Now on board side it shows 0.3 ohm." or whether you have replaced the exploded resistors with the correct values. There is no published schematic, so it is difficult to specify individual component IDs that might be affected (I do not have the same board Rev as you). Maybe you can post a photo showing those resistor locations.

If you check that none of the pins of the USB connector (apart from the ground pin) are shorted to ground, then you might try connecting it to the PC and seeing if it is recognized. PC USB ports are quite well protected (apart from shorting mains into them!), but unplug at the first sign of an error message. The driver will need to be installed of course.

If the VDS1022 is still recognized then it should be possible to start testing other functions using a safe signal source., eg, the probe calibration output or a cheap ebay function generator. Given the cost you have already incurred, I would recommend getting the USB isolated version (which still won't make it safe to scope the mains, but will protect the PC from accidentally introducing large low voltage currents via the ground clips).


Edit: I have been re-reading your post and am finding it a bit confusing when you say "just bought" - are you saying that you already have it working again after damaging it with the mains short and are now having triggering problems? If so, were you having them when you first got it?
« Last Edit: February 17, 2018, 06:38:16 pm by Gyro »
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Offline VitaliyKrym

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #226 on: February 17, 2018, 07:31:21 pm »
I'm not newbie but what I did was really stupid. I don't you scope much. I did not realize the 10:1 probe has one simple resistor and ground goes direct. 0.3 \$\Omega\$measured between 0 and 5v chips supply. The reason I need to see 110/220V. I bought device should be supply 220V 50Hz. and I'm making inverter to meet my needs.
Originally exploded resistors are 0 \$\Omega\$. I put 10 \$\Omega\$ for testing. So all 5V drops across this resistors.
After I bought it I tested in with low voltage signal and found out that picture is no steady. Connected to USB3.0 it cannot be even seen. Much better on USB2.0. And it nothing changes with different trigger level. Would it be possible  the U12 was not install during manufacturing and as result not steady picture. If you give me your e-mail I can send full size board pictures.
« Last Edit: February 17, 2018, 07:45:59 pm by VitaliyKrym »
 

Online Gyro

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #227 on: February 17, 2018, 08:16:59 pm »
Ok, I get the picture, I think...

I managed to located R105 at least on one of Mark_O's photos of his Rev 1.4 board (bottom of page 1 of this thread), it is one of the resistors that links the board ground to the USB ground - it bypasses the gap in the grounds that would be there on the isolated model.

If R105 blew open then all of the mains current will have passed through the logic ICs and supply regulators to the USB signal lines and USB Vbus line to the PC. At the very least this will have destroyed the USB interface logic (inside the CPU) and probably most of the rest of the logic, regulators etc. The 0.3 Ohms that you are reading between +5V and 0V is probably the resistance of your meter leads, the board is probably dead short. I don't see any possibility of salvaging the board in these circumstances - it is fried! [Edit: Slight correction, from your photos... R105 is in the 5V USB supply, R90 and R103 are the USB ground link, from the scorch marks, the ground obviously went first, then the +5V, then the USB signals, that was severe!]

It is too late to understand your triggering problems now, it could well have been a settings issue, trigger level / source etc. It wouldn't have been a USB speed related issue as the VDS1022 only requires low USB speed (USB Full speed, not High Speed).

Regarding U12 being missing, this is an analogue video sync separator chip, only used for video mode triggering. I'm not sure why it wasn't fitted, maybe they removed this functionality, I don't know, it was fitted Mark's Rev 1.4 board. As I say, it wouldn't be needed of any normal triggering modes so wouldn't have been the cause of your problem anyway.

There's obviously no way now to check what trigger settings might have been wrong, or even using the 'autoset' function now, sorry.

Maybe you could talk to Owon about having a board with missing U12, they might be generous about the damage issue.


Edit: I have now seen the photos you added, thanks. It confirms my diagnosis above - there was a lot of current involved.
« Last Edit: February 17, 2018, 08:41:35 pm by Gyro »
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Offline VitaliyKrym

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #228 on: February 18, 2018, 12:56:05 pm »
Thank you for your answer.
I knew the damage is big, at least MC is gone. It is easy to replace it but where to get firmware for it  :-//
Looks like I will get replacement for it (cross fingers) and I don't want to destroy it as well. So here are few questions related to this.
What other differences between 1022 and 1022I exept U37 and U9? What I found else I have metalized sides of board unlike others. This makes oscilloscope case grounded. I was lucky I did not hold it in hands. The strange thing this is same board version.
So on my replacement (if I get it) Im going to install U9 and U37, remove 8 resistors and isolate board from case. Anything else?
I need to be able to see the form of 220V inverter output. VDS1022I rated 400V.
About OWON.
I tried to contact them with no answer.
 

Online Gyro

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #229 on: February 18, 2018, 03:00:27 pm »
You're welcome, sorry it wasn't a more hopeful one. I think it is still Chinese New Year holiday at the moment, so I wouldn't expect a fast answer from Owon.

Even if you could get a replacement microcontroller, I wouldn't be surprised to find wider damage from the mains voltage passing across the chip, eg. The FPGA, or ADC.

Yes, the 'non-Isolated and Isolated versions share the same PCB. The main differences, as you found, are U37 - ADuM3160 USB Isolator,  U9 - TI DCP020505P 2W DC-DC converter, and removing the components that bypass them. There are some supply decoupling capacitors around U37 but I think they are populated by default - check the chip datasheet.

I'm not sure about costs - particularly sourcing the DC-DC converter. I remember someone did their own conversion earlier in the thread but not sure how much they saved relative to the VDS1022 / VDS1022I purchase price difference. There is also the warranty (3yrs?) to consider.

As you have worked out, the metal case is connected to the BNC connector shields, so yes, it would have become live (I would have hoped that a circuit breaker would have popped by that point, given the level of damage).

I need to be very clear here... The USB isolation is there to protect the scope and the PC against accidental high current ground loops (at low voltage) and to reduce noise pickup from ground loops. Even though the isolation components do have high voltage ratings, it is not intended for floating the scope ground at high voltages! - I would be very stupid to advise you otherwise. Accidents can happen all too easily, as you have found, even when experienced. You could still suffer a very nasty bang and live case if, say, you accidentally connected the ground clip of one probe to Live and the ground clip of the other to Neutral! From your replies, I think you have a good understanding of the risks.

The safe way to scope around mains is with a CAT rated high voltage differential probe... or one of those fancy Fluke portable scopes with individually isolated channels.


P.S. From your second reply it looks as if you are trying to make an "inverter" to power a 220V 50Hz device - I don't know what the device is, but wouldn't a simple step-up transformer do? If it's a 50Hz / 60Hz issue then most things don't care - particularly running a 50Hz device at 60Hz as you are less likely to run into transformer core saturation issues than going to a lower frequency. You ought to be able to sort out phasing on something like that with a meter. Just a thought.
« Last Edit: February 18, 2018, 03:15:00 pm by Gyro »
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Offline VitaliyKrym

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #230 on: February 18, 2018, 03:29:21 pm »
Then why yours vds1022I is rated 400V input voltage (so you ARE able to apply 220v to 10:1 probes) and what is the reason to supply 10:1 probes (600V rated) with VDS1022 (rated 40V) which has 5v/div without devider. Would I have same damages if connected to laptop(not grounded)? Would you recommend me simple schematic of high voltage devider I can use with 220VAC?
Looks like I had 50% chance to destroy it and I took it by connecting ground clip to "L". If I connected it to "N"... To late anyway.
 

Online Gyro

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #231 on: February 18, 2018, 07:04:39 pm »
I agree, the spec is confusing - I understand it as 40V peak input protection at the BNC, 400V peak with the included 10:1 probe. I don't know why they choose to specify it differently for the two scopes - they are obviously the same analogue front end circuits.

Quote
....(so you ARE able to apply 220v to 10:1 probes) and what is the reason to supply 10:1 probes (600V rated)...

Sure you are, although I wouldn't want to push the limits of low cost Chinese scope probes too close to their limits - That's NOT the same as connecting it to the Mains though. Most scopes are not CAT rated for mains use... Prospective fault energy (you should know about that by now!), transients etc. That rated voltage is probe tip relative to the ground clip - you have no safe place to put the ground clip if you are scoping mains! There's no guarantee that the Neutral is at the same potential as Earth (Ground), especially in supply fault or transient conditions.

Quote
Would I have same damages if connected to laptop(not grounded)?

Yes, the same unsafe situation - if you accidentally connect the ground clip to Live then all exposed metalwork on the laptop (connector shells etc) become live too. That is why the old practice of lifting the mains ground wires on bench scopes is also forbidden.

USB isolation and floating laptop are both used as methods of breaking ground loops to reduce measurement noise or protecting the equipment against damage from reasonable fault situations. Unfortunately any possibility of connecting the ground clip to Mains Live is NOT a reasonable fault situation!

Quote
Would you recommend me simple schematic of high voltage devider I can use with 220VAC?

This is where the High Voltage Differential Probe comes in, as I indicated previously. It has two 'tip' inputs and no ground clip. It safely translates the difference between the inputs into a signal suitable for feeding into grounded scopes. They carry the appropriate CAT safety ratings.


Direct scoping of the mains is a pretty uncommon thing to do. People who do it are usually equipped with the appropriately CAT rated equipment eg. at least CAT II, 300V for your situation. (MOST scopes are not CAT safety rated). When working on mains equipment an alternative is to use a mains safety isolating transformer to power the DUT (Device under Test), this has it's own risks but the rule is that you always use the isolating transformer to power the DUT, not the test equipment. Using an isolating transformer carries its own risks and need for precautions.

Please review the "How not to blow up your scope" video that I linked (I seem to be doing all the work here) - it covers most of the issues we are talking about here. There are many other safety related threads (including use of Safety Isolation transformers) if you do a forum search.
« Last Edit: February 18, 2018, 07:16:29 pm by Gyro »
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Offline fourtytwo42

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #232 on: March 12, 2018, 04:35:31 pm »
Just noticed OWON VDS1022 software revision increased from 1.0.27 to 1.0.28 not sure when it happened, no revision history, downloaded it and have yet to spot the differance :)
 

Offline Daruosha

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #233 on: March 12, 2018, 05:41:30 pm »
Just noticed OWON VDS1022 software revision increased from 1.0.27 to 1.0.28 not sure when it happened, no revision history, downloaded it and have yet to spot the differance :)

Perhaps they just fixed a Chinese word spelling and released a new minor release. They are the most laziest T&M manufacture when it comes to supporting and improving their firmwares and softwares.

I don't understand why people buy their stuff and how they are still in the business.
 
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Online Gyro

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #234 on: March 12, 2018, 09:08:12 pm »
Just noticed OWON VDS1022 software revision increased from 1.0.27 to 1.0.28 not sure when it happened, no revision history, downloaded it and have yet to spot the differance :)

This version got first got flagged by Nullarbour back in October last year (Reply #211). The main difference seems to be to repair a bug in skin selection that they screwed up in 1.0.27, which previously worked fine! ...

...
The difference in graphics that you show is due to the Black skin being used rather than the Blue one (it can be changed at the top of the Utilities panel). Ironically the only difference I've found so far (versus V1.0.23) is that changing the skin setting seems to have been broken in V1.0.27 and then fixed again in V1.0.28! :wtf:
...

I've been running V1.0.28 since then without significant problems - I think I encountered a crash when trying to stop and save an image. I can't remember the detail now but it don't think it happened on V1.0.23.

I have copies of the released (there are gaps) s/w distributions going back to V1.0.4 if anyone wants to play detective (it's interesting to open the .exe files as archives using 7zip or whatever and look inside). I don't think it's worth using anything before V1.0.23 which I've never found a bug in,  V1.0.11 at the very earliest (that one, I know, fixed a menu bug that I reported), V1.0.27 as I said, has the skin selection bug.

It really is annoying that they don't publish a change log!


EDIT: I may as well upload anyway - it would be useful if a few other people also had backups in case of loss. Run whatever scans you feel appropriate, I've run AVG and Malwarebytes on them....

https://ufile.io/70a4d  (Available for 30 days)
« Last Edit: March 12, 2018, 11:05:29 pm by Gyro »
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Offline CatWhisker

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #235 on: March 16, 2018, 12:29:13 am »
Just for fun: OS X updates

https://github.com/tinwhisker/Owon-VDS1022

Busy year, so this got neglected. But I had a fresh install of 'macOS' (10.13.3) and thought I'd plug the scope in and fix up the scripts.

Fixes:
- Dumb typo - 'Owen'  :wtf:
- Latest 1.0.29 release.
- Added missing usbLib files.
- Changed the bootstrap script from pure 'bash' to AppleScript & 'bash' to simplify the driver install*.

(* I think later OS X builds are stricter for arbitrary folder access, so we need to elevate the privileges when copying the usblib files. Using just bash would never show the sudo password prompt, so instead it'll prompt to run the script instead.)

Remember to run a calibration.
 

Offline CatWhisker

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #236 on: March 16, 2018, 12:34:22 am »
I spotted 1.0.23 -> 1.0.29 that 'com.google.gson_2.1.0.v201203072145.jar' has appeared.
Are they calling home now?

I hadn't seen/used any build between those versions, so dont know when it was added.
 

Offline piotr99

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #237 on: March 18, 2018, 01:49:17 pm »
Just for fun: OS X updates
https://github.com/tinwhisker/Owon-VDS1022
Busy year, so this got neglected. But I had a fresh install of 'macOS' (10.13.3) and thought I'd plug the scope in and fix up the scripts.

CatWhisker many thanks for the upgrade.

I don't have VDS1022 yet but I plan to buy it. I have just installed the application on my MacBook Air according to your description.
It seems to be working properly, but I had to change the folder as below:

OSX:
Copy libusbpp-legacy-0.1.4.dylib to /opt/local/lib/libusb-legacy/ (Note: On OS X, these folders may need creating)
Copy libusb-0.1.4.dylib to /usr/local/lib
 

Offline The_Boots

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #238 on: March 18, 2018, 07:57:29 pm »
Question for any 1022 owners: I just got one of these, but it periodically pops an error message up and had to reconnect. I'm assuming that's not normal, but thought I'd check if anyone else has this issue.
 

Offline CatWhisker

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #239 on: March 18, 2018, 08:13:24 pm »
It seems to be working properly, but I had to change the folder as below:

Copy libusb-0.1.4.dylib to /usr/local/lib

That should only apply only to the manual install guide. Thanks for spotting that.

Most OS X users should just grab the Owon-VDS-OSX.zip and use that.
 

Online Gyro

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #240 on: March 18, 2018, 08:27:53 pm »
Question for any 1022 owners: I just got one of these, but it periodically pops an error message up and had to reconnect. I'm assuming that's not normal, but thought I'd check if anyone else has this issue.

No, not a common problem I don't think. The 1022 is very undemanding in terms of USB bandwidth etc.

A couple of points that come to mind...

- USB port, try another one. Maybe the socket has got loose and is glitching the power. Does wiggling the USB connector provoke anything?  Power requirement is under 400mA so shouldn't be an issue, even for older laptops.

- Assuming that you do not have the USB isolated 1022I, do you have a ground loop that is injecting current via the USB ground. Does it coincide with attaching probe ground clips, does it still happen with probes isolated.

- What os version and S/W version are you running? Does anything in particular provoke the problem?

That's about all I can think of, off hand.
« Last Edit: March 18, 2018, 08:30:01 pm by Gyro »
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Offline VitaliyKrym

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #241 on: March 18, 2018, 10:40:49 pm »
I had same issue with periodical reconnecting. After I converted it to "I" this issue disappeared. 
 

Offline The_Boots

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #242 on: March 18, 2018, 11:07:39 pm »
Yes, it happens with other USB ports, no it doesn't happen when I jiggle the USB cable.

I'm not entirely surprised. I got it used directly from Amazon ("Like new"). I think it was returned, and I may have an explanation why.  :)
So much for getting a good deal, now I need to decide what I'm going to do for a working Oscilloscope...
 

Offline The_Boots

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #243 on: March 19, 2018, 12:47:39 am »
Good to know. Due to various circumstances, Amazon offered to send me a non-used one, and they said since the shipping on a 1022 put it over the price of an I, they ended up sending me the isolated version. Can't complain. Hopefully it solves my problem, too!
 

Online Gyro

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #244 on: March 19, 2018, 10:16:38 am »
Quote
... and they said since the shipping on a 1022 put it over the price of an I, they ended up sending me the isolated version.

That sounds like a win!  :-+

Ground loops can be a real issue for any non-isolated usb connected equipment - up to and including total destruction of the scope and PC (see Reply #225 as just one extreme example).

 You may want to investigate a little further - try putting a meter between a connector shield on your computer and to point where you were connecting your ground clip and see if there is any voltage present (DC and AC). It may give an insight into the possible ground loop path. It's a worthwhile exercise (educational at least) in case you pick up a low cost logic analyser or other equipment. I suspect that in your case, the voltage will be very low, but the loop resistance is also low, so surprising currents can still flow, enough to disrupt USB comms.
« Last Edit: March 19, 2018, 10:24:24 am by Gyro »
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Offline CatWhisker

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #245 on: March 19, 2018, 03:56:26 pm »
Question for any 1022 owners: I just got one of these, but it periodically pops an error message up and had to reconnect. I'm assuming that's not normal, but thought I'd check if anyone else has this issue.
No, not a common problem I don't think. The 1022 is very undemanding in terms of USB bandwidth etc.

I second this. I had mine running for the last ~4 hours to check if it happened to me - still stable.

Rather than another USB port, I suggest another PC if possible - drivers, internal hubs, shared chipset - can be a pig if the device is easily startled.
Especially if you have any funky USB stuff installed (USB sniffers, Wireshark USB tools, VM tools and the like).

FYI: Using 1.0.29 build on OS X.
 
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Offline Nullarbor

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #246 on: March 19, 2018, 08:11:55 pm »
...
- Latest 1.0.29 release.

Remember to run a calibration. ...

I don't have apple stuff, but nonetheless thank you CatWhisker for the info on the latest release AND ESPECIALLY the reminder to recalibrate.

I was having problems with my OWON 1022:

- DC levels were off by a long shot (showing say 9 volts instead of 5 volts)
- When in AC mode, the NULL level of the traces shifted up in steps when changing
  sensitivity (50mV, 100mV, etc). This repeated itself starting with 1V again from NULL. That was strange, so I decided to look here.

I thought my Owon hat gotten defective and was contemplating calling the vendor.
I installed the 1.0.29 software and went into the calibration mode.
It got stuck there on about 20% of the bar. I left it on for an hour.

Frustrated, I re-booted and erased all traces of the OWON software on the Netbook and Registry (it's windows 7).
In hindsight: this Netbook has no access to the internet, so it might have to do with this, since you mentioned the new version may want to "phone home".
Well spotted if I may say!

I installed version 28 and went into calibration mode. It went well and the DC levels
are correct again and the the AC levels at NULL are solid now too when switching through the voltage range.

I was very relieved about this, but have no clue as to what had gone wrong.

If something like this happens again I will film it.
 

Offline Nullarbor

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #247 on: March 19, 2018, 08:16:44 pm »
Question for any 1022 owners: I just got one of these, but it periodically pops an error message up and had to reconnect. I'm assuming that's not normal, but thought I'd check if anyone else has this issue.

I have this problem, but rarely. I just unplug and plug in again.
 

Offline Nullarbor

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #248 on: March 19, 2018, 08:25:27 pm »
Quote
... and they said since the shipping on a 1022 put it over the price of an I, they ended up sending me the isolated version.

That sounds like a win!  :-+

Ground loops can be a real issue for any non-isolated usb connected equipment - up to and including total destruction of the scope and PC (see Reply #225 as just one extreme example).

 You may want to investigate a little further - try putting a meter between a connector shield on your computer and to point where you were connecting your ground clip and see if there is any voltage present (DC and AC). It may give an insight into the possible ground loop path. It's a worthwhile exercise (educational at least) in case you pick up a low cost logic analyser or other equipment. I suspect that in your case, the voltage will be very low, but the loop resistance is also low, so surprising currents can still flow, enough to disrupt USB comms.

Interesting!
I just measured this with my simple means and get the following values:
32mV (from USB metal to probe GND)
2.4mA (from USB metal to probe GND)

Hope I measured this right.
 

Online Gyro

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #249 on: March 19, 2018, 09:16:45 pm »
Interesting, as you say. The 32mV measurement confirms that there are no floating supplies, Y cap leakages etc. involved, ie. everything is grounded.

The fact that you were able to measure 2.4mA though a DMM current range (with its reasonably high value internal shunt resistor) implies that with a low impedance connection through the ground clip and PC ground the current could be significantly higher. It shows that 'Ground' really never is, when you consider voltage drops across current carrying conductors. There might also be some higher frequency currents involved that your meter wouldn't be able to detect.

This sort of low voltage, low impedance, hash is just the sort of thing that USB isolation is useful for, both to prevent circulating ground currents and reducing measurement noise.
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"Victor Meldrew, the Crimson Avenger!"
 


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