Author Topic: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)  (Read 74864 times)

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Offline Gyro

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #250 on: March 20, 2018, 08:16:45 am »
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.
Chris

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Offline CatWhisker

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #251 on: March 29, 2018, 10:32:40 am »
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".

Poking around at the source, there is no 'phone home' feature - the devs are just leveraging GSON library as a better/cleaner mechanism for storing settings.

That's not to say the Google library isn't itself phoning Google, I havn't looked there yet, but at least Owon are behaving here.


In other news, for OS X users: If anyone wants to try a 'native' style package, grab the WIP archive from https://github.com/tinwhisker/Owon-VDS1022
Notes:
Some features (like 'save to bitmap') doesn't work yet.
Driver install isn't done.
'Help' works (re-packed as a PDF, rather than CHM).
'Update' button removed.
 

Offline Nullarbor

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #252 on: April 01, 2018, 01:44:22 am »
There seems to be a problem with the 1.0.29 Software.

I installed it and tried calibrating again. It gets stuck at the beginning now.
There is no change in behaviour when the netbook is connected to the internet,
so it has nothing to do with my netbook not being online before.

When clicking "cancel" and then "yes" to the stuck calibration procedure, nothing happens. I had to kill it with the task manager.

I deleted all files of the Owon and installed Version 28 again.
The calibration works just fine again in this version.

Any ideas?

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Offline Nullarbor

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #253 on: April 01, 2018, 01:51:22 am »
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.

Thank you Gyro. I will keep an eye on that, hopefully learning more.

Does what you're saying mean that all "normal" NON-ISOLATED oscilloscopes
are somewhat inferior to the isolated ones (which are quite rare)?

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Offline Gyro

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #254 on: April 01, 2018, 02:58:48 am »
Haha, well I think you'd get some get some indignation from folks with "normal" scopes that their units were "somewhat inferior"  ;)

However, yes, any system which involves ground loops, particularly where that loop path passes through mains ground is subject to issues. Audio systems, for instance, tend to suffer from hum problems if audio ground connects to mains ground in both 'sources' and amplifiers. What it does mean is that you need to always take ground loops into account when measuring - one of the reasons why many Bench PSUs have floating output and separate mains ground terminal. The ideal is to have the 'system' reference to mains ground at a single point, often not possible in the real world with several pieces of grounded test equipment and debugging on a piece of equipment that is also mains ground referenced. Not a show stopper, but something certainly to be aware of.

The problem is particularly bad with USB instruments though. Computer USB ports are fairly fragile, the USB spec specifies that the outer braid and connector shells should only be grounded at the PC end so, for instruments that follow the spec, the only ground return path is the little black wire in the USB cable. In fault situations where significant current flows through the earth clip, the black wire fries, followed almost instantly by the USB 5V and data signals! It also means that noise levels can be higher than integrated bench type scopes. That makes the USB isolation in the Owon (I) versions highly desirable, as far as I'm aware they are the only low cost USB scopes that can do this, Hanteks (not sure about the Siglent Analog discovery products I haven't looked into them) and the like like rely on lots of USB bandwidth - beyond the reach of current USB isolator chips.

Sorry, I'm rambling a bit. In terms of noise, it isn't too critical for an 8 bit scope like the VDS1022(I), but the isolation does give some benefit and most importantly in protecting the PC from damage. Any situation where a low voltage low impedance current could potentially flow through the ground loop will benefit from isolation.

Once you get into the realms of sensitive or precision measurements are involved, then various measures become applicable, I mentioned single point system grounding, there are also differential probes for common mode rejection, decent bench meters have floating inputs with a separate guard terminal, both screened from mains ground, etc.

Thanks for flagging the bug in the 1.0.29 S/W it adds to the group inteligence in lieu of release notes! - Owon do seem pretty accident prone. You may have seen a few posts back, that I uploaded my collection of previous S/W versions  (I see it still has a week to run). If you have any problems with 1.0.28, then I used 1.0.23 for a long time without noticing any issues... https://uploadfiles.io/70a4d (appropriate virus check cautions apply!).
« Last Edit: April 01, 2018, 03:27:39 am by Gyro »
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Offline Riaj159

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #255 on: July 12, 2018, 04:49:25 am »
recently i have opened up my OWON VDS1022(non isolation version) as there was nothing left in my home for teardown & discovered that copper strip is not making any contact with the outer shell that should act as a Electromagnetic shield. i have fixed that issue,all owner of OWON VDS1022/OWON VDS1022i should check for it.also discovered  that lowest volts/div(5mv) without any probe the amount of average noise vpp&vrms depends on the computer/laptop usb ports. some ports induce less noise,some ports induce more noise,you have to discover which usb port is best for your lowest volts/div measurement.some channel are also by born more noise free then other channel,for example my channel 1 with settings(5mv volts/div,1ms,DC,without any probe,persistence: infinite & make sure that other channel is off.if you turn on other channel or turn on other channel and make it off again in that case you will not get much lower sensitivity until you power off the device and turn on with only that by born less noisy channel) i can get vpp: .600mv vrms: .138mv where my 2nd channel never reach close to that level what ever i do.Someone have success with owon VDS1022 software to run on OSX & Debian, i have tried on raspbian but no success(software works but device not found),is there any one who have tried owon VDS1022 on Raspberry Pi??? it will be then great DIY  handheld oscilloscope with display & touch interface!
 

Offline Gyro

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #256 on: July 13, 2018, 04:18:48 am »
Interesting input Riaj159,  I guess that copper strip is easily damaged by the sharp front edge of the Aluminium case shell extrusion whenever the board is inserted.

My early revision VDS1022I (photos on page 1 of this thread) didn't have the copper strip fitted, it was a later addition (it was there by the revision that Mark_O purchased). I checked today, and my case is reliably floating relative to the front panel ground.

Your post reminded me that I need to do some noise comparisons on my 'I' version to see what effect grounding the case to input ground has at low levels. On the one hand, the floating case makes accidents less likely, on the other, it may increase noise and if it does suffer insulation breakdown then I'm uncertain what part of the board would be 'struck' first. Not a problem in practice as it would be very bad to float the ground leads on any scope to anywhere near enough voltage to cause insulation breakdown, even a well isolated one.

I'm also curious about the progress on other platforms, it's all gone a bit quiet. I'm now a Raspberry Pi owner too and I agree, it would make a very nice portable touch screen setup.
Chris

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Offline Riaj159

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #257 on: July 13, 2018, 02:50:44 pm »
tnx gyro for reply,I am also interested about the effect of grounding the case on the isolated version.what if i replace the on board 100mhz clock with 125mhz clock for the sake of overclocking the ADC??? my unit have the MXT2088(equivalent to AD9288 ). hantek dso5102p oscilloscope actually use same ADC but let them run at 125mhz by overclocking so that they can achieve 1gsps with 8 ADC(physically 4 AD9288 ).Though 125mhz might not be guaranteed to achievable due to stability in every case & what will be the consequence on the FPGA site is unknown,also owon software might be another issue related to time base(maybe there is hope as owon software released with code? ).currently don't have any 125mhz near clock source,but it’s just a thought...or i'm too greedy for extra bandwidth  ::)  >:D .
 

Offline Gyro

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #258 on: July 14, 2018, 06:05:56 am »
Haha, yes, I think you are too greedy for extra bandwidth - actually you mean sample rate, the bandwidth is a measure of the analogue input stage frequency response and rise time.

I don't know for sure, but I think overclocking at 125MHz without changes to the FPGA code or PC software would lead to some strange results. At minimum I think all the measurements and timebases would be off. I don't think anyone has reverse engineered the FPGA code.
« Last Edit: July 14, 2018, 06:07:27 am by Gyro »
Chris

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Offline Riaj159

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #259 on: July 17, 2018, 09:43:09 pm »
tnx for sharing your opinion gyro :) :) :)
 

Offline noopwafel

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #260 on: August 21, 2018, 06:06:54 pm »
I got a VDS1022I very cheaply from aliexpress recently. It's a nice toy and really portable which is great; thanks for all the commentary in this thread, I appreciated it. Not yet sure if it has actual value as a scope but we'll see.. :)

To talk to it over USB, you just need to upload the bitstream and then send a bunch of pretty simple commands. I started work on a sigrok driver a few days ago; I plan to finish+upstream it, but just in case I get bored first then I'll keep the unfinished code on my github for anyone who comes after me (right now it's a mess which just hard-codes all the settings, but hey, the signal *looks* OK in pulseview as long as you don't look at the scale).

It looks like the VDS1022(I), the VDS2052 and the RDS1021 are all very similar ('tiny' models), with this 5K internal buffer on an internal MCU. They seem to need slightly different commands but hopefully adding support for the other models should be simple enough if anyone ever wants this. :)

The higher-end models ('smart' models: VDS 2062,2064,3102,3104) seem to be very different, and they talk SCPI instead.
 

Offline svetlov

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #261 on: August 26, 2018, 02:13:08 am »
 Hello dear! How can you solve the problem of spontaneous disconnection of 1022 from the control program in a few minutes   use? the device I have more than two years and this problem is not corrected with the update of the software - this is repeated on different    computers under Windows 10
Thank you ::)
 

Offline nzasch

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #262 on: September 07, 2018, 01:26:44 am »
@noopwafel have you managed to initialize it following the "OWON Oscilloscope PC Guidance Manual" ?
 

Offline noopwafel

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #263 on: September 07, 2018, 06:47:44 pm »
Quote from: nzasch on Today at 01:26:44 am
@noopwafel have you managed to initialize it following the "OWON Oscilloscope PC Guidance Manual" ?


No, the 'tiny' scopes don't seem to support anything that complicated, they just provide chunks of raw data from the FPGA and you need to do quite a lot of initialization/configuration (including uploading the FPGA bitstream and downloading the calibration data - they don't even handle the calibration internally). They will reset themselves (which I guess might be responsible for disconnections) if the host doesn't send a command for more than a few seconds, or the communication desynchronizes. My VDS1022I will keep capturing for quite a long time (via USB2) via my sigrok driver without any apparent problems, but I didn't try the Windows software for more than a few minutes (just enough to get a packet capture).
 

Offline nzasch

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #264 on: September 11, 2018, 08:33:01 pm »
I'm trying to write a C client with libusb for measurements, but after finding+opening the device, the device reply is the same whatever command I send (START, STARTBIN ecc). if I try to bulkread the data, it gives usb timeout.
 

Offline AbirFaisal

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #265 on: September 19, 2018, 12:33:44 pm »
I'm trying to write a C client with libusb for measurements, but after finding+opening the device, the device reply is the same whatever command I send (START, STARTBIN ecc). if I try to bulkread the data, it gives usb timeout.


This is an older version of the OWON software which includes the original source code. Create a breakpoint in the Main file in owon.vds.tiny then debug it. When you get to the initialization code watch the steps carefully and emulate it in your own software.



https://github.com/tinwhisker/Owon-VDS1022/blob/129a3b4582030e3c52d49969dcf5059f0e2a3fb6/Owon-VDS1022-OSX.zip


As a side not they have Chinese comments in the code which I put through google translate. One of the comments speak about porting to Android so I wonder when they'll have that ready. 1022i + Cheap android tablet + battery pack is basically like having a handheld portable oscilloscope.





Quote from: nzasch on Today at 01:26:44 am
@noopwafel have you managed to initialize it following the "OWON Oscilloscope PC Guidance Manual" ?


No, the 'tiny' scopes don't seem to support anything that complicated, they just provide chunks of raw data from the FPGA and you need to do quite a lot of initialization/configuration (including uploading the FPGA bitstream and downloading the calibration data - they don't even handle the calibration internally). They will reset themselves (which I guess might be responsible for disconnections) if the host doesn't send a command for more than a few seconds, or the communication desynchronizes. My VDS1022I will keep capturing for quite a long time (via USB2) via my sigrok driver without any apparent problems, but I didn't try the Windows software for more than a few minutes (just enough to get a packet capture).


noopwafel can you quickly describe your build environment? I can't seem to get your libsigrok working. Not asking for much I just want to know exactly what versions of pulseview, libsigrokdecode, libserialport that you are using so I can get it to work with your driver. Thanks.

 

Offline AbirFaisal

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Offline Pluscrafter

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #267 on: October 12, 2018, 05:35:17 am »
Had anyone get the VDS 1022I worked on Linux? I've use Ubuntu 18.04.1 and had tried https://github.com/tinwhisker/Owon-VDS1022 and it doesn't work after following the instructions. My lsusb shows my scope as a Owon PDS6062T.
 

Offline Gyro

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #268 on: October 20, 2018, 11:33:18 pm »
I've just noticed that version 1.0.30 of the VDS1022(i) windows s/w is up on the Owon site, it's apparently been there since July. As usual, no release notes but it hopefully fixes problems in 1.0.29.

I've installed it but not hooked it up to the scope yet - I can't see any feature differences though.

http://www.owon.com.hk/supports_pc_software
« Last Edit: October 20, 2018, 11:41:02 pm by Gyro »
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Offline CatWhisker

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #269 on: October 27, 2018, 03:46:28 am »
Had anyone get the VDS 1022I worked on Linux? I've use Ubuntu 18.04.1 and had tried https://github.com/tinwhisker/Owon-VDS1022 and it doesn't work after following the instructions. My lsusb shows my scope as a Owon PDS6062T.

FYI, the "PDS6062T" listing is just part of the lookup table in the Linux kernel, because it shares the same PID/VID. AFAIK, that's all it shares though.
We could possibly email the usb id's maintainer to make it generic? PDS6062T Oscilloscope -> OWON USB Oscilloscope
http://www.linux-usb.org/usb.ids

GreySpammer-Tir had success/progress I believe in getting the USB driver working:
https://github.com/tinwhisker/Owon-VDS1022/issues/6#issuecomment-433426973

I'm yet to find time to revisit the Linux package, but I'll probably sort a script over the holiday period.
 

Offline Pluscrafter

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Re: OWON VDS1022I Quick Teardown (versus the Hantek 6022be)
« Reply #270 on: October 27, 2018, 03:49:11 am »
Had anyone get the VDS 1022I worked on Linux? I've use Ubuntu 18.04.1 and had tried https://github.com/tinwhisker/Owon-VDS1022 and it doesn't work after following the instructions. My lsusb shows my scope as a Owon PDS6062T.

FYI, the "PDS6062T" listing is just part of the lookup table in the Linux kernel, because it shares the same PID/VID. AFAIK, that's all it shares though.
We could possibly email the usb id's maintainer to make it generic? PDS6062T Oscilloscope -> OWON USB Oscilloscope
http://www.linux-usb.org/usb.ids

GreySpammer-Tir had success/progress I believe in getting the USB driver working:
https://github.com/tinwhisker/Owon-VDS1022/issues/6#issuecomment-433426973

I'm yet to find time to revisit the Linux package, but I'll probably sort a script over the holiday period.
That would be very appreciating :)

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