OWON VDS1022I Quick Teardown (versus the Hantek 6022be)

[Gyro]

Hmm, I've never seen a 'white label' one. From the look of it, it's no cheaper than a genuine one, so I suspect that it is original H/W.

Glad you've got it working as advertised, and on a Macbook.

The scope probe X1 / X10 thing is common to all scopes and all switchable scope probes. Basically, in X1, the probe tip exhibits the full capacitance of the probe cable plus the input capacitance of the scope (probably about 100pF in total) and the scope 1M ohm input resistance. This limits the useable bandwidth of the probe to very low frequencies, certainly not above audio - depending on the source impedance.

In the X10 position, the probe is configured as a 10M Ohm high impedance voltage divider, 9M Ohms in the probe tip (plus a bit of capacitance) combined with the 1M ohm input resistance of the scope. The Input capacitance at the probe tip is reduced by approximately the same ratio (around 10-15pF), making it suitable for high frequency use with minimal circuit loading.

Do a forum search of variations of 'scope probe switchable, X1,X10' etc. and you will get loads of hits. It's a fairly common question.

The X1 position is pretty useless unless you need a bit of extra low frequency sensitivity, but you could just as easily use a BNC clip lead and get the same performance. It is best practice to keep the probes switched to X10 (there is a probe division menu in the scope s/w [EDIT: Channel Menu, Probe Rate] so that all the readings come out correctly), for the reason above, and to provide additional useful protection to the scope inputs. The switches tend to be a reliability liability too, I don't know why switchable probes are so common (you can get dedicated X10 probes... and X100 probes for high voltage or low loading use).

Don't forget to adjust the probe compensation trimmers to give a proper square wave on the X10 setting, using the scope Cal output, before using them in anger. That should be documented in the manual too.

[Ben23]

Very interesting, thanks Gyro. For voltages within the range that can be safely read by both 1X and 10X, I would have expected 1X to be the better choice. I clearly have a lot of learning to do! I did notice I got cleaner traces of the test signal in 10X than 1X.

I've done the probe compensation, thanks.

How close should the 5V test output be to 5V? It's reading as 4.800V on mine (Vamp). I also have a slight difference / DC offset of about 80mV between the two channels' readings, which repeated Auto Calibration runs haven't fixed (it's the channels that are reading differently, not the probes, as the same channel remains higher when the probes are swapped), so I'm wondering whether I need to go into that hidden menu to manually tweak it...

Edit: The difference between the channels appears to be differing amounts of noise, as it's still present when nothing is connected, and always reads roughly the same amount in percentage terms. i.e. if the display is set to 5V/div, it will read say 200-400mV of noise, whereas if it's set to 5mV/div, it will read 0.2-0.4mV.

[Gyro]

Glad it helped. 

The 5V test output is derived from the USB supply (well at least the isolated DC-DC converter which isolates the USB on the VDS1022I). As such, it is not that well regulated and will vary a bit with USB port voltage, USB cable drop etc. That's not an issue in practice - it is intended purely as a nice clean square wave for probe compensation rather than a voltage calibration source. It does sound a little bit low though.

The auto calibration (as I understand it) uses mainly factory calibration settings which are stored in Flash memory in the unit for amplitude, and concentrates mostly on voltage zero and zero offset adjustments. Yes, you can use the hidden calibration menu to fine tune the settings (I found that I can improve slightly on the Autocal on my unit), and FlorentBR's description makes the differentiation between Zero amplitude and Zero offset settings clearer than we previously understood. You can use a PSU+DMM to calibrate the V/div settings (one time where using X1 probe setting is useful because the highest range becomes 5V/div rather than 50V/div).

Don't get too hung up on the noise measurement values changing as you change ranges - remember that, like most DSOs, the scope uses an 8 bit ADC (ie. 256 discrete levels full scale - negative max to positive max of the range), so will never be as DC accurate as an average DMM. When you change ranges, the significance of a couple of ADC bits changing is scaled accordingly in the readout. ie. you see the same couple of bits interpreted as 0.4mV on the lowest range and 400mV on the highest.

For absolute voltage accuracy, a DMM will always be superior, but for seeing what a signal actually looks like, you can't beat the scope.

[Ben23]

For absolute voltage accuracy, a DMM will always be superior

You haven't seen my DMM

[Gyro]

I'm willing to bet that it has more than 8 bit resolution though. 

[Nullarbor]

Hello again. I am still enjoying my Owon 1022, but seem to have a "problem" with the TTL external input for triggering.

I can't get it to work - don't know if it's my ineptness or something else.

Has anyone here tried using the EXT as a trigger? Any ideas?

My input signal is a square wave 32us wide and goes from 0v to +9.6v and back down again.

[Gyro]

A quick thought - have you been into the Utility menu and set the 'Multi' to Trigger In? I think it defaults to trigger out.

[cosmin1]

Hi guys.
Thanks for tones of info i could find in this topic. It answered a lot of my questions and i'm almost convinced to buy the 1022i.
I would appreciate more customizable skin and trace color, to look better like the real oscilloscopes.

That's why i also find interesting the Loto OSCA02, but there isn't any info about it. This means isn't worth the money?
Price is 20$ more than the Owon.

[Gyro]

That's a new one, I haven't seen it before. As you say, there doesn't seem to be much info around. I found a youtube video on it...

...which indicates that it 100Msps like the Owon (don't know if that's per channel or shared). It adds basic 6 bit logic analyser / GPIO capability, data logging (which could be useful), and a 48k buffer (Owon is 5k).  Basic edge triggering only. I don't think it has galvanic isolation though, but I was skipping through the video a bit.

He is raving about the UI in the video, comparing it with the Hantek 6022, I don't think he mentioned the Owon at all. I'm not a fan of on-screen virtual knobs, but that's a personal preference thing. It looks fairly understandable though. He seems to think that FFT and Autoset button are unique features? Huh?  Something screwy seems to happen when he switches from sinewave to squarewave at 1MHz too (15:48), he has to wind down his generator frequency to get it to display. I'm not sure what the flashing warning triangle is about?

I'd be interested to see a teardown to see how much it's doing on board and how much in the PC -  it must be doing something because it mentions the 48k buffer, whereas Hantek claims 1MB, but that's just the arbitrary size of the buffer in the PC that it streams data into in realtime (so effectively the Hantek has none on the device).

It's probably worth you starting a new thread to discuss it so that replies on the different scopes don't get confused.


P.S. Here's a manufacturer video, looks quite good but you need some patience...

https://youtu.be/mUM9R6rnH90

[cosmin1]

Hello.
As i said, i already ordered the Owon VDS1022i.
Now i just want to install the florentbr's version software with customizable trace colour, to play with it and familiarize myself with the menus.

I follow exactly the indications in Readme file, but all i get is the next error and no app is installing.

## Install
Download and extract the following archive: 
https://github.com/florentbr/OWON-VDS1022/archive/master.zip
Right click on `install-win.cmd` and select "Run as administrator". 
The script installs the drivers, copies the files, registers for uninstall and creates a menu entry.

Am i doing something wrong?
My OS is Windows7 64bit.

[Gyro]

I think you mean florentbr's s/w. 

P.S.   F:\  looks a bit strange unless you have lots of drives?

P.P.S. It may be because you don't have any hardware to attach yet. I'm not sure how I would go about manually installing a driver in device manager if the hardware wasn't already connected. I think it will also automatically pick up the driver from Camomille's installation when you plug it in.

[Gyro]

My Application Shortcut is:

%JAVA_HOME%\bin\javaw.exe -Djava.library.path="C:\Program Files\OwonVdsTiny\lib" -Duser.dir="%APPDATA%\OwonVdsTiny" -cp "C:\Program Files\OwonVdsTiny\jar\*" com.owon.vds.tiny.Main

(It should have been put as an entry in your start menu by the installer script)

[Gyro]

I was hoping that it had got that far before failing to install the driver. Sorry, I wouldn't have a clue where to start with remote access.

[indman]

cosmin1 Unzip,copy this file in folder OWON-VDS1022-master and run my modified install-win.cmd without installing the driver. Show me the black window after running this script.

[cosmin1]

Oh yeaaaaaaaaaaaah!
That's what i'm talking about. 

So the old install-win was bad.
Now everything's different. Thank you very much!
I suppose now i can uninstall the original 1.0.30, right?

[Gyro]

Nice wallpaper! 

[cosmin1]

Thanks Gyro! 
One more question. Can't see anywhere the background colour setting. I lost it?

[Gyro]

That's one you're going to have to wait for (maybe), I don't know if florentbr is planning to make that customizable too at some point. Owon used to offer 2 skins (Black and Blue) which he has removed in favour of individual colour settings, but they were both black background for the screen.

The black background is pretty much standard for scopes DSOs (apart from old mono LCD Tek ones and Picoscope). I think it give best trace contrast anyway, especially by the time you have measurements, cursors, math channel etc. up at the same time.

[cosmin1]

Oh... i see.
I thought i read somewhere about changeable background too, but maybe i'm wrong.
Thanks again.

[indman]

I suppose now i can uninstall the original 1.0.30, right?

I 'm glad you did well!
Uninstall the original version will also remove the USB driver from the system! So when you get your hardware Owon and plug it in, you 'll need to have those drivers in your system.
They can be installed separately if you save the USBDRV folder from the installed original 1.30 VDS_C2
I also suggest you delete your previous version installation messages from florentbr to avoid clogging unnecessary information with this topic. I will also delete my messages except one that contains a modified install-win.cmd.

[cosmin1]

I shouldn't have deleted the earlier posts...
I received the oscilloscope, insalled the manufacturer software and working fine.
But now i'm trying to install the florentbr's s/w on other laptop and i get this message. Installed Java but still can't install the s/w.
What else can i do?

[cosmin1]

Now everything's installed right but the launcher is nowhere to find. 

[Gyro]

Now everything's installed right but the launcher is nowhere to find. 

Try creating a shortcut with...

 %JAVA_HOME%\bin\javaw.exe -Djava.library.path="C:\Program Files\OwonVdsTiny\lib" -Duser.dir="%APPDATA%\OwonVdsTiny" -cp "C:\Program Files\OwonVdsTiny\jar\*" com.owon.vds.tiny.Main

(It should already be in your start menu - it says it created it)


P.S. Please try not to get angry about it. It's not as if the florentbr s/w something you're paying for, you already have the working product software! 

[cosmin1]

I'm angry about my laptop, not about the software.
Will try to do that.

[Gyro]

Ah ok, it's perfectly normal to get annoyed at computers from time to time. 

I'm interested to know if the shortcut worked - you ought to find the one on your other computer to be identical (I think).

The only I thing I remember from your previous deleted installation posts was that it was important not to rename anything (folders etc.), after that, my memory fails me.


P.S. Reply #573 still contains the zip file from Indman which seemed to sort you out last time.