OWON VDS1022I Quick Teardown (versus the Hantek 6022be)

[LiquidMK]

SIBtronics, thanks! I did corrections that you proposed in .py files and got measurement of my RS-485 data. Unfortunately I'm absolute newbie in python, so I don't understand how to start "decode_uart" function.. 
Also I see that RS-485 measured by only one probe of VDS1022I don't looks like proper signal, because such kind of differential data transmission bus needs also differential probe. Somewhere in the Net I seen it's possible to make a "math" differential probe if to connect grounds of both channels and measure (A) and (B) wires of RS-485 by two channels of VDS1022I and make math operation on them. But yet I didn't tested it on VDS1022I.


P.S> I got that I had to open "vds1022.ipynb" in a Jupyter notebook and start examples from there. And there is an Error in TTL example: "OverflowError: Python integer 128 out of bounds for int8".
P.P.S> Project owner can not support this project any more: Unfortunately I don't plan on spending time on this project.  (https://github.com/florentbr/OWON-VDS1022/issues/103#issuecomment-2391915318)

[SIBtronics]

yeah, i havent found a fix for this issue yet, my knowledge of python is also very basic. the integer out of bounds error has something to do with pythons numpy v2. in the older v1 numpy that did work, but installing that breaks a whole host of other things. i have managed to make it work sometimes by just removing the +128 in that line (probably the real fix would be to make it a 16 bit int, instead of an 8 bit one, but i havent figured out how to do this yet. the serial decode is also kinda broken in that i have managed to call it, but it also throws an error as far as i can remember, or it doesnt show any data, which i2c does. (see attachement for an example) its all a bit broken, because python sometimes likes to arbitrarily change the syntax for some stuff. i havent figured everything out yet. see also my issue: https://github.com/florentbr/OWON-VDS1022/issues/105

[Merlyn]

Hi,

I'm using the OWON 1022I mainly for audio measurements.
When I set "Return to factory settings" one of the stereo channels is "dancing" left-right to the other which suggests variable phase difference. When I press Autoset two channels overlap perfectly.
What's going on and which is the right way?

[SIBtronics]

autoset probably switches to alternating trigger, where it triggers on one and the other channel seperately. if you then go back it goes to a single channel trigger again, meaning one of your signals is weirdly out of sync with the other.

[Merlyn]

Single is out of sync, alternate in sync.

[SIBtronics]

yeah, id guess its your souce thats the issue, or the scopes connection to it.

[Elmue]

Hello OWON fans!

I have good news for you.
There is a new software for your scope that is much better than what you get from OWON.
And it is open source.
https://netcult.ch/elmue/Oszi-Waveform-Analyzer

The OWON Java application is very primitive. It has several issues.
The worst is that there is no horizontal scrollbar. It is a mess to move the signal if you are zoomed into it.
And if you are at a higher zoom level suddenly parts of the signal disappear.
And if you show a CAP file you cannot even zoom into the signal, nor can you scroll it.
Measuring of exact timing or exact voltages is not provided.
It is a primitive Chinese software that displays a signal, but not much more.


But now you can use Oszi Waveform Analyzer which offers you lots of new features.
You get a high quality user interface with lots of features.
Oszi Waveform Analyzer can import the proprietary and completely undocumented OWON files in 3 formats: BIN, CAP and CSV.
A BIN file contains one capture buffer of 5000 samples.
A CAP file consists of multiple "frames" of only 4000 samples, each transferred over USB one by one.
The original OWON software shows you only one frame at a time when you open a CAP file.

But Oszi Waveform Analyzer combines the frames in one display (obviously with scrollbar).
A vertical red line marks the end of a frame and the begin of the next.
The data in between is lost because of the delay of the USB transfer.



Read the detailed manual so you don't miss the plenty features:

Oszi Waveform Analyzer supports analog and digital channels.
Oszi Waveform Analyzer can zoom the signal horizontally and vertically.
Oszi Waveform Analyzer has menu with the available operations that appears when you right-click into the signal.
Oszi Waveform Analyzer shows signal details in a tooltip, can measure voltages and precise timing and show a measure raster.
Oszi Waveform Analyzer has multiple A/D converters, noise suppression, can apply math operations on signal data, etc.
Oszi Waveform Analyzer has a logic analyzer for SPI bus, I²C bus, CAN Bus, UART (RS232), and more with full decoding.
Oszi Waveform Analyzer can split bidirectional half-duplex traffic on the Data wire into separate Rx and Tx channels.
Oszi Waveform Analyzer allows to decode chip-specific SPI and I²C packets and protocol specific UART packets.
Oszi Waveform Analyzer can edit analog and digital signals with copy and paste.
Oszi Waveform Analyzer stores waveforms in the open-source OSZI file format which applies the highest compression to waveform data.
Oszi Waveform Analyzer is open source and YOU can add new decoders, file formats and oscilloscope models.
Oszi Waveform Analyzer allows you to analyze very specific signals that you cannot even analyze with most expensive commercial products.
Oszi Waveform Analyzer is high quality software, written by a software and hardware developer with 40 years of programming and electronic experience.
Oszi Waveform Analyzer is optimized for maximum speed in every line of it's very clean source code.

Here you see an I2C signal decoded:



Oszi Waveform Analyzer can also transfer oscilloscope captures over USB, TCP or VXI using SCPI commands.
But this is currently not yet implemented for OWON.
You can implement this feature because the OWON SCPI commands are documented and Oszi Waveform Analyzer is open source.

[SIBtronics]

cool software!
mind sharing how to do this in scpi?

[MarktheRFguy]

I recently got a used (but excellent condition) VDS1022I, and have been impressed by its usefulness. It's my lowest bandwidth and sample rate 'scope (I have 8 others - bad case of GAS), but it still helped me repair the oscillator in an old Heathkit ET3100 (and a few other things).

I have a question for the VDS1022 gurus on here though: does the VDS1022(/I) actually do equivalent time sampling, or is it just faked in software? Since the triggering happens in the FPGA (after the ADC), I don't see how it could, unless there's an internal clock in the ADC operating at 1GHz (or more) to offset the sampling clock. I ask this because of the attached image, showing a waveform (the rising edge of the 1kHz probe comp output) captured at 50ns/div, zoomed in to 5ns/div and displayed using dot mode (should show a dot for every sample). It shows dots every 1ns, which is 10 times faster than the waveform can be sampled in real time. A couple of my other 'scopes can do equivalent time sampling (up to 100GSa/s), but they have much more complex triggering circuits and ADC clocking. Is the software just making up 90% of the samples shown in the image, or does the ADC in the VDS1022(/I) have some cool trick up its sleeve?

Thanks - mark.

[TizianoHV]

It shows 1ns steps even in single mode. Probably its just interpolating.
When you zoom in it still gives you 5000 points (I don't know if it's done by the software or the oscilloscope). Maybe some sort of "hack" so that the plot always gets the same number of points to plot?

[runcyclexcski]

Merlyn -- I understand this is an old thread. May I ask what RMS and peak-to-peak noise you are seeing with the VDS1022 at its most sensitive scale (5mV) -- i.e. the internal noise? From the first few posts on this thread, it appears to be about 0.2/0.1 mV, but I may be wrong. I am considering this unit to measure sub 1mV steps at 1-10kHz.