OWON VDS1022I Quick Teardown (versus the Hantek 6022be)

[Gyro]

As far as I can see, the SIM3U156 VREF is used as a common mode reference node for the top side SGM8292, which is effectively being used as an I/V converter for the offset adjustments.

They've been careful to take the SGM8292 supply rails from the analogue regulators at the front of the board.

Actually, they may well be using the SIM3U156 VREF indirectly as a calibration source for the ADC... As it is the reference for the IDACs, they can feed a known offset voltage to the LMH6551s and read back the resulting ADC reading. That will allow closed loop calibration of the ADC (and LMH6551 offsets).

I can't see how they can go past that though (to the AD603 gain calibrations) other than to null their offsets by assuming 0V inputs (probes disconnected). There are relay clicks during self-cal, I don't know how many relays there are under the shield, but there must be at least two per channel, one for AC/DC coupling and one for the higher voltage ranges, maybe there's another shorting one.

[camomille]

I think it's the same model (NEC) as in the 4 channels.

[Gyro]

Ah, only one per channel on that one, presumably AC/DC coupling. It's not the same circuit as the VDS1022 though - it's missing the trimmer caps near the rear of the shields.

At some point, curiosity is going to persuade me to desolder the shield but I'm trying to resist!

[camomille]

Surely this model double coils latch.

[Gyro]

Yes, it is a double pole changeover (DPDT), the two contacts are mechanically linked. It uses two coils (bistable) so is stable in both states. It minimises current draw and power dissipation. A good thing to do when USB powered.

[camomille]

My contribution to enlighten this subject

[indman]

I noticed another problem in the mathematical channel that is present in all versions of the shell, including 1.0.30. The selected range value (for example,5V) is not saved when the program is reloaded. There is also no preservation of this meaning if you remove the bird from the function of mathematics and put it again.

Can you confirm or deny this problem?

[Gyro]

My contribution to enlighten this subject

Nice reverse engineering, thanks. 

I'm away from my unit for a few days.

[jemangedeslolos]

Hello,

I bought a VDS3102 that I haven't received yet.
Do you know if the software is the same between the 1022 and the 3102 ?
I can't download the software from Owon, I don't know why.
It seems that most of their links are dead.

It is nice to be able to change the channel color. I will look more deeply when I received to scope.

[Gyro]

I'm not sure why you're having trouble downloading the s/w, it's on their support page (I just tried it) ... https://www.owon.com.hk/support_PC_Software_list3

The best bet is normally to install the version that comes on the CD and then check if the site version is a later Rev.

No, the s/w is different between the two (although I'm sure they are closely related) - you can normally delve deeper by unzipping the installer exe file.


P.S. You can find the user manual in the support pages too.

[camomille]

A small gift for the Christmas holidays

[Gyro]

Hey Camomille, that's very useful - thank you! 

It's the sort of thing I kept meaning to do, wished I had, but never got around to! I wondered how they implemented things like the multi Input/output.

Now to work out why my earlier version PCB uses a switcher for the -2.5V rather than an LM337 - they must have had some reason for changing it.

I will try to get around to lifting the shield and taking some photos sometime over Christmas.

[jemangedeslolos]

It seems that I tried only when the links were dead 
It is working great now, thank you 

[camomille]

Hello Chris

It is between diagram and synoptics to understand the operation, I deliberately forgot the decoupling capacitors.
What I find interesting is the hc595 which serves as a serial / parallel interface between the cpu and the inputs (6 lines).
One might think that one of these lines isolates the inputs and authorizes a reference voltage for the auto calibration.
I also highlighted the FPGA series programming.
My model does not have circuits with a red cross.

Alain

[Gyro]

It seems that I tried only when the links were dead 
It is working great now, thank you 

Glad to hear it. 

Thinking overnight, there may not actually be many differences between the VDS1022 s/w and the 3102. After all, they both have the same user interface. Irrc, the 3102 uses USB2 High speed rather than full speed (the reason it doesn't have a galvanic isolation option) so there will be differences in the device driver etc, and of course the FPGA firmware file will be different.

You may want to download the latest VDS1022 and the latest VDS1032 s/w, unzip the installer exe files to two separate folder trees (7zip works) and look for commonalities.

[Gyro]

Hello Chris

It is between diagram and synoptics to understand the operation, I deliberately forgot the decoupling capacitors.
What I find interesting is the hc595 which serves as a serial / parallel interface between the cpu and the inputs (6 lines).
One might think that one of these lines isolates the inputs and authorizes a reference voltage for the auto calibration.
I also highlighted the FPGA series programming.
My model does not have circuits with a red cross.

Alain

Hi Alain,

It's fine - just what is needed to know what is going on.    It's useful to know which regulator is powering what. I had worked out that the Probe cal output was driven directly from 5V USB - it is a useful indication of excessive voltage drop on the cable before any other functionality is affected.

Mine still has the BA7046 sync separator, yes it's probable that they've moved the functionality into the FPGA, it's a less used function these days anyway.

Regarding the HC595 outputs - it will be interesting to know what is happening under the shield. I think we can be sure this splits down to 3 control lines per channel, I doubt there is any binary decode going on under the shield, so I think they will be switching 3 discrete items. One will clearly be the AC/DC coupling relay. I wouldn't be surprised if another one is switching an attenuator for the higher voltage ranges. As for the third, yes maybe a reference select, or maybe another attenuator? I will try to find out.

Chris

[camomille]

BA7046 is only NTSC.

small precision, no power goes under the shield, just the ground.

My opinion :
the 6 wires must directly attack 2 bistable relays per channel (AC / DC / GND) and (1V / 0.1V / 0.01V).

It is only a suggestion.

Alain

[Gyro]

small precision, no power goes under the shield, just the ground.

Ah, that's interesting, I was thinking there might be another gain stage in there for low ranges. Also clamping to the rails.


P.S. I don't think the GND position is needed on the input coupling relay - the S/W takes the trace to a flat line when GND is selected.

Chris

[Mikle_JV]

Hi guys!
Thank you for your work. I installed the package on a Raspberry pi 4. It works!!
Here is my instruction :
( It certainly looks like dancing with a tambourine.    But the Java code gives me the fear, pain and hatred. I hope that in the future it will be corrected by knowledgeable people. )
I installed on a clean system downloaded from the original site "Raspbian Buster with desktop". 
First, the standard:

Code: [Select]

sudo apt-get update
sudo apt-get upgrade
Then install Java and the necessary libraries:

Code: [Select]

sudo apt-get install openjdk-8-jre
sudo apt-get install libusb-1.0-0-dev
sudo apt-get install libusb-dev
sudo apt-get install libusb-java-lib
sudo apt-get install librxtx-java
Install OWON software on two options to choose from:
1)

Code: [Select]

git clone https://github.com/florentbr/OWON-VDS1022.git2)

Code: [Select]

wget https://github.com/florentbr/OWON-VDS1022/archive/master.zip
unzip /home/pi/master.zip

Code: [Select]

cd /home/pi/OWON-VDS1022-master (If you used Git the folder will be OWON-VDS1022 , but I used Wget)
Now we knock on the tambourines:

Code: [Select]

mkdir lib/linux/armhf
cp /usr/lib/arm-linux-gnueabihf/libusb.so /home/pi/OWON-VDS1022-master/lib/linux/armhf/
cp /usr/lib/libusbJava.so.0.8 OWON-VDS1022-master/lib/linux/armhf
cp /usr/lib/libusb.so  /home/pi/OWON-VDS1022-master/lib/linux/armhf
cp /usr/lib/jni/librxtxSerial-2.2pre1.so /home/pi/OWON-VDS1022-master/lib/linux/armhf   
Edit the installation script in two places:

Code: [Select]

nano /home/pi/OWON-VDS1022-master/install-linux.sh

main () {

        local arch
        case "$(uname -m)" in
                x86_64|amd64) arch=x86_64  ;;
                i?86)         arch=i386    ;;
                arm*)         arch=armhf   ;; #!!!!!!!!!!!!
                *)            raise "Architecture not supported: $(uname -m)"  ;;
        esac


   
build-deb () {
        local arch=$1

#       PK_ARCH=${arch/x86_64/amd64}
        PK_ARCH=$arch   #!!!!!!!!!!!!!!!

Save and exit
Ctrl-X      

Next, change the attribute and run:      

Code: [Select]

sudo chmod +x /home/pi/OWON-VDS1022-master/install-linux.sh
sudo /home/pi/OWON-VDS1022-master/install-linux.sh
After installation we make symbolic links:

Code: [Select]

cd /usr/lib/owon-vds-tiny
sudo ln -s librxtxSerial-2.2pre1.so librxtxSerial.so
sudo ln -s libusbJava.so.0.8 libusbJava.so
Everything is ready now you can run

[camomille]

Hi all,

Before this new year, I decided to open the sardine box (shield).

in 2020 the complete scheme.

I wish everyone a happy New Year.

Alain 

[Gyro]

Damn, you beat me to it - I was going to make it a New Year present to you!

From an initial look, U2 and U43, the LETEX L1210 parts appear to be opto relays for the AC/DC coupling switch, something like PhotoMOS. These bypass the AC input coupling capacitors, C48 and C20. The 330R resistors, R4 and R97 look right for driving an internal LED.

The relays then must be for switching a high level resistive||capacitive attenuator for the higher volts/div ranges, with capacitive compensation being adjustable by the two trimmer caps.

I can't find any web reference for either LETEX or LETEX L1210, so it is a part that it would be best not to blow up!

Thanks for doing this Alain, and a Happy New Year to you. 

Chris

[Gyro]

Hi guys!
Thank you for your work. I installed the package on a Raspberry pi 4. It works!!
Here is my instruction :
( It certainly looks like dancing with a tambourine.    But the Java code gives me the fear, pain and hatred. I hope that in the future it will be corrected by knowledgeable people. )
I installed on a clean system downloaded from the original site "Raspbian Buster with desktop". 
First, the standard:

Code: [Select]

sudo apt-get update
sudo apt-get upgrade
Then install Java and the necessary libraries:

Code: [Select]

sudo apt-get install openjdk-8-jre
sudo apt-get install libusb-1.0-0-dev
sudo apt-get install libusb-dev
sudo apt-get install libusb-java-lib
sudo apt-get install librxtx-java
Install OWON software on two options to choose from:
1)

Code: [Select]

git clone https://github.com/florentbr/OWON-VDS1022.git2)

Code: [Select]

wget https://github.com/florentbr/OWON-VDS1022/archive/master.zip
unzip /home/pi/master.zip

Code: [Select]

cd /home/pi/OWON-VDS1022-master (If you used Git the folder will be OWON-VDS1022 , but I used Wget)
Now we knock on the tambourines:

Code: [Select]

mkdir lib/linux/armhf
cp /usr/lib/arm-linux-gnueabihf/libusb.so /home/pi/OWON-VDS1022-master/lib/linux/armhf/
cp /usr/lib/libusbJava.so.0.8 OWON-VDS1022-master/lib/linux/armhf
cp /usr/lib/libusb.so  /home/pi/OWON-VDS1022-master/lib/linux/armhf
cp /usr/lib/jni/librxtxSerial-2.2pre1.so /home/pi/OWON-VDS1022-master/lib/linux/armhf   
Edit the installation script in two places:

Code: [Select]

nano /home/pi/OWON-VDS1022-master/install-linux.sh

main () {

        local arch
        case "$(uname -m)" in
                x86_64|amd64) arch=x86_64  ;;
                i?86)         arch=i386    ;;
                arm*)         arch=armhf   ;; #!!!!!!!!!!!!
                *)            raise "Architecture not supported: $(uname -m)"  ;;
        esac


   
build-deb () {
        local arch=$1

#       PK_ARCH=${arch/x86_64/amd64}
        PK_ARCH=$arch   #!!!!!!!!!!!!!!!

Save and exit
Ctrl-X      

Next, change the attribute and run:      

Code: [Select]

sudo chmod +x /home/pi/OWON-VDS1022-master/install-linux.sh
sudo /home/pi/OWON-VDS1022-master/install-linux.sh
After installation we make symbolic links:

Code: [Select]

cd /usr/lib/owon-vds-tiny
sudo ln -s librxtxSerial-2.2pre1.so librxtxSerial.so
sudo ln -s libusbJava.so.0.8 libusbJava.so
Everything is ready now you can run

Hi Mikle_JV,

Welcome to the forum. 

Excellent work, I know that several people have ambitions for turning the scope into a truly portable device, and the Pi seems the best platform for doing this. Thanks for detailing so fully! 

Chris

[camomille]

Hello Chris,

It is not LETEX L1210 but LT210 (Photo DMOS-FET Relay) and it is good to use for short circuit the AC / DC input capacitor.

search  LT210.pdf

The NEXEM UD2 5SNU double inverter bistable relay simply switches a divider by 25 used in the 5/2/1 / 0.5 Volts positions.

Alain

[Gyro]

Ah, that makes more sense, thanks, got it (I had too many disturbing latex hits before )! It looks man enough for the job and decent isolation. Here's the link for anyone else interested... http://www.letex.com.tw/dow.php?type=pdf&file=.%2Fupload%2Fproduct%2FLT210%2Ffile1.pdf&serial=LT210

Divide by 25 then - you're ahead of me again!

Thanks,
Chris


P.S. The single coil bistable relay explains why there are 3 control lines (total) going to each channel.

[camomille]

I discovered the division by 25 while having fun making this document.

I am waiting for the components to realize a full scale voltage tester 50v to 500mV and finalized.