OWON Scope Web
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Your OWON oscilloscope, in the browser

Live view, measurements, cursors, recording and playback for OWON scopes connected over USB.

Scope not listed or not connecting? Open the setup guide →

No recording
ChannelVppMaxMinMeanRMSFreqPeriodDuty
Screenshot from the oscilloscope
Save

Keyboard shortcuts

Space
Live on / off
C
Capture one frame
R
Start / stop recording
P
Play / pause recording
← →
Previous / next frame
K
Cursors
F
Full screen
Wheel
Zoom time (Shift: volts)
Drag
Pan
Double-click
Reset zoom

Connect your OWON oscilloscope

  1. Turn the scope on and connect it with a data USB cable to the square USB-B port on the back (the front USB-A port is only for memory sticks). Some cheap cables only carry power: if nothing shows up, try another one.
  2. Use Chrome, Edge, Opera or Brave on a computer. Firefox and Safari can't talk to USB devices (see “Other browsers”).
  3. Do the one-time setup for your system below, then click Connect USB.
  4. In the list, pick your scope. OWON scopes rarely say “OWON”: look for LILLIPUT S3C2410A SPQ SYSTEM, System MCU, OWON or similar (Lilliput is the company that makes OWON scopes). Then click Connect.

Linux only lets the administrator open USB devices. Install this rule once (it also stops Linux from treating older OWON scopes as a serial cable):

curl -fsSLO https://fmesasc.github.io/owon-scope-web/99-owon.rules
sudo cp 99-owon.rules /etc/udev/rules.d/
sudo udevadm control --reload && sudo udevadm trigger

Then unplug the scope and plug it back in. If Chrome was open while you did this, close it completely and open it again.

Windows gives the scope to OWON's own driver (or to no driver at all), and the browser can't use it like that. Switch it to Microsoft's generic WinUSB driver once:

  1. Download Zadig and run it (no installation needed).
  2. Menu Options → List All Devices.
  3. In the drop-down, choose your scope (LILLIPUT…, System MCU or OWON…; USB ID 5345 1234).
  4. On the right, select WinUSB and click Replace Driver (or Install Driver).
  5. Unplug and plug the scope back in, reload this page and click Connect USB.

OWON's Windows program needs its original driver. To use it again, open Device Manager, right-click the scope → Update driver → pick OWON's driver, or uninstall the device and reconnect it.

No setup is usually needed: open this page in Chrome or Edge and click Connect USB. If the scope doesn't appear, unplug it, plug it back in and try another cable or port (avoid unpowered hubs).

Android: Chrome supports USB. Connect the scope with a USB-OTG adapter (USB-C to USB-A, then the scope's cable) and click Connect USB. Not all phones power the bus well enough; a powered OTG hub helps.

ChromeOS: works like a computer with Chrome. No setup needed.

iPhone and iPad don't allow web pages to use USB devices.

Firefox, Safari and browsers on iPhone/iPad don't support WebUSB. Use the local app instead: it talks to the scope and serves this same page at http://localhost:8642, which works in any browser (and from your phone, with --host 0.0.0.0).

pipx install git+https://github.com/fmesasc/owon-scope-web
owon-scope-web

Needs Python 3.9+ and libusb. Full instructions on GitHub.

Troubleshooting

The list is empty
The computer doesn't see the scope: check it is on, try another cable (data, not charge-only) and another USB port, and make sure you used the port on the back. On Linux, lsusb should show 5345:1234.
The scope appears several times in the list
Old entries from earlier connections. Close the browser completely, unplug and replug the scope, and try again.
“Could not claim the USB interface”
Another program or browser tab is using the scope (OWON's software, the owon-scope-web local app, another tab of this page). Close it. On Linux, install the rule above; on Windows, switch the driver with Zadig.
“Access denied” / “Security error”
On Linux, the rule above isn't installed yet, or the scope wasn't replugged after installing it.
“The scope stopped answering”
Unplug and plug the scope back in, then click Connect USB again. If it happens often, try another cable or port.
It connects but says it doesn't speak a known protocol
Your model may use a protocol this app doesn't know yet. Open an issue with the model name: support for more models is added from those reports.