A modern, web-based control interface for the OWON OEL8511 Electronic Load using the Web Serial API. Control your electronic load directly from your browser with real-time monitoring, data logging, and battery testing capabilities.

• Constant Current (CC) - Precision current sinking
• Constant Voltage (CV) - Voltage regulation mode
• Constant Resistance (CR) - Electronic resistance simulation
• Constant Power (CP) - Power dissipation control
• • Dynamic mode - Switch between two preset current levels
• Battery Test - Automated discharge testing with capacity measurement

• Live voltage, current, and power readings
• Real-time graphing with Chart.js
• Configurable update rate (100-5000ms)
• Min/Max statistics tracking
• Capacity and energy measurements (mAh, Wh)
• Duration tracking with HH:MM:SS timer

• Adjustable current range (AUTO/LOW/HIGH)
• Slew rate control for smooth transitions
• Over-voltage protection (OVP)
• Over-current protection (OCP)
• Over-power protection (OPP)
• Short circuit protection
• Remote sensing capability
• Immediate device updates on value changes

• Multiple battery chemistry presets (Li-ion, LiPo, LiFePO4, NiMH, NiCd, Lead Acid)
• Customizable discharge current
• Voltage cutoff with auto-stop
• Real-time State of Charge (SOC) calculation
• Discharge curve graphing
• Comprehensive test data logging

• CSV export of all measurements
• PNG snapshot of graphs
• Test reports with summary statistics

• Dark theme optimized for long sessions
• Material Design inspired interface
• Responsive layout
• Intuitive dial visualizations
• Color-coded readings
• Status indicators

The Web Serial API is required to communicate with the device. Supported browsers:

No installation required! This is a standalone HTML file.

1. Download owon_web_complete.html
2. Double-click to open in your browser, or
3. Host on a web server for HTTPS access

1. Open the file in Chrome, Edge, or Opera
2. Connect your OWON OEL8511 via USB
3. Click "🔌 Connect" button
4. Select your device from the port list (usually "USB-SERIAL CH340" or similar)
5. Device connects automatically and reads current settings

The application automatically configures:

• Baud Rate: 115200
• Data Bits: 8
• Stop Bits: 1
• Parity: None
• Flow Control: None

Sidebar → Click CC/CV/CR/CP/Dynamic button
Device automatically switches mode
Settings populate from device

Enter value in input field
Press Enter or Tab
Command immediately sent to device
Dial updates to show setting

Click "🟢 INPUT ON" button
Load activates
Real-time monitoring begins
Graph starts recording

Watch live readings update
View real-time graph
Statistics tracked automatically
Export data when complete

Use Case: Discharge testing, LED testing, current source simulation

1. Select Load > CC from sidebar
2. Set Current: Enter desired current (0-20A)
3. Configure Settings:
   • Current Range: AUTO/LOW/HIGH
   • Slew Rate: Transition speed (A/μs)
   • Current Limit: Maximum current
   • Voltage On Level: Turn-on threshold
4. Enable Protections:
   • OVP: Over-voltage protection
   • OCP: Over-current protection
   • OPP: Over-power protection
5. Click INPUT ON
6. Monitor load in real-time

Use Case: Battery charging simulation, voltage regulation testing

1. Select Load > CV from sidebar
2. Set Voltage: Enter desired voltage (0-150V)
3. Configure Settings:
   • Voltage Range: AUTO/LOW/HIGH
   • Current Limit: Maximum current draw
   • Remote Sensing: Enable for accurate voltage
4. Click INPUT ON

Use Case: Resistive load simulation, heater testing

1. Select Load > CR from sidebar
2. Set Resistance: Enter desired resistance (Ω)
3. Configure Settings:
   • Current Limit: Safety limit
   • Power Limit: Maximum power
4. Click INPUT ON

Use Case: Power supply testing, thermal testing

1. Select Load > CP from sidebar
2. Set Power: Enter desired power (0-200W)
3. Configure Settings:
   • Voltage Limit: Maximum voltage
   • Current Limit: Maximum current
   • Slew Rate: Power transition speed
4. Click INPUT ON

Complete discharge capacity test with automatic cutoff

1. Click 🔋 Battery in sidebar
2. Configure Battery:
   • Battery Type: Select chemistry (Li-ion, LiPo, etc.)
   • Cell Count: Number of cells in series
   • Rated Capacity: Expected capacity (mAh)
3. Set Test Parameters:
   • Discharge Current: Test current (A)
   • Cut-off Voltage: End voltage (V)
   • Auto Stop: Enable automatic termination
4. Connect Battery to load terminals

1. Click ▶️ Start Test
   • Device switches to CC mode
   • Discharge current applied
   • Monitoring begins
2. Watch Progress:
   • SOC percentage with progress bar
   • Discharged capacity (mAh)
   • Energy delivered (Wh)
   • Average voltage
   • Test duration
3. Test Completes:
   • Auto-stops at cutoff voltage
   • Final statistics displayed
   • Data ready for export

Battery Test Completed!

Cutoff voltage reached: 3.00V
Capacity: 2450 mAh
Energy: 9.05 Wh
Duration: 01:13:25

Click 💾 Save Data to export:

Time,Voltage,Current,Power,Capacity
0.0,12.345,2.000,24.690,0
0.5,12.340,2.000,24.680,0.3
1.0,12.335,2.000,24.670,0.5
...

Click 📸 Snapshot to save:

• PNG image of current graph
• Filename includes mode and timestamp
• Example: owon_CC_graph_2025-11-26T14-30-00.png

Control how often measurements are taken:

Settings Panel → Update Rate
Range: 100-5000ms
Default: 500ms (2 samples/second)

Recommendations:

• 100-250ms: Fast transients, dynamic testing
• 500ms: Normal operation (default)
• 1000-2000ms: Long duration tests, reduced data
• 5000ms: Multi-hour tests, minimal logging

Control how many data points to keep in memory:

Settings Panel → Buffer Size
Range: 100-10000 points
Default: 1000 points

Recommendations:

• 100-500: Short tests, quick response
• 1000: Normal operation (default)
• 5000-10000: Long tests with high update rate

Customize what's displayed:

• ☑️ Voltage - Blue trace
• ☑️ Current - Green trace
• ☑️ Power - Red trace
• ☐ Capacity - Purple trace (optional)

Problem: No serial port appears in connection dialog

Solutions:

1. Check USB cable connection
2. Install CH340 driver if needed (Windows)
3. Try different USB port
4. Restart browser
5. Check device power

Problem: Error when clicking Connect button

Solutions:

1. Close other applications using the port
2. Disconnect and reconnect device
3. Refresh browser page
4. Check serial settings match device

Problem: Voltage/current showing zeros or wrong values

Solutions:

1. Check console for validation warnings
2. Ensure INPUT is enabled on device
3. Verify SCPI commands supported
4. Check device firmware version
5. Try lower update rate

Problem: Configuration fields remain empty

Solutions:

1. Wait 5 seconds for periodic update
2. Check console for "not supported" messages
3. Ensure device in correct mode
4. Try manual entry
5. Device may not support query command

Problem: Cannot enable/disable short circuit

Solutions:

1. Check console for error messages
2. Command may not be supported by device
3. Try via device front panel
4. Check firmware version
5. Feature may require specific hardware

Problem: Browser doesn't support Web Serial API

Solutions:

1. Use Chrome 89+, Edge 89+, or Opera 75+
2. Enable chrome://flags/#enable-experimental-web-platform-features
3. Use HTTPS connection (not http://)
4. Try different browser

Problem: CSV or PNG not downloading

Solutions:

1. Check browser download permissions
2. Clear browser cache
3. Try different download location
4. Check disk space
5. Disable popup blocker

⚠️ Always follow proper safety procedures:

1. Power Limits: Never exceed device ratings (150V, 20A, 200W)
2. Heat Management: Ensure adequate cooling during high-power operation
3. Battery Testing: Monitor temperature, never leave unattended
4. Polarity: Verify correct polarity before connection
5. Fusing: Use appropriate fuses in your circuit
6. Isolation: Ensure proper electrical isolation

✅ For Reliable Testing:

1. Warm Up: Allow 10 minutes warm-up before precision testing
2. Calibration: Regularly verify readings with known references
3. Cable Quality: Use short, heavy gauge cables to minimize resistance
4. Ventilation: Maintain good airflow around device
5. Data Backup: Export data regularly during long tests
6. Range Selection: Use appropriate current range for accuracy
7. Remote Sensing: Enable for accurate voltage measurements
8. Update Rate: Balance between resolution and data volume

This project is licensed under the MIT License - see the LICENSE file for details.

MIT License

Copyright (c) 2025 Jobit Joseph

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

Jobit Joseph

• GitHub: @jobitjoseph
• YouTube: Electronics Channel
• PayPal: Support Development

• OWON - For the OEL8511 Electronic Load
• Chart.js - For the excellent graphing library
• Web Serial API - For enabling browser-to-device communication
• Community - For feedback, testing, and suggestions

• Version: 1.0.0
• Status: Active Development
• Last Updated: November 2025
• Stability: Stable

If you find this project useful, please consider giving it a ⭐ on GitHub!

Made with ❤️ for the electronics community