Free Modbus TCP & RTU Client, Scanner & Logger
Download the fastest free Modbus TCP, RTU and ASCII Client and Scanner. The ultimate Modbus Client, Scanner, and Logger in one intuitive interface. Visualize data and debug problems instantly.
By Crabby - Made for Windows, macOS and Linux
Unlimited Devices
Lightning Speed
Modbus TCP & RTU Client & Scanner Features
A complete Modbus TCP, RTU and ASCII Client, Scanner, and Logger with powerful features for industrial automation professionals
Modbus TCP Scanner
Scan entire networks and individual devices to discover Modbus TCP endpoints automatically. Our scanner finds devices across IP ranges and identifies their unit IDs instantly.
- Scan IP ranges & full networks
- Scan device IDs 1-247
- Extract vendor & product info
Modbus TCP & RTU Client
A full-featured Modbus client that monitors multiple devices simultaneously with configurable polling intervals - over Modbus TCP on the network, or Modbus RTU and Modbus ASCII on a serial port. Track changes in real-time with visual highlighting.
- Multi-session monitoring
- 100ms to 60s polling intervals
- Pause/resume sessions
- Unit-ID scan on a serial port
Modbus Logger
Powerful Modbus Logger that automatically records register data to files in multiple formats. Perfect for long-term data collection and compliance.
- CSV, JSON, Tab-Delimited formats
- Configurable log rotation policies
- Multiple concurrent loggers
Per-Register Configuration
Advanced per-register settings with scaling, custom formulas, custom units, and multiple data formats for specialized measurements.
- Linear scaling with offset
- Custom formulas per register
- Combine registers into derived values
- 30+ unit presets + custom units
- 8 data format types (Float32, Int32, etc.)
Protocol Logging
Inspect raw Modbus traffic with TX/RX logging. Perfect for debugging and analysis.
- Raw byte inspection
- Hex display with timestamps
- Error tracking
High Performance
Built with Rust for blazing-fast performance and minimal resource usage.
- Rust backend for speed
- Low memory footprint
- Responsive UI
Learn Modbus
Practical guides to scanning, addressing and getting data out of Modbus TCP devices.
Getting Started with Modbus Connect
Install the app, add a device and take your first reading.
How to Scan a Modbus Network
Find every Modbus TCP device on a subnet, in quiet or fast mode.
Modbus Exception Codes Explained
What each exception code means and what to check when a device returns one.
Versioning a Modbus Register Map
Keep register maps readable when the PLC program changes.
Block Transfers and Polling Efficiency
Why fewer, larger reads cut protocol overhead on slow devices.
Modbus TCP vs PROFINET, EtherNet/IP and OPC UA
What each protocol is for, and when Modbus TCP is enough.
How This Free Modbus Tool Works
Get started in minutes—scan, connect, and diagnose problems instantly
Discover Devices
Run the device scanner to automatically find all Modbus devices on your network. Add them to your device list with custom names.
Start Monitoring
Select a device, configure register type and address range, then start monitoring. Track multiple devices simultaneously.
Analyze & Save
View real-time data, create charts, and save your workspace. Export data for documentation and reporting.
Free Modbus TCP & RTU Client Pricing
Download the free Modbus tool now. Full access during development with single license for production use.
Single License
Pricing TBD for v1.0 release
- All current features included
- Unlimited devices & sessions
- Data logging, real-time charting and saved workspaces
- Windows 7/8/10/11 (64-bit), macOS 10.15+ (Apple Silicon & Intel) and Linux support
Download the Free Modbus TCP & RTU Client Today
Join automation professionals using this free Modbus tool to scan, log, and diagnose problems instantly
Download NowContact Modbus Connect
Have questions or feedback? I'd love to hear from you.
crabby@modbusconnect.com