Modbus Monitor

Quantum Bit Solutions

About this app

Learn Modbus the Easy Way - Perfect for Beginners & Hobbyists!

New to Modbus? Modbus Monitor Free makes it simple to connect and communicate with industrial devices. Whether you're a student, hobbyist, or field technician, start learning Modbus protocols in minutes with our intuitive form-based interface!

🎓 Beginner-Friendly Interface:
Simple fill-in-the-form design - no confusing codes!
Select function from dropdown menu (Read/Write Coils, Registers)
Enter device address (1-247) and register number
Big "Read" and "Write" buttons - one tap to communicate
See results instantly in clear text display

📝 Easy 3-Step Process:
Select Function - Choose from dropdown (Read Coils, Read Holding Registers, etc.)
Enter Details - Device address, register number, and quantity
Tap Read or Write - Get results immediately!
No Complex Address Formats!
Unlike other tools, you don't need to memorize cryptic codes. Just fill in simple fields:

Device address: 1-247
Register number: The register you want to read/write
Quantity: How many registers to read
Function: Selected from easy dropdown menu

📱 Multiple Connection Options:
✓ Modbus TCP - Connect over WiFi/Ethernet
✓ Bluetooth Classic (SPP) - Wireless serial connections
✓ Bluetooth Low Energy (BLE) - Modern wireless devices
✓ USB Serial Ports - Direct cable connections (FTDI, Prolific, CH34x, Silabs)

💡 Quick Example:
Want to read register 1 from device 1?

Device address: 1
Function: "FC03: Read Holding Registers"
Register: 1
Quantity: 1
Tap "Read" → Done!
Want to read 10 registers at once? Just change Quantity to 10!

🔧 Perfect For:
Students learning industrial automation
Hobbyists experimenting with PLCs and sensors
Technicians doing quick device diagnostics
Arduino/Raspberry Pi projects with Modbus
Anyone testing Modbus communication without coding

🎯 What You Can Do:
Test PLC communication before programming
Troubleshoot sensor connections
Learn Modbus protocol hands-on
Monitor temperature, pressure, and control values
Experiment with industrial IoT devices
Control relays and read sensor data

📶 Supported Hardware:
PLCs (Programmable Logic Controllers)
Industrial sensors and actuators
Arduino with Modbus capability
Raspberry Pi with Modbus
Energy meters and inverters
HVAC control systems
Variable frequency drives (VFDs)
Any Modbus TCP or RTU compatible device

✨ Key Features:
Dropdown function selector (no memorizing codes!)
Separate fields for device, register, quantity, and value
Live 6-digit address preview (for reference)
Large, readable response display
Beginner-friendly helper tips built-in
Clean, modern Material Design interface
No ads, no tracking, no subscriptions

🆓 100% Free - No Hidden Costs!
Try it risk-free! Once you're comfortable with Modbus basics, upgrade to Modbus Monitor Advanced (separate app) for professional features like data logging, sensor server, cloud integration, and automation.

📚 Learning Resources:
Built-in helper tips guide you through each step
Video tutorials on our YouTube channel
Responsive email support
Active user community

Need Help?
📧 Email: [e-mail]
🌐 Website: ModbusMonitor.com
📺 Video Tutorials: Search "Modbus Monitor" on YouTube

Start your Modbus journey today with the easiest Modbus app available!

Ratings and reviews

It's a neat idea, but only works about halfway, at best. I could only get it to read integers. floats read as ints, so that's basically non-functional. I could not get it to write anything at all. when reading back the Tx/Rx string, it doesn't even show transmitting the Write value. Awkward overall and minimally useful. good proof of concept to continue to build.

Difficult App, very little documentation. This is all the help for using the API and there are numerous technical errors. No examples of reading or writing to coils, and no clear output of the send message and reply: "The Modbus addresses are polled using the 6-digit address scheme “Xnnnnnn”. The first digit (“X” ) is the standard Modbus address scheme followed by 5-digit Modbus". I did eventually manage to work out how to use the app myself, but it was not easy. Good documentation required.

Thanks.Very useful for an automation engineer.