Modbus Monitor

Quantum Bit Solutions

About this app

Modbus Monitor Free is a fast, simple Modbus TCP/RTU tester for Android.
Connect to PLCs, sensors, and industrial devices in seconds — no coding required.

Easy enough for beginners. Powerful enough for real-world testing.

✔ Connect instantly via Wi-Fi, Bluetooth, or USB
✔ Read and write coils and registers in seconds
✔ Simple form-based setup with clear register addressing
✔ Clean, form-based interface — just enter values and go

Simple 3-step workflow:

1. Select function (FC01, FC02, FC03, FC04, FC05, FC06, FC15, FC16)
2. Enter device address and register
3. Tap Read or Write

Connect wired or wireless:

- Modbus TCP (Wi-Fi / Ethernet)
- Bluetooth Classic (SPP)
- Bluetooth Low Energy (BLE)
- USB Serial (FTDI, Prolific, CH34x, CP21xx, CDC)

Perfect for:

- PLC testing and troubleshooting
- Sensor and device diagnostics
- Industrial automation learning
- Arduino / Raspberry Pi Modbus projects
- Field engineers and technicians

What you can do:

- Test communication before programming
- Read live values from devices
- Write registers and control outputs
- Validate Modbus configurations quickly

Key features:

- Function code dropdown (no memorizing required)
- Separate fields for device, register, quantity, and value
- Real-time response display
- 6-digit address preview
- Clean, lightweight interface

Need continuous monitoring? Try Modbus Monitor Advanced:

- Monitor up to three communication channels simultaneously
- Data logging & CSV export
- Advanced data conversion
- Reusable monitoring configurations
- Automation and advanced monitoring tools
- Pre-built Modbus device maps available for energy meters, power meters, PLCs, and more

Start testing your Modbus devices in seconds.

📚 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 testing Modbus devices today with a simple, practical Android Modbus tool.

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.

Problems are on the begining. I cant change ip number, it is still the same after change to different

What’s new

- Added Copy Button
- Comply to release policies
- Better Serial Port Configuration using single dialog
- Added Scan Button
- Crash Improvements