Modbus RTU Tester

Modbus RTU Tester is a mobile diagnostic tool designed for engineers and technicians to validate RS485/Modbus devices directly in the field.

With a USB‑RS485 adapter, you can configure communication parameters and perform single or continuous reads, write operations, quick device scans, and bus monitoring—right from your phone.

Key Features

Read & Write Operations

Read registers and perform Modbus writes (0x05/0x06/0x0F/0x10) with automatic read‑back verification.

Single & Continuous Reads

Use common Modbus function codes and verify device responses in real time.

Quick Scan

Scan a defined ID range to discover responsive devices, with first‑value preview.

Bus Monitor

Inspect TX/RX raw data and communication history (including write ACK/verify logs) to trace bus activity and issues.

Flexible Communication Settings

Configure Port, Baud Rate, Parity, Timeout, Latency, and Retries.

Advanced parameters are available in Pro.

Operation Modes

Demo mode for offline demonstrations; Live mode for real hardware connections.

Free vs Pro

Free: Basic read operations and standard communication settings.

Pro: Unlocks continuous reads, quick scan, advanced communication controls, and extended protocol testing (including write verification).

Use Cases

Factory and on‑site maintenance

Equipment commissioning and acceptance testing

RS485/Modbus troubleshooting and parameter tuning

Privacy & Data

All connection settings, logs, and history remain on the device.

No data is uploaded or shared externally.

In‑app purchases are handled securely through Google Play.

Requirements

Android 7.0 (API 24) or newer (targetSdk 36).

Device with USB Host/OTG support and a USB‑RS485 adapter

(based on usb‑serial‑for‑android).

Core RS485 functionality works via USB without requiring Google Play services.

Supports connection testing for common inverter communication protocols (Pro).