Modbus Poll

Modbus Poll is a fast, modern Modbus client and server simulator built for engineers, technicians, and developers working with PLCs, inverters, energy meters, HMIs, and industrial sensors. It gives you everything you need to test, debug, and verify Modbus devices — all in a clean, focused interface designed for macOS.

KEY FEATURES

• Dual transport — connect over Serial RTU (USB-to-RS485 adapters) or Modbus TCP/IP. Switch between modes with a single click.

• Full function code support — read coils (FC01), discrete inputs (FC02), holding registers (FC03), input registers (FC04), and write coils (FC05), single registers (FC06), multiple coils (FC15), or multiple registers (FC16).

• Real-time polling — set your own poll interval and watch values update live. Read Once for ad-hoc checks, or Start Poll for continuous monitoring.

• Multiple data views — display register values as Decimal, Hexadecimal, Binary, or 32-bit Float on the fly. Perfect for decoding sensor data or verifying bit-packed status registers.

• Live TX / RX / ERR counters — instantly see whether your device is responding, and how many errors are occurring. Essential for diagnosing flaky wiring or address mismatches.

• Built-in TCP Server Simulator — run a Modbus TCP slave directly from the app. Respond to FC01–FC16 requests from any Modbus master on your network. No hardware required.

• Random Data Generator — automatically randomize holding registers, input registers, coils, or discrete inputs on a configurable interval (250 ms to 5 s). Perfect for stress-testing your HMI or dashboard without a real device.

• Configurable serial parameters — baud rate, data bits, stop bits, parity, and timeout — all the knobs you need for legacy hardware.

• Write registers easily — send FC06 (single register), FC16 (multiple registers), or FC05/FC15 (coils) writes from a dedicated panel without leaving the main view.

• Native macOS app — built with Tauri and Rust for a tiny footprint, fast startup, and full Apple Silicon support. No Java, no Electron bloat.

WHO IT'S FOR

• Automation engineers commissioning new PLC installations

• Field technicians troubleshooting Modbus sensors and meters

• Firmware developers validating their Modbus slave implementations — use the built-in server to simulate responses without writing a single line of code

• Students learning industrial communication protocols

• Anyone who needs a reliable Modbus master and slave simulator that just works

WHY MODBUS POLL

Most Modbus tools are stuck in the Windows-95 era — cluttered toolbars, confusing dialogs, and decade-old UIs. Modbus Poll brings the same proven functionality to a modern, dark-themed interface that respects your screen and your time. Everything you need is one click away. Nothing you don't is in the way.

Whether you're polling a single device on your bench, troubleshooting a Modbus TCP gateway in the field, or simulating a slave device for your team to test against — Modbus Poll gets you to answers faster.