// the find
ClassicDIY/ModbusTool
A modbus master and slave test tool with import and export functionality, supports TCP, UDP and RTU.
A Windows desktop GUI for testing Modbus master and slave devices over TCP, UDP, or serial RTU, with the ability to import and export register configurations. Aimed at industrial/embedded developers who need to poke at Modbus devices without writing throwaway test code.
The protocol layer (ModbusLib) is cleanly separated from the UI — codecs for each function code live in their own files, and client/server comm abstractions are split from the transport (IpClient, SerialPortClient), so the core library could theoretically be reused outside the WinForms shell. It covers all three transports (TCP, UDP, RTU) in one tool instead of forcing you to pick a separate utility per protocol. Distribution is handled properly: signed MSI releases plus a winget package, not just a zip on the releases page.
It's WinForms and Windows-only (SerialPort, .vdproj installer, Designer.cs everywhere) — no cross-platform story if you're testing from Linux or a Pi. There's no test project anywhere in the tree, so correctness of the codecs rests entirely on manual use. The README is just install instructions and a changelog; there's no documentation of the import/export file format, the wire behavior, or how to script it for CI-style device testing. Last push was October 2024, so open issues/PRs are likely sitting unaddressed.