Solis Inverter Modbus: Register Offset Trap You’ve got your Solis inverter wired to a USB-to-RS485 adapter, QModMaster is talking to it (wrong slave address gives timeouts, the right one answers) — but every register read comes back Exception Code 02: Illegal Address. The wiring is fine, the baud rate is fine, and the slave ID…
Read Carlo Gavazzi EM24 with QModMaster (Watch the Word Order!) You’ve got the Carlo Gavazzi EM24 energy meter wired up, QModMaster returns registers without errors — and the numbers are nonsense. Voltage reads as millions of volts, or the power figure is off by a factor of 65,536. Before you rewire anything: the EM24 uses…
Verify Deye Inverter Registers with QModMaster Writing a Home Assistant register definition for a Deye inverter from the Modbus manual alone is how garbage sensors get born. The advice from the Deye Modbus TCP integration project (leonelfaugusto/deye-modbus-tcp) is blunt: use a Modbus client like QModMaster to verify every register against the live inverter before writing…
Test Sungrow Inverter Modbus with QModMaster If you’re wiring a Sungrow SH-series inverter into Home Assistant and the sensors come up empty, don’t start by rewriting your YAML. The troubleshooting guide of the popular Sungrow Modbus integration (mkaiser) recommends the same first step: check whether the Modbus connection works at all, using QModMaster — their…
Waveshare Gateway: ModbusTCP Mode vs Transparent Mode (8899) Waveshare’s RS-485-to-Ethernet gateways ship with two completely different operating modes, and picking the wrong one is why your QModMaster connection either works perfectly or fails in confusing ways. This guide explains ModbusTCP conversion mode (port 502) vs transparent transmission mode (port 8899), which one to choose, and…
Read Your Growatt Inverter with QModMaster via Modbus This is a first-read walkthrough for Growatt solar inverters using QModMaster, the free open-source (LGPLv3) Modbus master simulator from the upstream project. The settings below come from a community-tested setup — a Growatt SPH10000TL3 BH-UP read through a PUSR gateway, with function code 0x04 starting at address…
Read an Eastron SDM230 Energy Meter with QModMaster The Eastron SDM230 is a single-phase DIN-rail energy meter that publishes voltage, current, active power, power factor and cumulative kWh over RS-485 using Modbus RTU. It is one of the most common meters in home-energy monitoring projects, and it is an ideal first device to read with…
Test Your SMA Sunny Boy Inverter Over Modbus with QModMaster Before wiring a home automation system into your SMA Sunny Boy inverter, test the connection with a standalone Modbus master. QModMaster is free, open source (LGPLv3), and does exactly one job well: it lets you talk to a Modbus device manually and see the raw…
Modbus RTU to TCP Gateway Guide (2026) A Modbus RTU to TCP gateway (also called a serial server or serial device server) lets Modbus RTU devices on an RS485 bus appear as if they were Modbus TCP devices on your network. In one sentence: it translates between serial RTU frames and TCP packets, so your…
USB to RS485 Adapter Buying Guide for Modbus (2026) QModMaster talks Modbus RTU over a serial port — but modern PCs don’t have serial ports. A USB to RS485 adapter is the piece of hardware that bridges that gap: it plugs into USB on one end and gives you the A/B (D+/D−) screw terminals your…
