ABB BR432 and BR432-885 Thermostat Modbus Protocol

This document defines the Modbus communication protocol for ABB BR432 and BR432-885 thermostats, detailing the RS485 interface, register mapping, and command frames for reading and setting thermostat parameters. It specifies the thermostat as a Modbus slave device, covering baud rate, byte format, CRC checksums, and register addresses for device information, temperature control, and system state.