BR484/BR484-885 Thermostat Modbus RTU Protocol Specification

This document defines the Modbus RTU communication protocol for ABB BR series thermostats (models BR484/BR484-885) with 0-10Vdc output and RS485 interface. It specifies the master-slave frame formats for reading and setting thermostat parameters, including address configuration, command codes (03 and 06), CRC-16 checksums, and detailed register mappings for status, mode, fan speed, set temperature, compensated temperature, and time settings.