Our MPPT solar controller model number: MPPT5020-COM and MPPT5040-COM, with RS485 MODBUSprotocol. The RS485 MODBUS protocol defines  communicationbetween a host (master) and devices (slaves) that allows querying of deviceconfiguration and monitoring. MODBUS messages relay simple read and write operations on 16 bit words andbinary registers often referred to as “coils”.

       RS485is a physical interface, which is simply hardware. MODBUS is an internationalstandard communication protocol used to exchange data between devices fromdifferent manufacturers (usually for industrial use); The so-called protocolcan also be understood as the "language" someone said above, simplysoftware. In general, two devices transmit data through the MODBUS protocol,because it has a long transmission distance, and it is more commonly used ingeneral industrial sites.

       Our MPPT5020-BT and MPPT5040-BT transmit theworking parameters of the controller to the monitoring equipment in real timethrough the standard RS485 MODBUS protocol.