In building automation, for example, temperature and humidity are often communicated to a computer for long term storage. Modbus is typically used to transmit data from control instrumentation to a logic controller or a system for archiving data. Modbus is used widely by many manufacturers throughout many industries. It is the most pervasive communications protocol in industrial automation and is now the most commonly available means of connecting industrial electronic devices.
Modbus RTU is an open standard, meaning that manufacturers can build it into their equipment without having to pay royalties. Almost as old as the first Programmable Logic Controller, the Modicon 084, which in those days was called a PC for programmable Controller. In today’s age of Internet connectivity and Web Services, Modbus’ unconnected message and simple request-response communication structure are almost quaint. It truly is as old as the hills and has the whiskers to prove it. You might call the Modbus protocol the grandfather of industrial networking.
