Well-known serial buses for distributed control of backup power plants. RS-485 versus controller area network (CAN) solutions

Networking is increasingly becoming a feature of industrial products such as those for medical devices, vending machines, machine tool, and, the example analyzed here, modular power plants. As many such systems depend on cheap microcontrollers, a common approach to networking has been based on the combination of the available standard serial communication controller (UART) normally included in such devices and RS-485 drivers. However UART-based network protocols do have some potential disadvantages. Controller area network (CAN) offers an attractive alternative due to the availability and low cost of CAN based devices. This paper compares these two approaches in the design of a serial bus, devoted to internal interconnection in a commercial range of modular power backup systems, and describes the migration process from the first to the second solution.