In this paper, we developed the library for the microcontroller platform Arduino to apply in Modbus SCADA systems. This library allows Arduino board to communicate with RS-485 and use Modbus protocol which transmits data via a redundant bus. Experiments are conducted to compare the stability of data communication between a regular bus and a redundant bus which is the developed library. The results show the developed library Arduino board is able to communicate with redundant buses and more resistant to faults than conventional buses.
