Software developments for modbus SCADA to extend distance to 2x for controlled devices

摘要

Modbus protocol is a protocol that is widely used in SCADA systems. Because it is an open standard protocol. It can be programmed for communications in embedded devices easily. When using the Modbus protocol on RS-485 bus systems, the communication distance is limited to 1.2 km; typically a repeater is used to boost the signal to further the distance. This paper presents an OPC Server and Firmware update to increase the working distance of the control devices. The update is also compatible with existing standard devices as well.