With advantage of long distance transmission, fiber optics gets more and more wide application in data communication field. Normally, under complicated electromagnetic condition, or outdoor with long distance, fiber optic communication will be the first choice. It takes fiber optic Modem to convert RS-485 to fiber optic. There are two communication modes: point to point and point to multipoint communication. When main control equipment is far from slave control equipment, it would be point to point mode; when the communications points are disperse, it would be point to multipoint.
Multipoint multi equipments long distance communication;
A. Full isolation, solve weak electric potential which causing burning on RS-485/422 BUS problem
B. Fiber optic communication, solve long distance communication problem. In theory, the transmission distance for RS-485/422 IS 1,200m, even you use relay, the transmission distance only 1,200m further; sometimes we can’t reach this distance when it influenced by nodes and transmission rate; and long transmission distance is easier to burn electric potential. Fiber optic communication will solve long transmission distance problem without using relay and the limitation of nodes. It is the best choice for multipoint multi equipments communication.