AN ADVANCED OPTICAL FIELDBUS INSTRUMENTATION SYSTEM USING 16×16 REFLECTION TYPE OPTICAL STAR COUPLER AND LOW POWERED TRANSMITTER

摘要

Optical fieldbus instrumentation system represented by FFI~(TM) has been supplied to many customers since 1985. The international optical fieldbus system standardization is progressing satisfactorily as "IEC and ISA draft standard". This paper reports the advanced optical fieldbus system which conforms to this draft standard. The system described is a bidirectional multiplexing optical fiber digital transmission network constituting of system controllers, transmitters, actuators and reflection type star couplers which enable the communication between these devices to obtain a distributed control system in an instrumentation field. The transmission rate is 31.25Kbit/s. Transmitter is powered by a battery. To extend the battery life, the transmitter uses low-power consumption circuits, and operates by switching on and off supply of power and clock pulses to the electronic circuit based on sensing, calculation and data transmission periods of time. The star coupler is comprised of 16 input/output ports and an optical wave guide for light mixing.