The OPTONET system monitors the position of up to 30 ON/OFF fiber optic limit switches. It is based on Optical Time Domain Reflectometry : an optical pulse emitted by a pulsed laser diode is splitted between the sensors by an optical star coupler. Delay lines are inserted on the optical lines in order to separate the pulses backreflected by the switches. This paper establishes the main characteristics of the OPTONET system from an user point of view. These characteristics depend on the optical fiber properties and the time domain multiplexing method. The well known optical fiber properties lead to high EMI immunity, lightweight, galvanic isolation, in particular while the time domain multiplexing leads to saving in cable, weight and cost, and it requires only the use of a single source and detector. Moreover, various limit fiber optic switches may be connected to the network since the OPTONET system operates properly with any reflective switches. The number of sensors which may be monitored by the system will be examined. The OPTONET system is presently used on several industrial plants and these applications will be presented. Finally, the future developments of the system will be presented and discussed.

Date Published: 1 August 1990
PDF: 10 pages
Proc. SPIE 1267, Fiber Optic Sensors IV, (1 August 1990); doi: 10.1117/12.20296

Published in SPIE Proceedings Vol. 1267:
Fiber Optic Sensors IV
Ralf Th. Kersten, Editor(s)