| 摘要 |
A detection system for remote monitoring of a contact condition comprises first, second, and third impedance means, and four comparators. Each impedance means is selectively coupled between the contact and the comparators. With a known voltage applied at the third impedance means, the three impedances produce a unique signal voltage at the comparators depending on a condition of the contact closure. Each comparator may detect one of the four unique voltages and produce an electrical signal corresponding to the detected condition, which may be converted into an optical signal, and be transmitted in a fiber optic cable to a receiver where it is converted back into an electrical signal. Four detectors are each adapted to detect one of the electrical signals, and trigger a relay and status LEDs, indicating a contact condition consisting of: normally open/closed, and short/open circuited. A fifth detector monitors for broken fiber optic cable.
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