Electronic protection for series communication line of an elevator, has opto-coupler receiving signal indicating short circuit between two supply wires

摘要

Between fourth terminal (CN1-4) of input connector and fourth terminals (CN3-4,CN4-4) of output connectors is a first 30 volt direct current supply wire (12). On this supply wire is mounted in series the input terminal of a first contact (REL1), an output terminal of the contact, a positive temperature coefficient resistance (CTP) and a diode (D1). At the terminals of resistance (CTP) are connected a resistance (R1), a Zener diode (DZ1) and an opto-coupler (OPT1) in series. . The protection circuit includes: (a) a input connector (CN1) with four terminals (CN1-4) connected to an input bus; an output connector s (CN3,CN4) each with four terminals (CN3-4, CN4-4); a first supply connection with feed wires (12,25) and second supply connection with feed wires (18,26); a series line connection with series wires (L1,29) and a second series line connection with series wires (L2,27) for transmitting data from a controller; detection and analysis means (10) to permanently monitor accidental contact between, the wires (25,29), (25,27), and (25,26); detection and analysis means (30) to permanently monitor accidental contact between, the wires (26,29), (26,27), and (29,27). protection relays (REL1 to REL4) for protecting circuits situated in front of the electronic device, and; and trigger switches (REL1-A,REL1-F) to isolate the protection relays.