| 摘要 |
PROBLEM TO BE SOLVED: To provide a device capable of displaying a protection function based on duplex constitution at the time of occurrence of a failure and accurately preventing also the occurrence of duplex system switching malfunction even when a trouble occurs in a diagnostic signal transmitting/receiving cable or the like mutually connecting both systems. SOLUTION: The device is provided with duplex constitution consisting of a current system 1 and a stand-by system 2. A diagnostic signal transmitting/ receiving cable A for mutually connecting the current and stand-by systems 1, 2 is used, pilot signal transmitting/receiving parts 25, 26 are connected to one end side of the cable A and a returning part for returning a transmitted pilot signal (e) is connected to the other end side of the cable A. A pilot signal monitoring means 24 for monitoring whether the transmission/reception of the pilot signal (e) by the transmitting/receiving parts 25, 26 is normally executed or not judges a diagnostic signal from the current system 1 only when the pilot signal (e) is normally transmitted/received. |
