| 摘要 |
A fault detection apparatus comprises a thermocouple sensor junction 10, a differential output amplifier 20 connected to the thermocouple sensor junction to provide an output temperature signal. An alternating voltage source 22 is connected to a first side of the thermocouple sensor junction via a first conductor, and a detector 26 is connected to a second side of the thermocouple sensor junction via a second conductor, wherein each of the first and second conductors is connected to the output amplifier via a low pass filter 16, 18 and the detector is configured to provide a fault indicating output when an AC test signal at the detector is outside of a predetermined range. A plurality of thermocouple sensor junctions may be provided connected to the alternating voltage in parallel and the output amplifier connected via a multiplexer.
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