| 摘要 |
PURPOSE:To facilitate the recognition of abnormality by outputting a signal with repetitive waveform instead of a measured value when a transmitter becomes abnormal. CONSTITUTION:If abnormality occurs, it is discriminated which of a sensor 1 and an electric system causes the abnormality. The fault of the sensor 1 can be judged from whether or not the sensor 1 generates an output outside of a predetermined output range. When a fault occurs to the sensor 1, the signal with waveform 12mA+2mA*sinomega1t is outputted to a transmission line 7. When electric circuit systems 4 and 5 become faulty, the sine-wave signal which has the waveform 12mA+2mA*sinomega2t, i.e. different frequency is outputted to the transmission line 7. Namely, the repetitive waveform is never outputted as long as the transmitter operates normally, so the abnormality is easily recognized from this repetitive waveform.
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