| 摘要 |
PURPOSE:To discriminate the presence/absence of a fault in a vehicle-side information receiving means by monitoring a back electromotive force which is generated in a second coil for a prescribed period of time at the moment an excitation voltage becomes zero. CONSTITUTION:An excitation pulse is supplied 26 and 27 to a second coil 14 through a selected 28 specific channel. A comparator 24 transforms the waveform signals of the excitation voltage, back electromotive force, etc., of the coil 14 into H and L binary waveforms after the waveform signals are compressed 31 and level-shifted 30 and the waveforms are stored 36. Timing signals supplied to the storage device 36 at prescribed time intervals rise when the excitation voltage becomes zero and the back electromotive force is generated during the normal operation of this device. When the back electromotive force is generated in a normal pattern, the level of the force becomes low during moss of the generating period and, when the level becomes high at the rising time of the timing signal, the electromotive forces is generated only during a short period. In such case, it is discriminated 32 that an information receiving means is abnormal, namely, a short occurs on the front end side of a cable 16. When the force is not generated even though the excitation pulse is supplied 27, it is discriminated 32 that disconnection occurs on the front end side of the cable 16 or disconnection or a short occurs on the root side of the cable 16. |
