| 摘要 |
A diagnostic circuit (18) for a potentiometric sensor (10) having an electrically resistive means (12) and a sliding contact (14) in connection with the resistive means and providing an output from the sensor at a sensor output terminal (16), the diagnostic circuit comprising a low pass filter (36) connectable between the sliding contact and the sensor output terminal; alternating voltage supply means (20,21,22,24) having a high impedance connectable to the sliding contact; and amplitude modulation demodulating means (30,32,34) connectable between the sliding contact and a diagnostic output terminal (38), the voltage at the diagnostic output terminal providing an indication of the contact resistance between the sliding contact and the resistive means of the sensor. Monitors the contact resistance without interfering with the sensor output.
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