| 摘要 |
<p>PURPOSE:To obtain a disconnection detecting voltage by applying a common conductive sheath to a signal input wire and applying a disconnection detection signal to the conductive sheath to give polarity to the disconnection detection signal induced in the signal input wire through electrostatic coupling by means of a diode fitted to each signal input wire. CONSTITUTION:An Sl represents the disconnection of a signal source located at a sufficiently remote location and is illustrated as a simulated disconnection switch. When the Sl is closed, that is, the line is not disconnected, a DC voltage charged in a filter capacitor Cf is discharged via a remote signal source (Sl in this embodiment) and a resistor Rf, then disconnection detecting voltage is not almost generated. The disconnection detection voltage is set to a value over the reading range and analog and is read by the method above. Since the voltage of the signal source is read normally and the disconnection detection voltage is read at disconnection, the disconnection is detected by data scale over.</p> |
