| 摘要 |
PURPOSE:To easily detect the incomplete disconnection of a signal circuit by transmitting the pulse signals in a fixed cycle with superposition on the DC voltage, charging the capacitor set at the termination of the signal circuit for each output of the pulse signal, and comparing the peak value of the charging current with a prescribed level. CONSTITUTION:The pulse signal of peak value V1 is superposed on the DC voltage V of a signal circuit l and transmitted, and a capacitor C is charged by the pulse signal via the circuit l. The charging current of the capacitor C increases and decreases according as decrease and increase of the resistance value of the circuit l respectively. As a result, the disconnection can be decided when the charging current of the capacitor C is reduced less than a prescribed level after monitoring the peak value of the charging current at the termination side of the circuit l. Thus the disconnection phenomena including the incomplete disconnection of the line can be easily detected. |
