Remote control system for machinery in areas exposed to thunderstorms - uses LEDs at transmitter and receiver to indicate shorts and breaks in control line

摘要

The remote control system, for use in areas exposed to the weather -- especially thunderstorms, has its control lines supplied with AC and diodes at the transmit and receive ends. (The remote control device, e.g. a relay, is operated over the receive-end diode). To enable the operator and receiver to see that the control line is not short circuited or broken, these two diodes are of a light emitting type. The LEDs have the advantage in that their electrical characteristics (forward volts etc.) are not so different from those of ordinary diodes and in their responding to very small control currents -- provided there is no short circuit or break.