| 摘要 |
PURPOSE:To monitor easily an inside state from outside, by branching a single cable piercing through the wall of an airtight or liquid-tight room into plural cables of different lengths and opening or short-circuiting the tips of these cables after connecting them to an object to be monitored. CONSTITUTION:A single cable piercing 104 through the wall 102 of an airtight or liquid-tight room is branched into branch cables 105a-105n of different lengths through a branching part 106. These branch cables are set as opposed to objects to be monitored, e.g., switch valves 101a-101n, and the tips 107a-107n of those branch cables are opened or short-circuited to switch the impedance. A control board 115 is operated to oscillate 108 pulses with the control of a CPU114. These pulses are sent to the cable tips set near the objects to be monitored via a branching device 106. Then the polarity of a reflected wave is decided 110 by a detecting circuit 109, and the receiving/transmitting time difference is measured 111. Thus the working state is decided 112 and displayed 113. The object to be monitored is specified from the time difference due to the difference of lengths of branch cables. In such a way, the remote monitor is possible with a simplified device. |
