| 摘要 |
<p>PURPOSE:To omit a cable exclusive for informing a decrease in gas pressure by intermitting a low-frequency output comprising trio pulses for standardizing a failed repeater because of the decrease in the gas pressure to distinguish the drop of the gas pressure from a failure in a transmission line. CONSTITUTION:A low-frequency oscillator operated by an output of a gas pressure sensor and a switch operated by a signal of the oscillator are provided. When the gas pressure sensor detects the drop of gas pressure, the switch is actuated to intermit a supervisory signal comprising the trio pulses for searching a failed repeater, thereby distinguishing the drop of gas pressure from a filure of a transmission line and a repeater. Thus, a cable exclusive for informing the information of gas pressure drop is omitted. Moreover, a supervisory device offers information easy to read such as supervisory by interruption of supervisory signal, extinguishment of a lamp at a failure of transmission line, flickering of a lamp at decreased gas pressure, and lighting of lamp at a normal state.</p> |
