| 摘要 |
A remote level sensor for a residential fuel oil tank is adapted for a fuel oil gauge with a permanent magnet which changes position with changing fluid levels in the tank. The sensor has a housing with a connector which receives a top portion of the gauge such as to provide an alignment of the sensor with the gauge. The sensor is connected to a telephone line, and makes use of a current from the "tip" and "ring" lines of the telephone connection to supplement the power of an on-board battery. The sensor has multiple reed switches each in a different relative position. The reed switches thus each close when the magnet is in a different position, and thereby close when the fluid in the tank is at a different level. The controller has a sampling routine which responds to the detection of a closure of one of the switches by seizing the telephone line, dialing a central monitoring location and transmitting information to the central location indicating which of the switches was closed. A memory unit is provided in which multiple telephone numbers are stored so that the controller can call a second number when no response is received using a first number.
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