| 摘要 |
<p>A system has a sensor 3 on a fuel tank coupled magnetically with a float gauge fitted inside the tank, and provides a visual indication of the tank level and an electrical signal to a measurement unit (MU 2). The MU 2 is a battery-powered, microprocessor-controlled device located at the fuel tank. It logs the sensor reading at predefined times and periodically tranmits the level history to a transmitter unit (TU 4) using radio frequencies. The TU 4 is a battery-powered, microprocessor-controlled receiver device that periodically receives and stores the level history from the MU 2. It scans the received level history for alarm limit breaches, and on alarm and on a periodic basis dials over the public telephone network 5 to a monitoring centre to deliver the level history.</p> |
