| 摘要 |
The liquid level within a storage tank network is continuously monitored by a transducer system of the present invention formed essentially of MSI's (Medium Scale Integrated Chips) including a differential pressure (dp) cell in circuit with a digital volt meter (DVM) which, in turn, is connected to a series of look-up ROM's (Read-Only Memories). In operation and as a function of dp cell output level, DVM is continuously applying BCD signals to the ROM's, such signals being proportional to liquid level. The ROM's retain, in memory, the Gray code translations of the BCD input. The ROM's are then periodically accessed via an analog multiplexer controlled by an oscillator/ripple counter to provide corresponding microcircuit level signals at the output of a 7-segment decoder/driver. Thereafter, the microcircuit signals are regenerated-at levels compatible with conventional MARK-SPACE tank gauging systems-using an isolation/driver network in circuit with the 7-segment decoder/driver. The aforementioned system is initiated by a MARK-SPACE interrogation signal and has special utility in digitally monitoring product/source levels within source/product storage tank networks associated with an oil refinery and/or a chemical complex.
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