| 摘要 |
A radar level gauge using microwaves coupable to a two-wire process control loop for measuring level of a product in a tank. A microwave antenna unit is directable into the tank. A low power microwave source sends a microwave signal through the antenna unit into the tank. A low power microwave receiver receives a reflected microwave signal from a surface of the product in the tank. Measurement circuitry coupled to the source and receiver initiates transmission of the microwave signal and for determining product level based upon the received signal. Output circuitry coupled to the two-wire process control loop transmits information related to product level over the loop. Power supply circuitry coupled to the two-wire process control loop receives power from the loop being the sole source of power for the low power microwave source, the low power microwave receiver, the measurement circuitry and the output circuitry in the radar level gauge. An isolation circuit non-conductively transfers power from the loop to the power supply circuitry and non-conductively transmits the information between the output circuitry and the loop.
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