TWO-WIRE LEVEL TRANSMITTER.

摘要

A level transmitter (10) for use in a process application measures height of a product (14) in a tank (12). The level transmitter (10) includes a microwave antenna (18) directed into the tank (10). A low power microwave source (70) sends a microwave signal through the microwave antenna (18). A low power microwave receiver (70) receives a reflected microwave signal. Measurement circuitry (42) coupled to the source and receiver initiates transmitting of the microwave signal and determines product height based upon the received, reflected signal. Output circuitry (48, 56) coupled to a two-wire process control loop (20) transmits information related to product height over the loop (20). Power supply circuitry (40) in the level transmitter (10) coupled to the two-wire process control loop (20) receives power from the loop (20) which powers the level transmitter (10) including the microwave source and the microwave receiver (70).