POWER EFFICIENCY CIRCUIT

摘要

A radar level gauge for measuring a level of a surface of a product in a tank having a two-wire process control loop (20), output circuitry (32, 33, 35) coupled to the two-wire process control loop (20) for setting in the loop a desired value of a loop current (Iloop) corresponding to the product level, a power supply circuitry (30, 41) coupled to the two-wire process control loop (20) for receiving power from the loop (20) and being a source of power for a microwave source, a microwave receiver, a measurement circuitry and the output circuitry (32, 33, 35) and including a converter (30) for transferring power from the loop (20) to said powerA radar level gauge for measuring a level of a surface of a product in a tank having a two-wire process control loop (20), output circuitry (32, 33, 35) coupled to the two-wire process control loop (20) for setting in the loop a desired value of a loop current (Iloop) corresponding to the product level, a power supply circuitry (30, 41) coupled to the two-wire process control loop (20) for receiving power from the loop (20) and being a source of power for a microwave source, a microwave receiver, a measurement circuitry and the output circuitry (32, 33, 35) and including a converter (30) for transferring power from the loop (20) to said power supply circuitry by means of feeding a first current (IDC/DC) from the loop (20) to the power supply circuitry (30, 41), a current generator (32) included in said output circuitry (32, 33, 35) for generating in parallel to said first current a second current (Ish) in the loop (20) for maintaining said loop current at a value corresponding to said product level and a sensing circuit (38) for determining the value of said second current and having an output indicative of the value of said second current.