| 摘要 |
A field transmitter includes field device circuitry configured to measure or control a process variable. A first process control loop terminal is configured to couple to a two-wire process control loop which carries a loop current. A second process control loop terminal configured to couple to the two-wire process control loop. A switching regulator has an input and an output. The output is coupled to the transmitter circuitry and arranged to provide power to the transmitter circuitry. A variable voltage source having an input electrically coupled to the first process control loop terminal, and a voltage output coupled to the input of the switching regulator and a control input. The voltage output is a function of the control input.
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