Variable liftoff voltage process field device

• Main Author: SCHULTE JOHN P
• Format: Patent
• Language: English
• Published: 28.06.2011
• Subjects: CONTROL OR REGULATING SYSTEMS IN GENERAL; CONTROLLING; ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS ORELEMENTS; PHYSICS; REGULATING; SIGNALLING; TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHICCOMMUNICATION; TRANSMISSION SYSTEMS FOR MEASURED VALUES, CONTROL OR SIMILARSIGNALS

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.