Circuit for regulating and monitoring a signal current and measurement transducer with such a circuit

US8981744B2 · kind B2 · utility

Assignee

• ENDRESS+HAUSER GMBH+CO.KG · DE

Inventors

• Ralph Stib · Schongau, DE
• Wolfgang Trunzer · Lörrach, DE

Key dates

• Filing date: Jul 11, 2011
• Grant date: Mar 17, 2015
• Expiry date: Feb 4, 2032

Classification

• Technology area (CPC G): Physics
• CPC primary: G05F1/561
• WIPO field: Control
• WIPO sector: Instruments

Abstract

A circuit for regulating and monitoring a signal current, comprising a regulating circuit; and a monitoring circuit. The regulating circuit comprises: a first controlled voltage source for outputting a target value dependent controlled voltage; a current adjust circuit for adjusting the signal current in dependence on the controlled voltage and a first feedback voltage by means of a potentiometer; and a first feedback path, with at least one first resistance element across which the signal current flows. The voltage drop across the resistance element or one of the voltages of the current adjust circuit dependent thereon is supplied as a first feedback voltage. The monitoring circuit comprises: a second controlled voltage source for outputting a second target value dependent controlled voltage; an analog monitoring circuit for determining the deviation between the second controlled voltage and a second feedback voltage; and a second feedback path with a resistance element across which the signal current flows, wherein the voltage drop across the resistance element or a voltage of the monitoring circuit dependent thereon is supplied as a second feedback voltage.