Field device for determining a process variable in process automation

US11199826B2 · kind B2 · utility

Assignee

• Siemens Aktiengesellschaft · DE

Inventors

• Joachim Hepp · Waldbronn, DE
• Adrian Mucha · Karlsruhe, DE

Key dates

• Filing date: Apr 28, 2017
• Grant date: Dec 14, 2021
• Expiry date: Jun 10, 2038

Classification

• Technology area (CPC G): Physics
• CPC primary: G05B2219/25428
• WIPO field: Control
• WIPO sector: Instruments

Abstract

A field device which outputs a measured value and includes a self-diagnosis function which, when at least one specified error is detected, signals this error, marks the output measured value as temporarily invalid, and initiates the output of a substitute value that is used to trigger a safety-oriented response, where to prevent interventions when temporary errors occur, but without losing safety-relevant information, the field device includes a first and second timers having different expiration times that are started when the error is detected and are reset at the end of the detected error, where the first timer initiates the output of the substitute value when the first expiration time expires, where the second timer signals the error when the second expiration time expires, and where the signal is resettable if, at the same time, the output measured value is marked as valid via the second binary status signal.