Method and arrangement for monitoring the operability of a probe heating device

US5285762A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Peter Werner · Wiernsheim, DE
• Hermann Hemminger · Markgröningen, DE
• Hubert Schweiggart · Stuttgart, DE
• Andreas Werner · Königstein, DE

Key dates

• Filing date: Jun 22, 1992
• Grant date: Feb 15, 1994
• Expiry date: Jun 22, 2012

Classification

• Technology area (CPC G): Physics
• CPC primary: G01N27/417
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A system for monitoring the operability of a probe heating device is introduced which comprises a probe heater, an arrangement which supplies the probe heater with the necessary electrical energy and the corresponding supply leads. The essence of the invention is that the heating current for a probe heater causes a measuring voltage on a measuring resistor connected in series with the probe heater. The measuring voltage is compared to a further voltage which is emitted by a reference element. The reference element is at a similar temperature as the measuring resistor or receives a measuring signal which corresponds to the temperature of the measuring resistor and emits a voltage which has a similar temperature response as the measuring voltage. By means of this comparison of both voltages, it is possible to conclude as to the current flowing through the heater and therefore as to the operability of the probe heating device without switching too high a resistor in series with the probe heater.