The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 30, 1985
Filed:
Mar. 12, 1982
Hermann Dietz, Gerlingen, DE;
Ferdinand Grob, Besigheim, DE;
Klaus Muller, Tamm, DE;
Harald Reber, Gerlingen, DE;
Robert Bosch GmbH, Stuttgart, DE;
Abstract
To permit calibrating and testing a current-limiting sensor in situ, the sensor is exposed, from time to time, to ambient air forming a standard gas, and the output thereof compared with a standard, for example by connecting a resistor (4) of standard value in circuit therewith or for recalling from a memory (23) in a microcomputer (22) standard conditions; upon determination of a deviation between output from the sensor (2) when exposed to the standard gas--typically air--and the theoretical value as stored, the theoretical or reference value is reset if the deviation is within a predetermined limit or, otherwise, an alarm output is provided. The tolerance limits can be set in such a way that a first alarm output is provided in a narrow tolerance, thus indicating drift of the sensor toward eventual malfunction, and permitting utilization of the sensor for long lifetime, while providing advance warning of imminent failure. Change of applied voltage to the sensor and test for current therethrough can then derive an actual operating curve which can be compared with stored test curves in the memory from which, upon extrapolation, a tendency to failure can be predicted and recognized.