Temperature sensor failure detection arrangement using a heater energy counter
US4788398A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 30, 1987 |
| Grant date | Nov 29, 1988 |
| Priority date | — |
| Expiry date | Sep 30, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05D23/24
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An improved temperature sensor failure detection arrangement for a temperature controlled heating device of the type having a heater, an electronic controller for controlling the power level applied to the heater, and a temperature sensor. The controller includes an internal heater energy counter, which is incremented and decremented at rates determined as a function of the power level applied to the heater such that the count of the heater energy counter approximately tracks the temperature of the heater. The controller periodically compares temperature information from the temperature sensor with the count of the heater energy counter to check for abnormal operating condition of the temperature sensor. An abnormal condition is detected when the count of the heater energy counter is within a predetermined reference range and the sensed temperature is outside a correlative predetermined reference temperature range, which ranges are selected such that under normal operating conditions, whenever the count is within the predetermined range, the temperature will be within the reference temperature range.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.