Gas detecting apparatus having condition monitoring means
US6123818A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 28, 1997 |
| Grant date | Sep 26, 2000 |
| Priority date | — |
| Expiry date | Oct 28, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N27/4163
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An operational amplifier (34) has its inverting input connected to a electrochemical gas sensor (38) for amplifying the current produced thereby in response to presence of a predetermined gas. In order to determine whether a sensor (38) is indeed present and that a sensor present is serviceable, a transient is applied to the non-inverting input of the operation amplifier (34). The presence or absence of the sensor (38) alters the transfer function of the operational amplifier (34) in respect of the test signal. If a serviceable sensor (38) is present, the gain of the operational amplifier (34) is high for the transient resulting at square pulse output. However, if a serviceable sensor (38) is not present, the gain of the operational amplifier (34) is relatively low and the transient retains its original form. Consequently the presence of a serviceable sensor (38) can be determined from the output of the operational amplifier (34) in response to the transient test signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.