Electronic monitoring system with malfunction indicator
US4525699A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 17, 1983 |
| Grant date | Jun 25, 1985 |
| Priority date | — |
| Expiry date | Feb 17, 2003 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01F2007/1684
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A contactless motion detector, specifically an oscillator whose signal amplitude is attenuated or enhanced by the approach of a monitored metallic element, is periodically switched for brief periods into its alternate state by a train of short test pulses giving rise to corresponding checking pulses that are superimposed upon the integrated output voltage of the oscillator whereby that voltage is intermittently increased when at low level and/or intermittently reduced when at high level. These checking pulses, whether of the voltage-increasing or the voltage-reducing kind, are integrated to provide an enabling signal allowing a controlled load to be energized or de-energized according to the mean value of the output voltage; an absence of the enabling signal indicates a malfunction.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.