Signaling circuit and method to detect zone status
US9024616B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 29, 2012 |
| Grant date | May 5, 2015 |
| Priority date | — |
| Expiry date | Nov 7, 2033 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H3/06
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A bi-directional current limiter may be configured to receive an AC signal and bi-directionally limit the loop current to a predetermined current value. A first and second zone may be configured in series with the AC signal and bi-directional current limiter. The first and second zone may include unidirectional current limiters to limit a unidirectional current that is proportionately less than the bi-directionally limited current. A first opto-coupler circuit (ISO1) may be configured to detect both high and low current states in the current loop circuit. Second and third opto-coupler circuits (ISO2 and ISO3) associated with the first and second zones may be configured to detect only high current states in the current loop circuit. The status of the first and second zones may then be determined by an analysis of the current level in the current loop circuit during two half cycles as determined by the various current limiters.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.