Security/fire alarm system with group-addressing remote sensors
US5268668A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 7, 1992 |
| Grant date | Dec 7, 1993 |
| Priority date | — |
| Expiry date | Jan 7, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B26/002
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A security/fire alarm system includes a plurality of event-sensors, e.g. intrusion and smoke sensors, each being identifiable by a unique digital address defined by a multibit binary address code. A central control unit operates to repeatedly address the sensors to determine their respective alarm and/or operating status. To minimize the cycle time required to sequentially interrogate all sensors, the central control unit operates to address groups of sensors simultaneously, each of the groups consisting of a sub-plurality of all the sensors. In response to being addressed, each sensor in an addressed group of sensors transmits a different binary bit or digit of a multibit digital response code which is defined collectively by the transmitted bits. The logical state of each of such binary bits indicates the general status (i.e. normal/abnormal) of the event-sensing unit that transmitted the bit. The control unit is responsive to the multibit response code to sequentially re-address only those event-sensing units that, through their respective binary bit, have indicated an abnormal status.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.