Dual operating control circuits for intrusion detection systems
US4074248A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 22, 1976 |
| Grant date | Feb 14, 1978 |
| Priority date | — |
| Expiry date | Nov 22, 1996 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B17/00
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A series loop is in series with a control relay coil which has a first and a second contact. The first contact is coupled to an alarm and the second contact is coupled to one end of the loop. A control arm of the relay is operated by the coil to coact with said first contact when the coil is not energized and to coact with the second contact when the coil is energized to cause said second contact to latch said relay when the series loop is closed. Power is selectively applied to the control arm of the relay and a unidirectional current conducting circuit is coupled between the control arm of the relay and the second contact. The circuit supplies energizing current to the coil in the loop for the application of power to the control arm. This causes the relay to operate and therefore to latch if the loop is closed upon application of power to the control arm. The system user also is afforded a predetermined time to break the loop for purposes of leaving the premises and due to the nature of the unidirectional circuit, is assured that the intrusion system will be placed in a secured mode after the loop is broken.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.