Supervision system for monitoring the integrity of a transmission line
US4529970A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 18, 1982 |
| Grant date | Jul 16, 1985 |
| Priority date | — |
| Expiry date | Oct 18, 2002 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B29/06
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
The integrity of a two-conductor transmission line, over which d-c energizing voltage is supplied to a series of shunt-connected detectors (such as fire and/or smoke detectors) and which line is terminated by an end-of-line capacitor, is monitored and repetitively tested by periodically and momentarily interrupting the application of the d-c energizing voltage to the transmission line or conductor pair, while at the same time connecting a resistive load across the line's input end to provide a discharge path for the capacitor. If the integrity is normal, meaning that the line is continuous and not open, and has no excessively high series resistance or excessively low shunt resistance, and also meaning that the capacitor is functioning normally and is not deteriorated, the capacitor will discharge very little during each test and will maintain a relatively high voltage across the resistive load. On the other hand, if there is any trouble on the line giving rise to abnormal integrity, a relatively low voltage will be developed across the resistive load during each test. By sensing the resistive load voltage, the integrity can therefore be determined. When the integrity is found to be…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.