Vehicle detector system with automatic loop checking
US7109887B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 20, 2003 |
| Grant date | Sep 19, 2006 |
| Priority date | — |
| Expiry date | Nov 20, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08G1/042
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A method and apparatus for automatically testing the integrity of an inductive loop in a vehicle detector system. A check loop is placed adjacent each inductive loop in a multi-channel vehicle detector system. Each check loop is periodically activated by the vehicle detector to simulate a vehicle load on the associated inductive loop. Samples representing loop inductance at different activation periods are compared with a standard. When the result exceeds the standard, the inductive loop is subjected to additional sample testing with decreasing time intervals between sampling. After a number of additional samples exceed the standard, the inductive loop is deemed failed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.