ELECTRONIC BORDERING SYSTEM

摘要

An electronic bordering system (1) for a working tool (2), in which a border cable (3), i.e. an electric cable, is placed above, under or on ground or floor, so that it separates an inner area (4) within the border cable (3) from an outer area (5). The working tool is preferably intended for attendance of ground or floor, such as grass-cutting, vacuum-cleaning, etc. A signal generator (6) feeds the border cable with current, whose magnetic field (7) affects at least one sensing unit (8) located on the working tool, so that the sensing unit emits signals (9) to a control unit (10), which in cooperation with an engine control (11), or a signal system for a driver, and at least one driving source (12, 13) directs the tool's movement in order to prevent it from remoting from the inner area. The signal generator feeds the border cable with current containing at least two alternating-current components (14, 15) of different frequency, and the components are lying in a known relation of time to each other. Thereby the control unit can evaluate the difference in the signals (9) caused by the magnetic field's different directions in the inner area (4) and the outer area (5), and the control unit can emit an area signal (16), which mainly takes up one of two states depending on the position of the sensing unit in relation to the border cable, i.e. an outer area state (17) or an inner area state (18).