Proximity switch, which indicates the presence or absence of field changing objects at a defined distance from the proximity switch by a binary signal with the aid of excitation and detection of a field

US4502042A · kind A · utility

Assignee

• MAN Roland Druckmaschinen AG · DE

Inventors

• Arno Wuhrl · Mühlheim am Main, DE
• Werner Kistner · Offenbach am Main, DE

Key dates

• Filing date: Mar 18, 1982
• Grant date: Feb 26, 1985
• Expiry date: Mar 18, 2002

Classification

• Technology area (CPC G): Physics
• CPC primary: G01V3/102
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A multi-position proximity switch having a plurality of binary outputs, each output indicating whether the distance between an object and a field transducer exceeds a corresponding one of a plurality of predefined distances. The sensitivity of a proximity detector having a single binary output is stepped through a plurality of adjustable levels by a digital counter having decoded outputs and the binary output of the proximity switch is sampled after the decoded counter outputs change state so that a plurality of binary outputs, each associated with a detector sensitivity level and a corresponding distance, are provided. The failure of the greatest distance to be detected or the detection of the smallest distance activates an alarm indicating that the object is outside a permissible range of distances.