Electric balance

US4625818A · kind A · utility

Assignee

• Sartorius AG · DE

Inventors

• Erich Knothe · Bovenden, DE
• Franz-Josef Melcher · Hardegsen, DE
• Christoph Berg · Oettingen, DE

Key dates

• Filing date: Mar 18, 1985
• Grant date: Dec 2, 1986
• Expiry date: Mar 18, 2005

Classification

• Technology area (CPC G): Physics
• CPC primary: G01G7/04
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

The invention suggests an intermittent mode of operation to reduce the stray power in the coil in a balance based on the principle of the electromagnetic compensation of force. To this end, switching means (21) are provided which can interrupt the current flow through the coil (11) so that when the current flow is interrupted, the movable parts (2-9) of the balance move against one of the stops (24) or (25). These switching means (21) are controlled by the digital signal processing unit (18). In addition storage means (20) are provided within the framework of the digital signal processing unit which store the last-determined weight value for the duration of the interruption of the current flow through the coil.