Drop height recorder

US4862394A · kind A · utility

Assignee

• Dallas Instruments Incorporated · US

Inventors

• David B. Thompson · Grand Prairie, US
• Stanley V. Preskitt · Dallas, US
• Harvey L. Downing · Garland, US
• Michael V. Allred · Irving, US

Key dates

• Filing date: Jan 28, 1987
• Grant date: Aug 29, 1989
• Expiry date: Jan 28, 2007

Classification

• Technology area (CPC G): Physics
• CPC primary: G01D9/005
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A drop height recorder apparatus includes a housing suitable for packaging for shipment from an origin point to a destination point, a triaxial accelerometer provides three signals to corresponding high gain and low gain channels. The three high gain channel signals are full wave rectified to change any negative signals to positive signals for summing into a single high gain "zero G" (free-fall) channel. AN analog to digital converter is connected to the three low gain channels, the single high gain channel, and to auxiliary sensors for digitizing the analog signals. A recorder has a programmable controller connected to the ADC for setting the digital sampling rate. The digitized low gain channel signals are passed through a digital trigger threshold comparator for comparison with a reference signal for generating event detecting trigger signals on the way to a delay memory which also receives the digitized high gain zero G signal and auxiliary signals. In response to a trigger signal the programmable controller reads out of the delay memory preselected numbers of pre-trigger and post-trigger data as an event sample either for a data processing memory for processing the signals for…