Drop height recorder

摘要

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 desired information and storage in a storage memory or for a storage memory. A pre-selected number of event waveform signals together with time, date, and auxiliary data signals are stored in the storage memory. After recovery of the instrument, a personal computer can be attached for reading out the stored event waveforms from which the time of free-fall occurring during each event is determined and the drop height in inches computed. The personal computer is used prior to shipment to set the program parameters and operation modes in the programmable controller.