FARADAY CUP SYSTEM CONTROL LOGIC ON THE WIND SPACECRAFT

International Telemetering Conference Proceedings / November 04-07, 1991 / Riviera Hotel and Convention Center, Las Vegas, NevadaA satellite-mounted instrument has been developed to measure the energy spectrum of the solar proton flux in the solar wind. The instrument consists of a sensor --- the Faraday Cup, an analog signal processing chain, a high voltage modulator and a digital section. This paper presents the digital section designed and built in our laboratory which functions well to (a) interface with the main processor, (b) to provide the logic signals with proper timing to the analog circuitry, (c) to deliver the necessary bit pattern to the high voltage modulator, (d) to provide the calibration mode control signals when necessary, and (e) to synchronize the sequence of events at the begining of every spacecraft rotation. As with all space projects primary concerns beyond the logical functionality consistes of circuit power consumption, instrumental mass, radiation tolerance levels, stability with respect to temperature, and relative ease of component procurement. The NASA WIND laboratory spacecraft that will carry the experiment is due to be launched in December of 1992 and eventually come to park in an orbit at the first Lagrangian point.International Foundation for TelemeteringProceedings from the International Telemetering Conference are made available by the International Foundation for Telemetering and the University of Arizona Libraries. Visit http://www.telemetry.org/index.php/contact-us if you have questions about items in this collection

Event-driven model of unreliable production lines with storage

Summarization: We have developed an event-driven algorithm for simulating a factory production line with storage. Using this algorithm, a production line, with an arbitrary number of machines each processing items at different rates and with buffers of any size, can be modeled efficiently. The algorithm is based on computing the time to the next event for each buffer and machine, where the events are: a buffer becomes full, a buffer becomes empty, a machine fails, and a machine is repaired. By collapsing the production line to exclude empty buffers that stay empty and full buffers that stay full, piece-by-piece computation is avoided. Computation time is reduced further by updating a buffer only when the input or output rate of that buffer changes or when the state of that buffer changes. An example of a line consisting of 100 machines and 99 buffers illustrates the efficiency of the model.Presented on: International Journal of Production Researc