Reference Design for Simple Dual Redundancy

[jkurtw]

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In systems where the cost of failure is high, it is sometimes  advantageous to duplicate certain critical components.  This concept,  known as redundancy, helps improve the overall reliability of the system  by decreasing the probability of a failure.  This document discusses a  software method for implementing dual redundancy on a National  Instruments Real-Time controller such asCompactRIO,  Compact FieldPoint, or PXI.  The Simple Dual Redundancy (SDR) component is a set of LabVIEW VIs used  to implement dual-redundant control where one controller is active and  the other controller is in “hot standby” mode.  The controllers  communicate regularly with one another via a serial link so that if one  controller fails, the other will know to take control.  They also  exchange information about one another’s “health” so that the active  controller can determine whether or not it is in the best position to  remain in charge of the system.