Optical, magnetic and capacitive technologies are widely used for signal isolation in industrial motor control applications. Digital isolators based on magnetic (transmission by transformer) methods have for the last decade provided a viable and often superior alternative, and when considered at a system level, may offer benefits not always recognized by system designers. This article by Dara O'Sullivan (DOSulli2)  and Maurice Moroney (The specified item was not found.) in EDN outlines the improved timing performance available from magnetic isolators, and the consequent system level benefits that accrue in motor control applications.