Industrial motion control systems require sensing and feedback of a number of variables such as motor winding current and voltage, dc bus voltage and current, and motor position and velocity. The measurement technology, measurement variables, and precision requirements of the measurement circuits are very dependent on the complexity and overall architecture of the end application. These factors also have a direct impact on the performance, cost and efficiency of the motor control system. This article by Nicola O'Byrne () addresses in detail the tradeoffs and trends in measurement techniques in motor control.