Industrial motion control covers a breadth of applications, ranging from inverter-based fan or pump control, to factory automation with more complex ac drive control, to advanced automation applications such as robotics with sophisticated servo control. These systems require sensing of a number of variables such as motor-winding current or voltage, dc link current or voltage, rotor position, and speed. The selection of variables and the required measurement precision depend on the end application demands, the system architecture, target system cost, or system complexity. There are other considerations, such as value-add features like condition monitoring. With motors reportedly consuming 40% of worldwide electric power, international regulations have increased the focus on system efficiency across the entire range of industrial motion applications. This article by Nicola O'Byrne () in Electronic Products discusses how the use of sigma-delta modulators can improve motion control system efficiency.