Position encoders are widely used in motion control applications and many different types are available. To choose the optimum device for a given application, engineers must decide between absolute, incremental or commutation encoders, which present data in various formats such as quadrature, motor-pole or a serial protocol. The resolution required, as well as dimensions and mounting type, also need to be considered.
In addition, the choice of output circuit topology influences aspects of system performance such as power consumption, speed range and noise immunity. Many encoders have open-collector outputs, which can simplify interfacing with other devices, particularly if voltage-level shifting is required. On the other hand, external pull-up resistors must be added, which increase power consumption and limit the output slew rate.
Fortunately, other configurations are available that allow engineers to overcome these disadvantages and deal effectively with other issues such as noise and interference.
This CUI Devices’ blog, A Comparison of Common Encoder Output Signals by Jason Kelly, Motion Control Design and Applications Engineer at CUI, explains the inner workings of encoder output circuitry to help engineers choose the optimal encoder for each application.