Linear encoders sense and digitize linear position change for positional measurement and feedback to control systems. Travel, encoder resolution, encoder accuracy, and lines or counts per distance are the most important performance specifications to consider. Travel or measurement range is the full range of travel that can be encoded. Some linear encoders have selectable or configurable measurement ranges. Encoder resolution is the smallest degree of distance measurement that linear encoders can make. Typically, this specification is set to different values within the same linear encoder. Encoder accuracy is a performance specification that accounts for variables such as linearity, hysteresis and temperature. Lines or counts per distance determines the minimum linear position increment that can be distinguished. Either counts or lines may be specified, but they are not the same; for example, in quadrature systems, a line is associated with four counts or pulses.