To enable measurement of linear guiding and thermal drift errors during movement of a stage or machine, Heidenhain Corp. has unveiled the 1Dplus encoders. The 2-D encoders can be used in stacked stages, precise gantries, wafer processing, and in large flat panel display production and testing. They are frictionless and have gratings in two dimensions. Models featuring two or three scanning units for simultaneous measurement of the X and Y directions are available. Three units enable calculation of the angle of rotation of the bracket that houses them.