Bearingless angle encoders
February 18, 2008 by Manufacturing AUTOMATION
HEIDENHAIN Corporation has introduced a new series of bearingless angle encoders, the ERP 4080 and the ERP 8080 modular angle encoders. The company recommends the encoders for applications in clean environments, including the electronics industry (wafer positioning), or in the production and testing of storage media (servotrack writing or head testers). The ERPs are able to combine small signal periods with large mounting tolerances because of the incorporation of a new scanning method. This method uses a very small scanning area that is illuminated by a spot laser (VCSEL). The fine grating period of the circular scale diffracts the light which is then collimated in the scanning reticle and brought into interference. The ERP 4080 has an outside diameter of 44 mm, an insider diameter of 8 mm and 131,072 signal periods. The ERP 8080 has an outside diameter of 108 mm, an inside diameter of 50 mm and 360,000 signal periods.