Sealed linear encoders are protected from dust, chips and splash fluids and are ideal for operation on machine tools.
Exposed linear encoders operate with no mechanical contact between the scanning head and the scale or scale tape. Typical areas of application for these encoders include measuring machines, comparators and other precision devices in linear metrology, as well as production and measuring equipment, for example in the semiconductor industry.
With incremental linear encoders, the current position is determined by starting at a datum and counting measuring steps, or by subdividing and counting signal periods. Incremental encoders from HEIDENHAIN feature reference marks, which must be scanned after switch-on to reestablish the datum. This process is especially simple and fast with distance-coded reference marks.
Absolute linear encoders require no previous traverse to provide the current position value. The encoder transmits the absolute value through the EnDat interface or another serial interface.