Patent ID: 8546743
Filing Date: 2013-10-01
Classification: G01D

Abstract:
1. An encoder designed to detect a relative displacement between an encoder scale and an encoder head, the encoder head incorporating a light source, a light-receiving element configured to receive light from the light source via the encoder scale and a signal-processing unit configured to process an electrical signal output from the light-receiving element, the encoder comprising: a signal detection unit configured to be activated independently from an operation of the encoder in accordance with setting, and to detect, when activated independently from the operation of the encoder, one or more electrical signals output from the encoder head; a signal discrimination unit configured to be activated independently from the operation of the encoder in accordance with setting, and to determine, when activated independently from the operation of the encoder, a waveform of the encoder signal detected by the signal detection unit; and a switching unit configured to switch a current supplied to the light source to one of various magnitudes in accordance with the waveform determined by the signal discrimination unit.