Patent ID: 8481914

Claim:
An optical encoder comprising: scales; encoder heads which are provided so as to correspond to the scales respectively and which detect relative displacements from the respective scales; a signal processing circuit which processes encoder signals output from the encoder heads; at least one common wiring line which is shared by the encoder heads and which transmits the encoder signals to the signal processing circuit; signal output state switching units which are provided for the encoder heads in a one-to-one correspondence and each of which sets at least one signal output from the corresponding encoder head to the common wiring line in an on state or an off state; and a control unit which specifies one of the encoder heads, sets the signal output of the specified encoder head in an on state, and further sets the signal outputs of the encoder heads not specified in an off state, thereby controlling the signal output state switching units so as to cause only the specified encoder head to output the encoder signal to the signal processing circuit, wherein the encoder heads set in the off state by the corresponding signal output state switching units output a specific voltage value as the encoder signals to the common wiring line.