Encoder, servo motor, servo system, and encoder control method

A method of controlling an encoder, comprising:

• providing the encoder including:
• an angular position information detector configured to detect angular position information indicating an angular position of a rotating disk within one rotation thereof;
• a multi-rotation information detector including an MR element and configured to detect multi-rotation information indicating a number of rotations of a disk;
• an all-solid state battery including a solid electrolyte and configured to supply a power to the multi-rotation information detector when an external power is not supplied to the encoder;
• a connector configured to connect a connection terminal of the all-solid state battery to a substrate to which at least one of the angular position information detector and the multi-rotation information detector is connected, via a solder in contact with the connection terminal;
• a first magnet serving as a multi-rotation magnet and of which magnetic flux being detected by the multi-rotation information detector;
• an electric signal generator configured to generate an electric signal that serves as a trigger for supplying the power of the all-solid-state battery to the multi-rotation information detector based on the rotation of the disk;
• and
• a second magnet different from the first magnet, serving as a trigger magnet, and of which magnetic flux is detected by the electric signal generator,
• causing a control processor to enter a sleep mode by the power from the all-solid state battery when a supply of the external power is stopped;
• stopping the supply of the power of the all-solid state battery to the multi-rotation information detector when the control processor enters the sleep mode;
• receiving an electric signal generated in response to a rotation of the disk, thereby causing the control processor to be restored from the sleep mode;
• and
• starting the supply of the power to the multi-rotation information detector when the control processor is restored from the sleep mode.