The HEIDENHAIN RE‑21‑1‑K23 (ID 5906193‑01) is an industrial resolver used for precise rotational position feedback in servo motors and motion control systems. It converts the angular position of a rotating shaft into analog sine and cosine signals, enabling controllers and drives to accurately determine rotor position and speed. The resolver belongs to the RE-21 series, which is known for its robust construction and reliable performance in demanding environments. Typical specifications for this series include operation with an excitation voltage of about 7 V at several kHz, permissible speeds up to 20,000 rpm, and a wide operating temperature range from -55 °C to +155 °C. These resolvers are commonly used in CNC machines, robotics, and industrial automation systems requiring durable and precise position measurement.