CAPACITIVE ANGLE ENCODER AND WITHDRAWABLE FEEDER FOR CIRCUIT BOARD COMPONENT INSERTION MACHINES

摘要

The invention relates to a capacitive angle encoder for detecting a rotational position of a rotatable object relative to a stationary object as well as a withdrawable feeder for circuit board component insertion machines, said withdrawable feeder being equipped with an angle encoder according to the invention. The angle encoder comprises a stator that supports first and second transmitting electrodes and first and second receiving electrodes, and a rotor which supports an incremental coupling electrode and an absolute value-coupling electrode. The incremental coupling electrode is designed such that the first electrostatic field is modulated by a change in capacitance in response to a change in the rotational position of the rotor, while the absolute value-coupling electrode is designed such that the second electrostatic field is modulated by a change in capacitance in response to an absolute rotational position of the rotor. A signal processing circuit detects the first and second modulated electrostatic field and determines a measured value for the position in response to the detected field. The at least one first and second transmitting electrode and the at least one first and second receiving electrode are coplanar to one another.