Absolute position detection within 1 revolution using 3-channel incremental encoders with high resolution track

摘要

The quasi-absolute encoder module determines absolute position within one mechanical rotation. The encoder module includes a three channel position encoder and detection circuitry that includes a read-only memory (ROM). There are three channels: A, B, and I. Channels A and B have four periods and channel B is offset from channel A by 90 DEG in phase. Channel I has a unique sequence. The address generated by sampling this unique sequence corresponds to an address in ROM. The address indicates the position of the rotating shaft on which the code wheel is attached.