Installation manual

Danaher Motion Kollmorgen 08/04 Appendix B
SERVOSTAR S Installation M-SS-001-01 Rev. T 95
APPENDIX B
B.1 Digital Incremental Encoder Types
The SERVOSTAR products include models designed for use with
incremental digital encoders. Encoders are available in different
configurations from a variety of manufacturers using different
nomenclature and conventions, making this topic somewhat
confusing. Encoders can be as simple as having only A and B
output channels or as complex as 6 channels of outputs. The
SERVO
STAR supports many of these variants using the variable,
MENCTYPE. The variable is set according to the features of the
encoder. This document explains the different applications of the
various MENCTYPEs. A basic understanding of encoders is
valuable for this discussion.
B.1.1 ENCODER BASICS: A REVIEW
Encoders used with the SERVOSTAR provide incremental motor
position information via two channels, referred to as the A Channel
and B Channel. These channels output pulses for a unit of shaft
motion. These pulses are typically generated within the encoder,
using an optical disk that is directly connected to the motor shaft.
The disk has etchings that either transmit or block light passing
through the disk. An optical transmitter and receiver are on either
side of the disk. The rotation of the disc (and motor shaft) interrupts
light transmission from source to receiver, creating the pulses. The
interruptions on the disk are called lines and result in the encoder
ratings of lines-per-revolution (LPR) or pulses-per-revolution (PPR).
The two channels provide the same information (pulses-per-unit of
motion), but have a phase shift of 90º between each other as
shown in the figure below.