Encoder - Kodak DirectView CR 825 Theory Manual

THEORY GUIDE
10DEC05

ENCODER

TG4825-1
Page
77 of 120
ENCODER WHEEL
( 5000 Lines )
The ENCODER monitors the speed and position of the MAGNET in during rotation to provide
smooth operation and continual speed.
Component
ENCODER WHEEL
2 OPTICAL
SENSORS -
EMITTER/
DETECTORS
The signals of the SENSORS are 90 degrees out of phase with each other in a "quadrature
relationship." One DETECTOR detects the edge of a line and the other detects the middle of
the line.
The ENCODER determines:
• speed of the SLOW SCAN MOTOR by measuring the frequency of the signals
• direction of rotation of the SLOW SCAN MOTOR by determining the sequence in which
the signals change
LIGHT EMITTER LIGHT EMITTER
LIGHT DETECTOR 1 LIGHT DETECTOR 2
A clear disk that has 5000 lines leading from the center to the
outside edge.
Placed at the edge of the ENCODER WHEEL. Each beam from the
EMITTER/DETECTOR is blocked by the lines of the WHEEL when
the WHEEL rotates.
Signal from DETECTOR 1
Signal from DETECTOR 2
Description
Scan/Erase
H194_5031BC