Canon PC980 Service Manual - Page 208

CHAPTER 8 ADF B Basic Construction 1. Outline of the Electric Circuitry The ADF's major electrical mechanisms are controlled by the CPU on the ADF controller PCB. The CPU on the ADF controller PCB reads the signals from the sensors and the copier and generates signals to drive the motor at such times as programmed in advance. The copying modes selected on the copier are communicated to the ADF in serial, and the ADF communicates to the copier the state of feeding originals to the copier in serial. (It does not use an IC for communications.) [Input block] [Control block] [Output block] Sensor Switch ADFcontroller PCB CPU (Q1) ROM (Q2) 24V 5V Motor Serial communication Copier Composite power supply PCB Figure 8-102 8-2 COPYRIGHT © 1999 CANON INC. CANON PC800s/900s REV.0 AUG. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)