Controlling The Pickup Motor; Outline - Canon DADF-G1 Service Manual

2.7 Controlling the Pickup Motor

2.7.1 Outline

The following figure shows an outline of the circuit used to control the pickup motor:
The feed motor is a DC motor.
The microprocessor (Q1) on the DADF controller PCB sends to the drive circuit the
pickup motor drive signal (SMON), pickup motor rotation direction signal (SDIR), and
pickup motor rotation speed control signal (SMPWM).
The drive circuit drives the pickup motor in response to the incoming three types of sig-
nals.
The control circuit is not equipped with a circuit designed to communicate the state of ro-
tation of the pickup motor back to the microprocessor (Q1) as feedback. Since the pickup
motor rotation speed control signal (SMPWM) remains a specific level at all times, no cor-
rection will be made even when changes occur in the speed of rotation of the pickup motor
as a result of external forces.
Q1
CPU
COPYRIGHT© 2000 CANON INC.
DADF controller PCB
SMON
Drive
SDIR
circuit
SMPWM
F02-207-01
CANON DADF-G1 REV.0 OCT. 2000
CHAPTER 2 OPERATIONS AND TIMING
Pickup motor
J12-1
J12-2
M1
2-25