Canon DADF-R1, Service Manual

Page: 83 / 222

Chapter 3
3-25
3.4.6 Controlling the Separation Motor (M4)
0013-3483
The following is a diagram of the circuit used to control the separation motor (M4). The separation motor is a
DC motor, and the circuit has the following functions:
- turning on/off the motor
- controlling the speed of the motor
- protecting the motor against overcurrent
F-3-30
[1] ADF controller PCB
[2] Current detection circuit
M4: separation motor
MI2: separation motor clock sensor
When the CPU sends the motor rotation speed signal (SPPWM), the separation motor (M4) starts to rotate in a
specific direction. The separation motor clock sensor (PI2) sends the separation motor rotation speed signal
(SPCLK) to IC17 (speed control IC). In response, IC17 compares the arriving rotation speed signal against the
speed reference signal (SEPCLKREF) from the CPU, and sends the result as the speed control signal (SPMFV)
to the CPU. Using the arriving speed control signal, the CPU varies the rotation speed signal. LED3 goes on
when the motor rotation speed is within a specific range, while going off if out of the range. The current
detection circuit monitors the current flowing in the separation motor; when the level of the current exceeds a
specific value, it sends the separation motor stop signal (SPLIM) to stop the motor. The CPU identifies a fault
in the separation motor if the separation motor stop signal continues, indicating an error code (E405) on the host
machine's display.
Error code: E405
- fault in the separation motor (M4)
- fault in the separation clock sensor (PI2)
- fault in the ADF controller PCB
M4
SPLIM
SPPWM
SPCLK
SEPCLKREF
SPMFV
+24R
+5V
J12
J8
PI 2
IC18
CPU
Q28
Q29
LED3
IC16
1
2
5