Ricoh FT6645 Manual page 63

OPTICS
3.7 OPTICS CONTROL CIRCUIT
Main
Control
Board
Main
CPU
Exposure Lamp
The optic control board communicates with the main board through a data
bus. The optics control board monitors all the sensor signals, encoder output,
thermistor output and controls all motors in the optics.
At the programmed time, the main CPU sends a scanner start signal to the
optics control CPU.
The CPU generates a pulse-width modulation (PWM) signal. The PWM
signal goes to a driver circuit, which sends drive pulses to the scanner drive
motor.
An encoder in the scanner drive motor generates pulse signals.
A speed/direction control circuit monitors the scanner speed and the direction
of the signals, and uses this data to regulate the motor speed.
The home position sensor monitors the position of the scanner. When the
main switch is turned on, the main CPU confirms the position of the scanner
by moving the scanner out of the home position and back again. This data is
sent to the optics control CPU.
Sensors
Data
Bus
Optics Control Board
Optics Control
AC Drive
Board
CPU
Optic Thermistor
2-38
23 April 1993
Encoder
E
Scanner Drive
M
Horizontal Lens
M
Drive
Vertical Lens
M
Drive
3rd Scanner
M
Drive
Optic Cooling
M
Fan