Toshiba 4560, Service Manual

Page: 61 / 369

4560/4570 DRIVE 6 - 6 Nov. 1997 © TOSHIBA
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(F-MOT-REF)
PLL-OK
CW/CCW
MOT-BRK
MOT-ON
6.4 Main Motor, Transport Motor
6.4.1 Motor drive
Difference
Speed
comparator
Rotation
control
Difference
Voltage
detection
circuit
Excitation
phase
switching
section
Rotor
position
detection
Phase
comparator
Hall element A
FG pulse
Phase W
Phase V
Phase U
Motor
Control
signal
(1) The LGC transmits control signals for motor rotation.
Main motor: MAIN-CW/CCW: Direction of rotation, MAINMOT-ON: Motor rotation command
Transport motor: FEED-CW/CCW, FEEDMTR-ON
(2) The excited phase switching unit excites each phase on motor Motor runs.
(3) Hall elements A to C are used to detect the rotation position of the motor (or rotor).
(4) The excited phase switching unit switches the excitation for each phase.
(By repeating (2) through (4) above, the motor keeps running.)
(5) The FG pulse is generated by the FG pulse pattern and the N/S magnets of the rotor installed on the
motor.
(6) The phases and velocities of the FG pulse and the reference frequency from the LGC are compared
and the differences are added to IC3. Further to this are added the fluctuations in the supply volt-
age. (Signal generation)
(7) Changes the switching timing for the excited phase switching unit to match the signal amount ob-
tained in step (6).
In other words, control is performed to equalize the FG pulse and reference frequency. The motor
runs at a constant speed. (Locked range state.)
(8) When the motor enters the locked range state, the excited phase switching unit transmits the PLL-
OK signal to the LGC. (“L” level).
(9) When the MOT-BRK from LGC enters “L” level, the motor rotation is braked, and when the MOT-ON
signal enters “H” level, the main motor stops.
Hall element C
Wave
shaping
Photo-
interruptor
Hall
element B
Reference frequency
Lock
protection
circuit