Controlling The Speed - Oce 3121 Technical & Service Manual

3 Controlling the Speed

Motor M1 is a DC motor with an integrated clock pulse generator.
This generates clock pulses (MMCLK signal) in relation to the rotation of the
motor.
The phases of these clock pulses are compared to the phases of a reference sig-
nal, and are controlled until they match. This matching controls the current to
the motor, and maintains the rpm of the motor at a fixed level.
The condition in which the phase of the clock pulses generated by the motor
and the phase of the reference pulses match is called "locking," in which the
constant speed state signal (MLCK=1) is sent to the DC controller PCB. If a
discrepancy occurs in the revolution for some reason, MLCK will go '0'.
If MLCK remains '0' for about 3 sec, a main motor error is detected, causing
all operations to stop. ('E010' will be indicated on the control panel.)
Composite power supply
DC controller PCB
502 TSM Océ 3121
PCB
+24V
0V
MMD
J114-B6
MLCK*
J114-B7
Main motor driver PCB
Drive
circuit
Control
circuit
Hall IC output
Output pulse
Reference signal
Drive
current
Main
motor
(M1)
Functional description
Encoder