L WOO Service Manual
Operating Principles
2.3.7 Carriage Motor Driver Circuit
Figure 2-18 shows the carriage motor driver circuit. The carriage motor driver uses an
open-Ioop,
constant-current chopping drive arrangement. The motor is driven with 2-2 phase excitation and
1-2 phase excitation.
The MOO-3 (pins 3-6) on the CPU are used to control the phases of stepping motor. The carriage
motor driver
IC
(IC8)
detects the amount of current
in
the
carnage motor
coils
and regulates the
current. The amount of current flowing in the coils varies, depending on the speed of the carriage
motor. The amount of the
cument
is set by the gate array
(IC2).
Signals are sent to the
ODO-0D2
on the CPU.
ODENO-1
and
OPHO-1
on the CPU control the stepping motor.
Table 2-9. Carriage Motor Drive Modes
Driver
Mode
Excitation Type
Drive Frequency Type
Standard Print Character
3 x speed
2-2 phase
2400
PPS
Draft Mode
2
X
speed
2-2 phase 1600
PPS
Draft Copy Mode
3/2
X
speed
2-2 phase
1200
pps
Bit Image Mode
1
X
speed
1-2 phase
1600
ppS
LQ Mode
3/4 x
speed
1-2 phase
1200
pps
LQ
Copy Mode
1/2 x speed
1-2 phase
800
PPS
LQ
Speed Down Mode
GATE ARRAY
ODEN1
OPH1
ODENO
OPHO
OD2
OD1
ODO
IC2)
+5V
+5V
H
CR Motor
Driver
IC
(
OA
O-A
00
o-B
46
72
B2
n
;8)
CR MOTOR
T
CRA
.
10
CR_A
CRB
15
CR_B
Vx
Vx
3
‘IIIJ
t-
CRCOM
Jr
Figure 2-18. Carriage Motor Driver Circuit Diagram
Rev.A
2-15
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