Motor, Cr Drive Circuit - Epson LQ-1070 Service Manual

2.3.4

MOTOR, CR Drive Circuit

Figure 2-22 shows the MOTOR, CR drive circuit. An open-loop, constant-current drive arrangement is
used for running the MOTOR, CR. The motor is driven by 2-2 phase excitation and 1-2 phase excitation.
2-2 phase excitation corresponds to two 1-2 phase excitation steps. Thus, for each single step phase
2-2
change of a phase excitation motor, the carriage moves 1/1 20 inch. For each single step phase
change of a 1-2 phase excitation motor, the carriage moves 1/240 inch.
The MOTOR, CR drive circuit of the STK-6022B detects the amount of current flowing in the MOTOR,
CR coil and regulates this current. The current flowing through the coil varies, depending on the speed
of the MOTOR, CR. The amount of current is set by the CPU via the E05A50 1/0 port. Signals are sent
to SELR 1 to SELR4 on the STK-6022B. The STK-6022B sets the coil current to correspond to the
MOTOR, CR speed.
Ports P60 to P63 on the CPU are used exclusively as control ports
CPU (lC)
P61
I
Drive Mode
3.214 X speed
3 X speed
2 X speed
1.5 speed
X
4/3 X speed
1 X speed
2/3 X speed
1/2 X sDeed
Po
Data
Bus
P2
P5
E05A50(4D)
Figure 2-22. MOTOR, CR Drive Circuit
Table 2.6. MOTOR, CR Drive Modes
Excitation Tvoe
2-2 phase
2-2 phase
2-2 phase
1-2 phase
1-2 phase
1-2 phase
1-2 phase
1-2 phase
CRC
m
2700
2520
1 6 8 0
2520
2240
1 6 8 0
1120 pps
840
2-17
for the stepping motor.
MOTOR, CR
Coil Current
Gp
1
GND
Standard Print Character
High Speed Draft
Draft
LQ
REV.-B
I