Epson LQ-1170 - Carriage Motor Drive Circuit

REV.-A
2.3.4
Carriage Motor Drive Circuit
Figure 2-22 shows the carriage motor drive circuit. An open-loop, constant-current drive arrangement
runs the carriage motor. 2-2 and 1-2 phase excitation drive the motor. 2-2 phase excitation corresponds
to two 1-2 phase excitation steps. For each single-step phase change of a 2-2 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 carriage motor drive circuit of the
SLA7024M detects and regulates the amount of current flowing
in the carriage motor coil. The current flowing through the coil varies depending on the speed of the
carriage motor. The CPU sets the amount of current via the
E05A49 1/0 port. Signals are sent to HOLD
to -M on the
SLA7024M. The SLA7024M sets the coil current to correspond to the carriage motor speed.
The printer uses ports
P60 to P63 in the CPU exclusively as control ports for the stepping motor.
Po
Data
Bus
PI
P2
SLA7024M (IC 15)
-F
- Coil Current
‘RAIN
CRA CR Motor
CRBIN CRB
m CR-A
CR-B CR-B
-HOLD
-L
-M
Gp
L
+
Coil Current
I GND
E05A49 (4B)
Figure 2-22. Carriage Motor Drive Circuit
Table 2-6. Carriage Motor Drive Modes
Drive Mode
Excitation Driva Fraquency
Standard Characters Printed
10/3
X speed 2-2 phase 3593 pps
High Speed Draft
3 X speed
2-2 phase
3300 pps
Draft
8/3 X speed
2-2 phase
2932
f3f3S Draft
2 X speed 2-2 phase
2202
pps High Speed Japanese Kanji
1.5 X speed
1-2 phase 1651
PPS
4/3 X speed
1-2 phase 1463
PPS
1 X speed
1-2 phase 1101
pps
LQ, Japanese Kanji
3/4 X speed
1-2 phase 825
PPS
2/3 X speed 1-2 phase
733
pps
0.5 X speed
1-2 phase 550
pps
2-19