Carriage Motor Drive Circuit - Epson LQ-1170 Service Manual

Carriage Motor Drive Circuit

2.3.4
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.
Drive Mode
10/3
X speed
3 X speed
8/3 X speed
2 X speed
1.5 X speed
4/3 X speed
1 X speed
3/4 X speed
2/3 X speed
0.5 X speed
Po
Data
PI
Bus
P2
Figure 2-22. Carriage Motor Drive Circuit
Table 2-6. Carriage Motor Drive Modes
Excitation
2-2 phase
2-2 phase
2-2 phase
2-2 phase
1-2 phase
1-2 phase
1-2 phase
1-2 phase
1-2 phase
1-2 phase
'RAIN
CRBIN
CR-A
CR-B CR-B
-HOLD
- L
- M
Driva Fraquency
3 5 9 3 pps
3300 pps
2932
2 2 0 2 pps
1 6 5 1 PPS
1 4 6 3 PPS
1 1 0 1 pps
8 2 5 PPS
7 3 3 pps
5 5 0 pps
2 - 1 9
CR Motor
+ Coil Current
Gp
GND
Standard Characters Printed
High Speed Draft
Draft
Draft
High Speed Japanese Kanji
LQ, Japanese Kanji
REV.-A