LX-105O+ Service Manual
Operating Principles
2.3.2.2
Sensor Circuit
Following figure shows the sensor circuit in block diagram. The
PAO
of CPU port senses carriage
home position. The
PA1
senses paper end. The
PA2
senses release lever position. The
AN5
of CPU
A/D convertor senses
+24V
line voltage.
HOME
PE
RELEASE
+24V
line
CPU
PAO
uPD7810HG
(2C)
PA1
PM
AN5
Figure 2-14. Sensor Circuit
2.3.2.3
Carriage Motor Drive
Following figure shows a block diagram of the carriage motor drive circuit. In this circuit, the phase
switching for the carnage motor is directly executed not by the CPU, but by the gate array
(3B),
which acts on the basis of the CPU phase data. SLA7020M drives the carriage motor with a
stabilized stabilized current.
The excitation system is determined by the firmware and is executed in accordance with the
carriage speed, as shown in Table 2-4.
CPU
L
PD78 10HG
(2 c)
GA
E05A30
(3B)
b
Phaseā€¯ Data
1
SLA
7020M
( 1A)
Figure 2-15. Carriage Drive Circuit Block Diagram
Table 2-4. Phase-Excitation Method
Drive Mode Excitation Type Drive Frequency Type
Mode 1
2-2
phase
1200
pps
Mode 2 2-2 phase 900
pps
Mode 3 1-2 phase
1200
pps

I

Mode
41-2
phase 900
pps
o

M

Rev. A
2-11