Carriage Motordrivecircuit; Figure 2-21. Carriage Motor Circuit Block Diagram; Table 2-8. Serial Data Contents - Epson 4003353 Service Manual

Sty/us Color service Manual
Carriage Motor Drive Circuit
2.3.2.3
The motor drive IC SLA7041MS (IC15) outputs a constant current to drive the carriage
carriage
motor for the printer mechanism. Gate array E05A96EA (IC2) decides the motor phase
and then sends a signal to the carriage motor driver IC (SLA7041MS) using the 4-bit serial
transmission line.
The first bit indicates the direction of the motor rotation. The other three bits are current duty data
for the motor speed of each printing sequence. SLA7041MS can select the reference voltage itself
based on these three current duty data. Also, it receives these signals by 2 serial transmission lines
for 2 motor's phases (phase A and phase B). Due to this, the carriage motor can drive the miao step
sequence (min. 1/720 inches).
CRHLD

Figure 2-21. Carriage Motor Circuit Block Diagram

The 4-bit serial data is read by the SLA7041MS motor driver by 4 clock counts from the E05A%
data is set into the shift register and then shifts the latch register. When the strobe pulse becomes
active from the E05A96 (IC2), the serial data is moved into the reference voltage selection circuit
and the voltage is changed. Therefore, when the printer is in the constant speed mode, this strobe
pulse becomes inactive. The following table indicates the current duty of each carriage motor speed
mode.
Mode
Rev. A
28
.
6
27
17
25
3
—
B
NPN Tr

Table 2-8. Serial Data Contents

c
I
2
0 1 0
3 0 1 1
4 1 0 0
I
7
' CLKB
—
A
11
18
9
E
I
Vref
x 20?/$0
x
Vref x 1/3
(Vref = +5V) x 55.5?/0
x 71.470
x
I I
Operating Principles
and speed
1
8 2
3
4
>
5
+ 4
40
100%
2-17