Home Position Seek - Epson LX-HOO Technical Manual

REV.-A

2.4.5.3 Home Position Seek

Figure 2-21 shows the home position seek operation (actual carriage movement)
Held for 20 to 30 ms
according to the phase
data combination.
I
Moves from left to right for
four steps, then stops.
I
A home position seek is performed when the hardware is initialized. Because the carriage control is
an open-loop system, the CPU must perform a home position seek in order to get the carriage to a known
reference position. This operation is performed at 450 PPS (l-1 phase drive). The printing start position
(column 1) is 25 steps to the right of the home position. The carriage does not return to the home position
unless the printer power is turned off. When the carriage motor is in the acceleration mode or the normal
printing mode, the CPU checks the home position signal every time the phase is switched. If the CPU
detects that the carriage is at the home position, it regards this as a carriage error.
N
1
Moves from right to left for
four steps, then stops.
Moves from right to left until
it reaches the home position.
I
I
Decelerates for five steps,
then stops.
Fig. 2-21 Home Position Seek Operation Flow
Q
Moves from left to right until
it leaves the home position.
Is this the
home position?
Decelerates for five steps,
then stops.
I
2-26
1
N ,
I
N
Moves from right to left with
a step time intewal of 10 ms
until it reaches the home
position.
I