JUKI 6100 Technical Manual page 62

Port
3
:
Configured
as
an asynchronous
special
I/O port for
communications with
the
MCU-1
board.
The 6100
provides
vertical
forms
motion
in
increments of 1/96 of an inch
either
forward
or
backward.
The
timing
diagram
shown
in
Fig.
7.18 represents the
control
and
clock
signals
necessary to
move
the
forms forward one
line at
6LPI.
The
VFG
line
(P2.2)
is
a
gating
signal
which
allows selection
of
either
the
forms
stepper
motor
or the
daisywheel stepper motor.
The
PMEN
line
(P2.1)
is
also
used
as a gating signal to
allow stepper
motion. Port
1
bits
7
and
8
each
generate
a
square
wave
signal,
the
two
signals are
90
degrees
out of phase
and
are
decoded
to
provide four phase pulses to drive the stepper
motor. The
platen
will
move
1
/96th
of an inch
for
each phase change.
Two
of the four phases
are
always
active
and
phase changes occur
as
follows: 3
&
4
active,
4
&
1
active,
1
&
2 active, 2
&
3
active
back
to 3
&
4
active.
Sixteen phase changes
are
needed
to
move
the platen
1
/6th of
an
inch (6LPI),
for
8LPI or l/8th inch of
movement,
12 phase changes
would be needed.
The
time
between phase changes
is
approximately
5
millisecond,
therefore, to
move
the platen
1
/6th inch
would
require
(16x5
msecs) 80
milli-
seconds plus
a
20 millisecond
settling
time. Platen speed
is
approximately
2 inches
per second.
1111111
8901
23456
"
7
1
I
l_
p
'-
8
1
I
L
PH1
i
—
i
r~
PH2
i
1
r
PH3
1
I
L_
1
H4
.
1 i
L
PMEN
1^
VFG
.
Fig.
7.18
The operation of the daisywheel
selection
motor
is
similar
to that
of the forms
motor
with only
a
few exceptions.
Fig.
7.19
illustrates
the control
and
timing
signals for
the
daisywheel
selection
motor.
The
VFG
line
must
be high to enable
the
decoding
circuitry to
produce the four phase
pulses
which
drive the
motor.
The two
square
wave
inputs to the
decoding
circuits
now
come
from
port
1
bits 5
and
6.
The
phase of
these
two
lines
are different
from
that
of
Fig.
7.18.
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59
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