Section II
Before applying power
to
the plotter,
check the line voltage selection (visible
through the small window
in
the rear
panel)
and
make sure the selected line
voltage
and
fuse value are correct.
If
not, refer to Line Voltage and Fuse
Selection
in
Section I.
b. Apply power to the plotter.
c.
With the PAPER LOAD lever
in
the LOAD posi-
tion, place a sheet of paper (ISO
A4/
8-112
X
11
in. or ISO
Aa/
11
X
17
in.)
against
the left-hand
rail
and
the rear guide. Lower the lever to the
PAPER
HOW
position
and
be sure
that
the
plotter is set for the proper paper size.
d.
Select a pen by pressing one of the six pen push-
buttons
and
then operate each of the front-panel
controls. Vertical, horizontal,
and
diagonal lines
(using the directional controls with a pen down)
should
be
smooth.
NOTE
If
the pen is down,
it
will lift when
either
Pl
or P2 is pressed. The VIEW
pushbutton is a latching control. After
VIEW is pressed
once,
the other controls
will not operate until VIEW
is
pressed
a second time. The ERROR light should
be on when
in
the VIEW mode. The
ERROR light should be on when the
PAPER lever
is
in
the LOAD position.
If
Pl
or P2
is
pressed while the lever
is
in
LOAD, the ERROR light should
flash. This error may be cleared by
moving the lever to HOLD
and
back
to LOAD,
or
by pressing ENTER
and
VIEW
at
the same time,
in
which case
the plotter initializes again. While the
plotter is ON,
and
the PAPER lever is
in
the HOLD position, the ERROR
light flashes very briefly approximately
every five seconds when the motor
power supply voltage is sensed.
2-15. HEWLETT-PACKARD GRAPHICS
LANGUAGE
2-16.
The Model
7475A
recognizes the Hewlett-Packard
Graphic Language
(HP-GL)
instructions listed
in
Table
2-2.
2-2
Model 7475A
2-17. DEMONSTRATION PLOT
2-18.
The Model
7475A
contains a demonstration plot
stored
in
Read Only Memory
(ROM).
The running of
this plot will verify proper operation of most of the logic
circuits
as
well
as
the operation of the paper
and
pen
drive mechanisms; however,
it
does not test the
1/0
circuitry.
To
run
the demonstration plot proceed as
follows:
a. Make sure six pens are installed
in
carousel.
b.
With the PAPER LOAD lever
in
the LOAD posi-
tion, place a sheet of paper (A4/ 8-1/2 X
11
in. only)
against
the left
hand
rail
and
the rear guide.
Lower the lever to the paper
HOW
position.
c.
While holding down buttons
Pl
and
P2, apply
power
to
the plotter.
See
Figure
2-1.
Release buttons
after initialization starts.
d.
The resultant plot
is
illustrated in
Figure
2-2.
2-19. TEST PROGRAM
2-20.
The program in Figure
2-3
is
written
in
BASIC
language specifically for the
HP
Model
85
Personal
Computer, but may be adapted to other controllers. This
program tests the input/output circuits
of
the 7475A
and
the majority of the logic circuits,
as
well
as
the operation
of the paper
and
pen drive mechanisms. The resultant
plot is illustrated
in
Figure
2-4.
NOTE
Lines beginning with
an
exclamation
point are only explanatory and not
part
of the plot program. Those lines may be
omitted when entering the program.
The addresses shown
in
lines
130,
and
140
are only examples,
and
may vary
with the system or computer used.
2-21. REPEATABILITY
2-22.
To verify repeatability specification (Table
1-1)
load six new pens
in
the carousel
and
run
the test
program previously described. Using
an
optical com-
parator, verify
that
the repeatability points on the test
plot are within
0.1
mm
using the same pen,
and
within
0.2
mm
using a different pen. See Figure
2-5.
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