Introduction To The Plotter Coordinate System - HP 7475a Operation And Interconnection Manual

statements, or you
and sends to the plotter as HP-GL instructions. The Interfacing and
Manual contains complete infonnation about handshak·
Programming
ing and programming in HP·GL.
Introduction to the Plotter Coordinate
System
The plotter area is that area of the paper in which the pen can draw.
This area should be thought of as a two-dimensional Cartesian coordi·
nate system. In this system, the entire plotting area is divided (scaled)
into a grid as shown in the following illustration. Each intersection of
these grid lines represents a distinct point that is expressed by X-and
Y·axis coordinates with respect
example, the coordinates X
section of the fourth positive grid line along the X-axis and the fifth
positive grid line along the Y·axis. These coordinate values are used as
parameters in HP-GL instructions to move the pen to any given point
in the plotting area.
Grid spacing (resolution) can be in either plotter units, which have a
fixed length, or user units, which are variable in length. A plotter unit
is 0 . 02488 mm ( 0 . 000
ter can make. The maximum numeric range that the plotter under·
stands is
-32768 to
+32767
•
•
7
6
5
y ·AXIS
4
3
2
OR
I
••
-32768 -2 -1
•
-1
-2
•
•
-32768
2·4
'PLO'ITER OPERATION
can
use AGL statements which the computer encodes
the origin point (X
to
4 and Y
= =
98 in.) in length and is the smallest move the plot­
+32767 for both plotter units and user units.
14,5
4
5
1 2 3
X-AXIS
Cartesian Coordinates
Y
0,
=
5 define the point at the inter­
B 1 0 ' •
9
6 7
0) . For
=
•
+32767