T H E P E N Instructions, Pu A N D Pd; The Select Pen Instruction, S P; T H E V E L O C I T S E L E C T Instruction, V S - HP 7470A Interfacing And Programming Manual

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'he Pen Instructions, P U and P D
The pen up instruction, PU, and the pen down instruc­
tion, PD, raise and lower the pen.
HKiyi The instructions are used to raise and lower the pen during
plotting. They may be used with parameters to plot or move to the
points specified by the parameters.
E Q M E I PU (terminator)
or
PD (terminator)
and
PU X,Y(,...)(terminator)
or
PD X,Y(,...)(terminator)
When no parameters are included, the pen up instruc­
tion, PU, raises the pen without moving it to a new location. The pen
down instruction, PD, lowers the pen without moving it to a new
location, if the pen is within the window. If parameters are included,
the pen will move, in order, to the X,Y coordinates specified. The coor­
dinates are interpreted as plotter units if scaling is off and user units if
scaling is on. Moves are either relative or absolute, depending on
whether a PA or PR was the last plot command executed.
If parameters are included, both coordinates of an X,Y coordinate pair
must be given. An odd number of parameters will set an error condi­
tion, but all X,Y pairs which precede the unmatched parameter will be
plotted. For a description of the PU and PD commands with parameters,
refer to The Plot Absolute Instruction, PA, and The Plot Relative
Instruction, PR, which follow.
NOTE: The plotter has an automatic pen lift feature which will lift the
pen after it has been in the pen-down state for 55 seconds and no pen-
down plot commands or label commands have been sent to the plotter
or no front-panel pen-down moves have been made for 55 seconds. ■
^he Select Pen Instruction, SP
The select pen instruction, SP, selects and/or stores one
of the two pens.
IIKlM The instruction is used to load a pen into the pen holder so
that drawing will occur. It can be used to select a pen of a different
color or width, during the plotting program. It can be used with a zero
parameter or no parameter to store the pen currently in the pen holder
into its stall at the end of a program.
2 CONTROLLING THE PEN AND PLOTTING
mum SP pen number (terminator)
or
SP (terminator)
ED3EEEQECI The pen parameter must be in the range of -32 768 to
32 767. Decimal fractions are truncated. An odd-numbered parameter
selects the pen from the left stall; a n even-numbered parameter selects
the pen from the right stall. A zero parameter or no parameter stores
the pen. When a pen parameter is less than —32 768 or greater t h a n
32 767, an error is generated and the pen does not change.
The Velocity Select Instruction, VS
The velocity select instruction, VS, specifies the pen-
down speed for plotting and labeling operations.
BH33
The instruction is used to set velocity to a speed other than the
default velocity of 38.1 cm/s and to change the acceleration from its
default value of 2 g (980 cm/s
2
). This instruction should be used to slow
velocity to 10 cm/s when plotting on transparency film. A slightly
thicker line can be created by slowing down the pen speed on any
medium. A pen nearing the end of its life will write with a clearer,
sharper, more solid line if the velocity is slowed.
Bum VS pen velocity (terminator)
or
VS (terminator)
A VS command without parameters sets pen velocity
to its default velocity of 38.1 cm/s (15 in./s) and acceleration to 2 g (980
cm/s
2
). A VS command with parameters sets the pen velocity for hori­
zontal or vertical pen-down moves to the value specified by the first
parameter and slows the acceleration to 0.5 g. Anything after the first
parameter is ignored. Parameters must be in the range 0 to 127.9999. A
velocity of 0 is set to 0.38 cm/s. Velocity can be set in increments of 0.38
cm/s. Parameters are rounded to the nearest multiple of 0.38 c m / s .
Negative parameters and parameters greater than or equal to 97 set a n
error condition (error 3) and the velocity does not change. Parameters
between 38.1 and 96 set velocity to its default value of 38.1 cm/s.
When either the horizontal or vertical velocity falls in the range 0.38 to
3.8 cm/s, it is reset to a slower or faster velocity to avoid this range.
This is done to assure lines of high quality. The change is most notice­
able when a line is almost vertical or almost horizontal. Pen-down
moves will be at the specified velocity except when such adjustment is
necessary.
Execution of a VS command with a parameter of 38.1 will slow t h e
acceleration, giving the highest line quality at that maximum speed.
CONTROLLING THE PEN AND PLOTTING 3-3