Preparing Your Plotter For Use As A Digitizer; The Digitize Point Instruction, Dp; The Digitize Clear Instruction, Dc; The Output Digitized Point And Pen Status Instruction, Od - HP 7470A Interfacing And Programming Manual

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preparing Your Plotter for U s e
^ys a Digitizer
A plotter with an HP-IB interface must be set to an address less than
31 because the plotter cannot send the coordinates of a digitized point
) to the computer when it is in listen-only mode.
Use of a digitizing sight, available as an accessory with the 7470, is
recommended. The sight should be loaded manually into the pen holder
itself. It may be inserted into the pen holder from either side. Place the
flange on the digitizing sight on top of the arm of the pen holder. The
top of the sight will just clear the top of the pen holder. Push the sight
gently into the pen holder; it will snap into place.
CAUTION
The sight should not be stored in a pen stall; do not
store using front panel buttons or an SP command.
Remove the sight from the pen holder before raising the
PAPER LOAD lever since the sight would be stored auto­
matically when the lever is raised.
To remove the sight from the pen holder, pull either arm of the pen
holder forward and push the sight out of the pen holder.
The sight is used in the pen down position.
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Loading the Sight Unloading the Sight
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The Digitize Point Instruction, DP
The digitize point instruction, DP, provides the means
s to digitize points on the plotter.
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H M K I
This instruction can be used to input data for a graphics pro-
v. ) gram or obtain the coordinates of a point or points on the plot.
6-2 DIGITIZING
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DP (terminator)
EXPLANATION
No parameters are used. The instruction will execute
even if no terminator is received.
When the DP command is received, automatic pen lift is suppressed
and the plotter is ready to have a digitized point entered by pressing
ENTER on the front panel.
When
ENTER
is pressed, the X- and Y-coordinates of that point and pen
up/down status are stored for retrieval by the OD command. Pressing
ENTER
sets bit position 2 of the status byte, indicating a digitized point
is available for output.
After
ENTER
has been pressed, automatic pen lift is reactivated.
The Digitize Clear Instruction, DC
DESCRIPTION
The digitize clear instruction, DC, provides a means to
terminate digitize mode.
F F l T l This instruction can be used to terminate digitize mode with­
out entering a point. If you are using a n interrupt routine in a digitiz­
ing program to branch to some other plotting function, you could use
DC to clear digitize mode immediately after branching.
E Q M Q DC (terminator)
No parameters are used. The instruction will execute
even if no terminator is received.
When the DC command is received, digitize mode is terminated. Auto­
matic pen lift is reactivated.
The Output Digitized Point and
Pen Status Instruction, OD
The output digitized point and pen status instruction,
OD, is used to output the X- and Y-coordinates and pen up/down status
associated with the last digitized point.
I'KlTl This instruction is used after DP and ENTER in all digitizing
applications to return the coordinates of the digitized point to the
computer.
E f f i E E l OD (terminator)
I ? n l "in fill I
1
h i No parameters are used. The instruction will execute
even if no terminator is received.
DIGITIZING 6-3
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