HP 8530A, Руководство по эксплуатации и программированию, Страница: 355 / 439

Programming Examples
Example 14: Plot to User Display Using B ASIC HP-GL
This example draws a simple graphic on the receiver User display using HP B ASIC graphics
instructions . Optionally the graphic may be sent to a plotter on the receiver system bus .
V ector diagrams and T ext can be written to a reserved area of the receiver display memory via
the receiver System Bus using either an HP-GL subset internal to the receiver , or the standard
computer language graphics commands . This reserved graphics area is output using PLOTALL;
and may be recorded and subsequently reloaded into user display memory using the Disc
command USED; .
V ector Diagrams
A vector diagram consists of a PA , Plot Absolute , display instruction followed by any number of
x,y integer pairs .
OUTPUT Rec;"ADDRPASS 31"
OUTPUT Rec_systbus;"CS; PU"
OUTPUT Rec_systbus;"PA 128,384; PD; PA 3328,384, 3328,3584,
128,3584 128,384"
ADDRP ASS 31 sets up the P ass-Thru mode in which data sent to the 8530 System Bus address ,
717, is routed to the User Display area of the receiver display memory . The CS instruction
clears the screen. The PU instruction lifts the pen, causing the following PA instruction to draw
a blank vector . The PD , P en Down, causes the following PA instruction to draw a visible line .
The PA , Plot Absolute , instruction is followed by the coordinates for the other three corners of
the box.
The plotting area of the receiver display is:
x = 0 to 5377, y = 0 to 4095
Figure 18-3 shows internal scaling for P A vector diagrams .
Figure 18-3. P A V ector Scaling
The PR , Plot Relative , instruction moves the pen from its present position to the new position
x,y units away .
OUTPUT Rec;"ADDRPASS 31"
OUTPUT Rec_systbus;"CS; PU"
OUTPUT Rec_systbus;"PA 128,384; PD; PR 3200,0, 0,3200,
18-26 HP-IB Programming