The Default Instruction, Df; The Initialize Instruction, In - HP 7470A Interfacing And Programming Manual

£low to Use the Examples in This Manual
The examples in this manual are designed primarily to show the use of
) the instruction with which they appear. New programmers are strongly
A encouraged to enter and run all examples. When the example consists
of only a few HP-GL commands, these commands are listed in quotes.
) No line numbers or BASIC statements are included. The literal string
A listed should be sent to the plotter; the quotation marks only serve to
J delimit the string and are included because many computer languages
~) define literal strings by placing them inside quotation marks. Do not
send the quotation marks to the plotter.
Longer examples are given as programs or program segments in
) BASIC. The programs will run only if the plotter has been defined as
A the system printer. Since the statement to do this is highly system-
dependent, it is not included (except in Chapter 8). Unless specific
) mention is made in the text, the BASIC used is that of the HP-83/85.
You may need to make slight changes in the BASIC statements for
them to run on your computer. You may also need an I/O ROM to
) obtain output from the plotter. Check with the nearest HP dealer or HP
Sales and Support Office. If you are operating in an RS-232-C environ-
) ment, you will need to establish handshaking protocol and include the
\ necessary device control statements in your program.
If you are programming in another language, substitute the output or
input commands of your language for the BASIC statements PRINT
) and ENTER. Change FOR...NEXT loops and replacement statements
(X = 3.14) to whatever statements are comparable in your language. All
) characters enclosed in quotes in the program listing must be sent to the
^ computer using output statements; in addition, some variables, which
are not included in quotes, may need to be sent.
Refer to Chapter 9 for some examples of complete simple programs to
) send and receive information between the plotter and specific com­
puters in an HP-IB environment. The Interconnection Guide (07470-
90003) has some examples of sending HP-GL commands from specific
) computers; there are examples using RS-232-C, HP-IB, and HP-IL
interfaces in that document.
)
)
The Default Instruction, DF
The default instruction, DF, sets certain plotter func­
tions to a predefined state.
l U a x l The instruction can be used to return the plotter to a known
state while maintaining the same settings of PI and P2. This assures
j that unwanted graphics parameters such as character size, slant, or
scaling are not inherited from another program but that the positions
) of Pi and P2 remain unchanged.
JlO GETTING STARTED
)
)
f )
< )
KMiUlEl DF terminator
No parameters are used; a numeric parameter will
cause error 2 and the instruction will not execute.
A DF command sets the following plotter functions to the conditions
shown in the following table. PI and P2 are not changed.
Default Conditions
F u n c t i o n
Plotting mode
Relative character direction
Line type
Line pattern length
Input window
Relative character size
Symbol mode
Tick length
Standard character set
Alternate character set
Character set selected
Character slant
Mask value
Digitize clear
Scale
Pen velocity
Label terminator
Chord angle*
C o n d i t i o n s
Absolute (PA)
Horizontal (DR1.0)
Solid line
4% of the distance from P I to P2
Mechanical limits of plotter
Width = 0.75% of (P2
X
- Plx)
Height = 1.5% of (P2
y
- Ply)
Off
tp = tn = 0.5% of (P2
X
- Plx) for Y-tick
and 0.5% of (P2
y
- Pl
y
) for X-tick
SetO
SetO
Standard
0 degrees
223,0,0
On
Off
38.1 cm/s (15 in./s)
ETX (ASCII decimal equivalent 3)
Set to 5 degrees for AA, AR, and CI
*Applicable only to Option 001 plotters that have the serial prefix number
2308A or higher.
The Initialize Instruction, IN
The initialize instruction, IN, returns the plotter's
graphics conditions to the initial power-on state by program control.
This instruction has no effect on handshake protocol or the plotter's
state (programmed on or programmed off) in an RS-232-C environment.
The instruction can be used to return the plotter to a known
state at the beginning of a graphics program so unwanted graphics
parameters such as character size, slant, and scaling are not inherited
from another program. PI and P2 are set to power-on positions.
■tWlftyi IN terminator
GETTING STARTED 1-11