HP 7470 schematic

)

)

ffl Getting Started

( |Q HP-IB Interfacing

L33 Establishing Boundaries and Units

) HH RS-232-C/CCITT V.24 Interfacing

^43 Controlling the Pen and Plotting

■II HP-IL Interfacing

J[l Enhancing the Plot

) Qj An HP-IB Overview

•^3 Labeling

J

BO Instruction Syntax

INTERFACING

AND

PROGRAMMING

MANUAL

HP 7470A

Graphics Plotter

RS-232-C/CCITT V.24

..DESIGNED FOB..

'SYSTEMS'

P

Jtl Digitizing

Reference Material

Obtaining Information from the Plotter

^ Putting the Commands to Work

ID

) PART

\ MICROFICHE NO. 07470-90051 LfiM PACKARD PRINTED IN U.S.A.

NO.

07470-90001 WAo% HEWLETT OCTOBER 1984

)

)

)

)
)
)

J

"\

)

)

3

3

1

/

)

tbutiitmt.

)

J

')

)

')

)

•"

')

■)

-s

INTERFACING

AND

HP 7470A

Graphics Plotter

PROGRAMMING

MANUAL

s

^

RS-232-C/CCITT V.24

p

S

NO POSTAGE

NECESSARY

IF MAILED

IN

THE

UNITED STATES

BUSINESS REPLY MAIL

FIRST CLASS PERMIT

NO.

5963 SAN DIEGO. CA

U.S.A.

POSTAGE WILL BE PAID BY ADDRESSEE

HEWLETT

E£l

San Diego Division
Attn: Marketing Communications

16399 West Bernardo Drive

San Diego, CA U.S

PACKARD

A.

92127-9989

©1982,

16399 W. Bernardo Drive. San Diego, CA 921271899

1984, by Hewlett-Packard Company

-rti^sto*

''-Seim— . *- '***!&

&

■.

Sd

,1

»j

i

Vfl

'>*S.

)

Manual Summary

Chapter 1: Getting Started

Contains information concerning manual usage, a description of the
plotter, its interfaces, the HP-GL language, and three instructions.

Chapter 2: Establishing Boundaries and Units

Explains the concept of plotting area, plotter and user units, scaling,
and the instructions used to set and output the scaling points and
window, and to scale the plotting area.

Chapter 3: Controlling the Pen and Plotting

Describes the instructions for pen control and vector plotting.

Chapter 4: Enhancing the Plot

Describes instructions for drawing tick marks and differentiating traces.

Chapter 5: Labeling

Describes the instructions used in labeling to set direction, size, and
slant of characters, as well as instructions for character set and label
terminator selection and for designing your own characters.

Chapter 6: Digitizing

Describes the instructions used to digitize with the plotter and demon­strates how to check for the presence of a digitized point.

Chapter 7: Obtaining Information from the Plotter

Describes the instructions used to obtain information about pen posi­tion, errors, and capabilities of the plotter.

Chapter 8: Putting the Commands to Work

A step-by-step example illustrating the procedures to be followed to
draw labels and plot data using HP-GL instructions.

Chapter 9: HP-IB Interfacing

Summarizes operation of the plotter with the Hewlett-Packard Interface
Bus (HP-IB) and explains the methods for addressing and sending and
receiving data over the interface bus.

Manual Summary (Continued)

Appendix B: Instruction Syntax

Provides a summary of both HP-GL and device control instructions.

Appendix C: Reference Material

Includes a summary of default conditions, error messages, scaling
equations, NOP instructions, ASCII codes, and character sets.

Chapter 10: RS-232-C/CCITT V.24 Interfacing

Describes how to connect the plotter with a terminal and/or computer,
summarizes the methods for establishing a handshake protocol be-

tween the plotter and computer, and explains the device control instruc-

tions that are used to set up and control the handshake protocol.

Chapter 11: HP-IL Interfacing

Describes the Hewlett-Packard Interface Loop (HP-IL) and explains the
methods for sending and receiving data over the interface loop.

Appendix A: An HP-IB Overview

Provides an overview of the Hewlett-Packard Interface Bus (HP-IB).

ii MANUAL SUMMARY

MANUAL SUMMARY iii

)
)
)

)

)

)

)

)

)
)
)

)

3

)
)

mm

)

)
)
)
)

)

)

)

)

)

)
)
)

)

)

Table of Contents

Chapter 1: Getting Started

What You'll Learn in This Chapter

HP-GL Instructions Covered

Terms You Should Understand

How to Use HP 7470 Documentation

For First Encounters with the 7470
For First Encounters with HP-GL
For Experienced HP-GL Programmers

Understanding Manual Conventions and Syntax
A Brief Look at the 7470 Plotter
The 7470 Plotter's Instruction Set
HP-GL Syntax
How to Use the Examples in This Manual 1
The Default Instruction, DF 1
The Initialize Instruction, IN 1
The Input Mask Instruction, IM 1
Looking Ahead 1

Chapter 2: Establishing Boundaries and Units 2-1

What You'll Learn in This Chapter 2-1

HP-GL Instructions Covered 2-1

Terms You Should Understand 2-1
The Plotting Area 2-2
Unit Systems 2-3

The Plotter Unit 2-3

User Units 2-3
Setting the Scaling Points 2-3

Setting PI and P2 Manually 2-4
The Input PI and P2 Instruction, IP 2-4
The Output PI and P2 Instruction, OP 2-5
The Scale Instruction, SC 2-6
The Input Window Instruction, IW 2-9
The Output Window Instruction, OW 2-10
Advanced Programming Tips 2-11

Chapter 3: Controlling the Pen and Plotting 3-1

What You'll Learn in This Chapter 3-1

HP-GL Instructions Covered 3-1

Terms You Should Understand 3-1

; iv TABLE OF CONTENTS

P ::"! Table of Contents (Continued)

Chapter 3: Controlling the Pen and Plotting (Continued)

rrm

fgr 3^

C 3

iR.

^0~ MM Plotting with Variables 3-11

The Pen

The Select Pen Instruction, SP 3-2

The Velocity Select

-™ The Plot Absolute Instruction, PA 3-4
The Plot Relative Instruction, PR 3-8

~~ The Circle Instruction, CI 3-12

am The Arc Absolute Instruction, AA 3-17

Instructions, PU and PD 3-2

Instruction, VS 3-3

5

~U3 The Arc Relative Instruction, AR 3-19

^T 3 Chapter 4: Enhancing the Plot 4-1

" What You'll Learn in This Chapter 4-1
_ n HP-GL Instructions Covered 4-1
!■'

IB The Tick Instructions, XT and YT 4-2

The Tick Length Instruction, TL 4-2
P: 3 The Symbol Mode Instruction, SM 4-4
~ - J The Line Type Instruction, LT 4-6

jm:

:a^ Chapter 5: Labeling 5-1

What You'll Learn in This Chapter 5-1

; "J HP-GL Instructions Covered 5-1

E

:

™ Terms You Should Understand 5-1

Plotter Character Sets 5-2

E; ill The Designate Standard Character Set Instruction, CS 5-3

The Designate Alternate Character Set Instruction, CA 5-4

f *m The Select Standard Set Instruction, SS 5-4
C': ifl The Select Alternate Set Instruction, SA 5-5

i The Define Terminator Instruction, DT 5-6

C i ^3 The Label Instruction, LB 5-7

Labeling with Variables 5-9

,. The Absolute Direction Instruction, DI 5-10

E

1

i3 The Relative Direction Instruction, DR 5-11

Spacing Between Characters 5-12

C; fj The Character Plot Instruction, CP 5-13

' The Absolute Character Size Instruction, SI 5-15

_j^

The Relative Character Size Instruction, SR 5-16

Rll3 The Character Slant Instruction, SL 5-18

x

»fc^

--"3 TABLE OF CONTENTS V

)
)
)

)

)

)

)
)

)

3

)

3

)

)

3
3
3

'iff-iftti!iiTiffiriiiiiii»iiiiiiMiii

3

)

)

)
)
)

3

)

)

)

3

)

)

3

3

m

>

Table of Contents (Continued)

) Chapter 5: Labeling (Continued)

)

) Advanced Programming Tips 5-27

) What You'll Learn in This Chapter 6-1
\ HP-GL Instructions Covered 6-1

) The Digitize Point Instruction, DP 6-2

)

) Digitizing with the 7470 6-4

) Manual Method 6-4

) HP-GL Instructions Covered 7-1

x Terms You Should Understand 7-1

) Notes for an HP-IB User 7-2

) The Output Status Instruction, OS 7-8

\ Summary of Output Response Types 7-9

( )

The User Defined Character Instruction, UC 5-19
Parameter Interaction in Labeling Commands 5-21

Chapter 6: Digitizing 6-1

Terms You Should Understand 6-1

Preparing Your Plotter for Use as a Digitizer 6-2

The Digitize Clear Instruction, DC 6-3
The Output Digitized Point and Pen Status Instruction, OD 6-3

Monitoring the Status Byte 6-5

HP-IB Interrupts and Polling 6-7

Chapter

7:

Obtaining Information From the Plotter 7-1

What You'll Learn in This Chapter 7-1

A Brief Word about Plotter Output 7-2

Notes for an RS-232-C User 7-2
Notes for an HP-IL User 7-2

The Output Actual Position and Pen Status

Instruction, OA 7-3

The Output Commanded Position and Pen Status

Instruction, OC 7-4

The Output Error Instruction, OE 7-5

The Output Factors Instruction, OF 7-6

The Output Identification Instruction, 01 7-7
The Output Options Instruction, 00 7-7

Table of Contents (Continued)

Chapter 8: Putting the Commands to Work 8-1

What You'll Learn in This Chapter 8-1
Problem 8-2
Solution 8-2

Setup and Scaling 8-2
The Axes and Their Labels 8-3
Adding Color and Emphasis 8-5

Plotting Your Data 8-6
Listing 8-9
Advanced Programming Tips 8-10

Filling and Hatching 8-10
Filling a Bar 8-10
Hatching a Bar 8-12
Filling Segments of Pie Charts 8-13

Chapter 9: HP-IB Interfacing 9-1

What You'll Learn in This Chapter 9-1
HP-IB Implementation on the 7470 9-2
Interface Switches and Controls 9-2

Addressing the Plotter 9-2

Bus Commands ■ 9-4

Reaction to Bus Commands DCL, SDC, and IFC 9-4
Serial and Parallel Polling 9-4

Addressing the 7470 as a Talker or Listener 9-6

Computers with No High Level I/O Statements 9-6

Computer with High Level I/O Statements 9-6

Sending and Receiving Data 9-7

Computer-to-Plotter 9-7
Plotter-to-Computer 910

Chapter 10: RS-232-C/CCITT V.24 Interfacing 10-1

What You'll Learn in This Chapter 10-1
Setting Up Your RS-232-C Plotter: a Checklist 10-2
Plotter Environments 10-2

Using a Plotter Directly Connected to a

Computer Mainframe or Personal Computer 10-2

Using a Plotter in an Environment with a Terminal 10-4

Using the Plotter in a Terminal-only Environment 10-9

Connecting the RS-232-C Interface 10-10

VI TABLE OF CONTENTS

J

TABLE OF CONTENTS Vll

)

)

)
)
)
)

3
3

)

3
3

)
)
)

)

3
3

MiiiniUiwWiiiiiiii iiiiniiir'fii -iniraBiTu utiiirwi-Tn--i-nr r r .r-.inrn iMfin.1 - .ir-.ii^.,.■ i«->i ^-n-mi.,.,!,,.

^,

MiM^m^m^MmMmWaKK^^a--^-.

3

3

)

3

)

)

)

3

)
)
)

)
)

)

3

)

ammiMmimmmm

Table of Contents (Continued)

) Chapter 10: RS-232-C/CCITT V.24 Interfacing (Continued)
\ Output Baud Rate 10-12

Stop Bits 10-13

-' Transmission Errors 10-13

) Handshaking 10-14

N

Software Checking

)
)
)

)

)
)

)

3

')

)

)

)

)

)

)
)

)

mm

)

)

)

:>

)

)

)

)

)

)

)
)

)

)

)

HP-IL — Hewlett-Packard Interface Loop — an interface used on some
Hewlett-Packard personal computing products to communicate with
peripheral devices such as the 7470 plotter. The HP-IL interface is
standard on the Option 003 plotter.

)

B

)

How to Use HP 7470 Documentation

) This manual contains interfacing and programming information for

the HP 7470 Plotter and all its interfacing options. The Option 001
plotter is equipped with the RS-232-C/CCITT V.24 Interface. The Option
002 plotter is interfaced through the Hewlett-Packard Interface Bus
(HP-IB) which conforms to ANSI/IEEE 488-1978 specifications. The
Option 003 plotter is equipped with the Hewlett-Packard Interface Loop
for personal computing devices. All interfaces use the Hewlett-Packard
Graphics Language (HP-GL) for control of plotter graphics capabilities.
Unless specifically noted, all information in this manual pertains to all
configurations.

NOTE: All information in this manual for Option 001 plotters applies
equally to RS-232-C and CCITT V.24 interfaces. For purposes of sim­plicity, both are referred to as RS-232-C. ■

Documentation for this plotter is designed to enable you to use the
plotter easily without reading unnecessary manuals. All plotters are
shipped with this manual, an Operator's Manual (Part No. 07470-

90002), an Interconnection Guide (07470-90003), and a Reference Card
(07470-90004). The Operator's Manual contains all information you will
need to operate, but not program, the plotter. The Interconnect Guide
explains how to physically connect your plotter to certain computers or
calculators, and contains instructions for verifying that the connection
has been made. The Reference Card contains a list of the plotter's HP-

GL instructions with their parameters, its device control instructions

for the RS-232-C version, and a list of error numbers and their meanings.

For First Encounters with the 7470

If you have just received your HP 7470, read the Operator's Manual
and the Interconnection Guide before attempting to operate the plotter.
After inspecting your plotter, its power cord, and accessories as
described in the Operator's Manual, refer to the appropriate chapter of
this manual for initial setup and addressing or handshaking protocol
for your configuration. RS-232-C users should read Chapter 10, HP-IB
users should read Chapter 9, and HP-IL users should read Chapter 11.

For First Encounters with HP-GL

If you have never programmed in HP-GL, after reading the interfacing
chapter, read Chapters 1 through 5 in order. These chapters describe
the instructions you will use in almost every application. Running the
examples given with the instructions will help you learn. Next, read

Chapter 8 to see how all the instructions work together in a program.
When you have an application requiring digitizing or plotter output,
read Chapters 6 and 7.

For Experienced HP-GL Programmers

If you are an experienced HP-GL programmer, you may find Appendix
B of this manual or the Reference Card most helpful. Since there are

differences in syntax between this and other plotters, you should read

Chapter 1 of this manual before programming. The 7470 has added

capabilities not found in earlier plotters. Among these are the ability to

plot to non-integer user-unit values, to mirror labels using negative size
and direction parameters, and to output the current window values. To
understand these differences, you need to read the sections on scaling
(SC,

Chapter

and direction in Chapter 5. In the instruction set summary in Appendix

B,

page numbers for the complete description are listed with each

instruction.

2),-

plotting (PA and PR, Chapter 3), and setting label size

Understanding Manual Conventions and Syntax

Before reading any part of this manual, you should understand the
meaning of type styles, symbols, and number representation used in
text. A detailed explanation of syntax symbols is given in the section
entitled HP-GL Syntax in this chapter and Command Syntax for
Device Control Instructions in Chapter 10. The following conventions
also apply. Words typed in small boldface type are either buttons,
switches, or words actually found on the plotter or computer. Headings
in liWHiMJI type are used to help locate specific parts of the writeup of
an instruction. i:i*'ia:M^ type in a smaller size is used to denote a single
ASCII character which should be sent to the plotter. Numbers are
typed using SI (International System of Units) standards; numbers
with more than four digits are placed in groups of three, separated by a

1-2 GETTING STARTED

GETTING STARTED 1-3

)

)

.)

)

)

)
)
)

)
)
)

)

)
)
)

)

)

MMMU

)
)

)
;

)

)
)

)

)

)
)

)

;
)

)

J

tf

)

'

)

V

)

)
)

■■

.)

)

<:

)

;

)

'

)

<■

)

(

)

space instead of commas, counting both to the left and right of the
decimal point (54 321.123 45).

Follow the documentation road map below:

ALL USERS

OPERATOR'S

MANUAL

07470-90002

INTERCONNECTION

GUIDE

07470-90003

RS-232-C USER

INTERFACING AND

PROGRAMMING

MANUAL,

CHAPTER 10

07470-90001

HP-IB,

USERS

HP-IL

^

t

»

—4

►

•

USER OF SOFTWARE

PACKAGE

YOUR

SOFTWARE MANUAL

GRAPHICS ROM USER

GRAPHICS ROM

MANUAL

HP-GL PROGRAMMER

INTERFACING AND

PROGRAMMING

MANUAL

07470-90001

CHAPTERS 1-8, AND

CHAPTER 9, 10, OR 11

A Brief Look at the 7470 Plotter

The HP 7470 Graphics Plotter is a vector plotter which produces high

quality, multicolor graphics plots on two sizes of drawing media:
English ANSI A
programmable pen velocity and a choice of standard fiber tip or trans­parency pens, the 7470 can produce distinctive graphics not only on
standard paper, but also on other media such as transparency film.

The plotter offers both fast plotting speed and high line quality,

achieved using Hewlett-Packard's micro-grip drive technology. This
technology provides low-inertia grit-covered wheels to move the paper
in one axis while the pen moves along the other axis. Plotting occurs
with approximately 2 g acceleration and a maximum velocity of 38.1
cm/s (15 in./s). The result is exceptional line and character quality and
high throughput. The 7470 has addressable resolution of 0.025 mm
(0.001 in.) and repeatability of 0.10 mm (0.004 in.) for any given pen.

The multicolor graphics capability is provided by programmed or front­panel selection of two pens. If additional colors are desired, the pro­gram can be paused to allow manual installation of additional pens.
Seven different dashed-line fonts and symbol mode plotting provide

additional trace identification capabilities.

Character plotting speed of up to six characters per second enables you
to produce fully-lettered graphs quickly. Annotation can be easily done

using any of five character sets, including three European sets. Text
can be written in any direction, with or without character slant, and in
varying sizes.

The 7470 is engineered to be especially useful in the areas of business

graphics, statistics, medicine, numerical control, surveying, and engi­neering design. An optional overhead transparency kit enables you to
produce high quality graphic transparencies from your plotting pro-

grams. For faster comprehension, you can present economic trends,
engineering or scientific data, marketing plans, profit data, or sales
forecasts pictorially. And with a choice of media, you can create paper
hardcopy for an individual's attention or transparencies for group

presentations.

Whether data are tabulated, measured, or computed, depend on the
reliable 7470 to prepare multicolored plots of excellent line quality and

high resolution.

(8V2 X

11 in.) or metric ISO A4 (210 X 297 mm). With

{

)

1-4 GETTING STARTED

MIMH

tJUmitmi/aH

■^^^^—

■J-^**—^-**;*

GETTING STARTED

-^.--

1-5

•,Q...i^^.

■■•

)

)
)

0

)

)

)
)

)
)

)
)
)

)

)

)

)

m*

MMMMH

)

i

)

)

;
)

)

■'

-

)

)

;■ )

' )
\ )

)

)

.

)

)

«*_J

)

The 7470 Plotter's Instruction Set

All three interface configurations for the HP 7470 Plotter use the same
Hewlett-Packard Graphics Language (HP-GL) instruction set, with

i

minor exceptions.* HP-GL consists of two-letter mnemonic instructions
which activate the plotter. A table listing the instructions alphabetically
is located at the end of the next section. Syntax descriptions and
explanations of these instructions are contained in Chapters 1 through

8. Six additional HP-GL instructions cause no operation but are in­cluded for compatibility with other HP plotters. These instructions are
listed in Appendix C.

Fourteen additional instructions, called device control instructions, are
required by the RS-232-C configuration. These instructions are used to
establish plotter output and handshake protocol, and to control condi­tions which are pertinent only to the RS-232-C environment. In an
RS-232-C plotter, all HP-GL instructions enter the plotter's internal
buffer and are executed in a first-in, first-out sequence. Device control
instructions do not enter the buffer, but instead are executed imme­diately upon receipt. Refer to Chapter 10 for the syntax description and
an explanation of the device control instructions.

HP-GL Syntax

An HP-GL instruction is a two-letter mnemonic, which may be upper­or lowercase. A command is defined as an instruction followed by its
parameter field, if any, and a terminator. If parameters follow the
mnemonic, they must be separated from each other by at least one
comma or space, or by a + or — sign which may be preceded by commas
or spaces. Optional commas and/or spaces may be used as separators
before, after, and between the mnemonic and before the terminator. An
instruction is terminated by a semicolon, nonalphabetic and nonnu­meric characters such as # or $, or by the next mnemonic. If you have
an HP-IB or HP-IL plotter, a line feed can also terminate an instruction.
(Note that if you have an RS-232-C plotter, a line feed is not a valid
terminator.) Some instructions will execute immediately after the
mnemonic or last required parameter is received. When this is the case,
the designation for the terminator is shown in parentheses in the
syntax description. The syntax is shown on the next page.

*Option 001 provides 45 instructions; Option 002 provides 42 instructions;

Option 003 provides 41 instructions. Refer to the Plotter Instruction Set table
in this chapter.

INSTRUCTION PARAMETER FIELD

MNEMONIC (AS REQUIRED) (AS REQUIRED)

J-^L I _J

Sep X Sep X Sep Parameter Sep Parameter Sep Terminator

OPTIONAL SEPARATORS ^^ REQUIRED SEPARATOR

(0OR MORE COMMAS

AND/OR SPACES)

NOTE: The syntax implemented on the 7470 is extremely flexible and

differs from that used on other Hewlett-Packard plotters such as the

HP 9872. Therefore, any software written for the 7470 which takes ad-

vantage of its less rigorous syntax will not be able to drive most other

HP plotters. If software is to be used with other HP-GL plotters, the

more rigorous syntax of the HP 9872 plotter should be used.

XX Parameters (.Parameters) Terminator

INSTRUCTION '

OPTIONAL PARAMETERS

The 9872 syntax does not allow separators between the characters of
the mnemonic. One comma must separate parameters. Only; or LF
may be used as the terminator for HP-IB or HP-IL plotters, and only ;
may be used as the terminator for RS-232-C plotters. In addition, pa­rameters requiring integer format may not contain a decimal point or
decimal fraction. ■

Some instructions have optional parameters which, when omitted,
assume a default value. In order to omit a parameter, all subsequent
parameters in the same instruction must be omitted. The only excep­tion is the pen parameters in the HP-GL instruction, UC.

The label instruction, LB, is a special case; it must be terminated with

the label terminator character. This character defaults to the ASCII
end-of-text character, ETX, whose decimal equivalent is 3. The label
terminator may be changed from its default value using the define
terminator instruction, DT.

The parameter fields must be specified in the format defined by the
syntax of each respective HP-GL instruction. The format can be of
three types:

1.

Integer Format — a parameter in integer format between —32 768.0000

and +32 767.9999. Decimal fractions of parameters which must be

integers are truncated. If no sign is specified, the parameter is

assumed to be positive.

FOR RS-232-C PLOTTERS

;OR LF FOR HP-IB OR

HP-IL PLOTTERS

1-6 GETTING STARTED

Mann

«itei

GETTING STARTED 1-7

^^tmm^timtmit^tmimi^iiiitmm

;

)

)

)

)

)

)

)

)

)

)
)
)

)
)

)

)

MlHiiiliHtfiilMiHiialli

MHWiE&i:^

mm

;

)

)

)

)

)
)
)

)

)

;

)

)

J

)

;

)

2.

Decimal Format — a number between -128.0000 and 127.9999 with

)
)
)

:>

)

)

)

)

an optional decimal point and decimal fraction with up to four
significant digits. If no sign is specified, the parameter is assumed to
be positive.

3.

Label Fields — any combination of text, numeric expressions, or

string variables. Refer to The Label Instruction, LB, Chapter 5, for a
complete description.

Some instructions such as PA, PR, PU, and PD may have multiple
parameters. Separators are required between these parameters. These
optional parameters are shown in parentheses in the syntax descriptions.

The syntax shown under the description of each HP-GL instruction
uses the following notations:

AfA/emonic

necessary parameter
( )

C....C

(...)
terminator

(terminator)

The following table shows the 7470's HP-GL instruction set.

Instruction

AA

X,Y, arc angle (, chord angle)

AR

X,Y, arc angle (, chord angle)
n

CA
CI

radius (, chord angle)

CP

spaces, lines

CS

m
DC
DF

For readability, the mnemonic is shown upper­case and separated from the parameters and/or
terminator.

All typeset items are required parameters.
All items in parentheses are optional.
Any number of labeling characters.
Any number of X,Y coordinate pairs.
; or any nonnumeric or nonalphabetic character

such as $ or #, or the next mnemonic. LF is also
valid for HP-IB and HP-IL plotters.

Terminator for an instruction which will execute
after the last necessary parameter is received.

Plotter Instruction Set

Description

Arc absolute*
Arc relative*
Designate alternate set n
Circle*
Character plot
Designate standard set m

Digitize clear

Set default values

Plotter Instruction Set (Continued)

Description

run, rise

DI
DP
DR

run, rise
c

DT
IM

e(,s(,p))
IN
IP

Plx.Ply (, P2x,P2y)

IW

Xio,Yi0,Xhi,Yhi

C....C

LB
LT

t(,l)
OA

Instruction

Absolute direction
Digitize point
Relative direction

Define label terminator
Input e, s, and p masks
Initialize
Input PI and P2
Input window
Label ASCII string
Designate line type and length

Output actual position

and pen status

OC

Output commanded position

and pen status

OD

Output digitized point

and pen status
OE
OF
OI
OO
OP
OS
OW
PA

x,y(,x,y(....))

PD

(x,y(,...))

PR

x,y(,x,y(,...))

PU

(x,y(,...))

SA

SC

Xmin,Xmax,Ymin,Ymax

SI

width, height

SL

tan 0

Output error
Output factors
Output identification
Output options
Output PI and P2
Output status
Output window
Plot absolute
Pen down
Plot relative
Pen up
Select alternate character set
Scale
Absolute character size
Absolute character slant

(from vertical)

SM

c

SP

n

SR

width, height

ss

TL

tp(,tn)

UC

(pen,)x,y,pen(,...)

V

VS

XT
YT

*Available only with Option 001 plotters that have the serial prefix number

2308A or higher.

'*Not available with Option 003.

Symbol mode c

Select pen
Relative character size
Select standard character set

Tick length

User denned character**
Select velocity v
X-axis tick
Y-axis tick

1-8 GETTING STARTED

MMiiiHiiiitaMii

GETTING STARTED 1-9

warn

)

)

)

)
)
)
)
)

)

)
)
)

)

)
)
)

)

)
)
)

)

)

)

)

)

)

;

>

>

)

£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.

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

Function

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*

*Applicable only to Option 001 plotters that have the serial prefix number

2308A or higher.

Absolute (PA)
Horizontal (DR1.0)
Solid line
4%

of the distance from PI to P2
Mechanical limits of plotter
Width = 0.75% of (P2X - Plx)

Height = 1.5% of (P2y - Ply)
Off

tp = tn = 0.5% of (P2X - Plx) for Y-tick

and 0.5% of (P2y - Ply) 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

Conditions

The Initialize Instruction, IN

The Default Instruction, DF

tions to a predefined state.

)

f

<

lUaxl 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

)

)

The default instruction, DF, sets certain plotter func-

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

)

)

)

)
)

)

)

)

)
)

)

)
)
)

)

)
)
)
)

)

)

)

)

)

)

)

;

)

)

)

)
)
)

>. I^HUMi'MIHli'l NO parameters are used; a numeric parameter will K.-—«-3

J cause error 2 and the instruction will not execute. I

) An IN command is the equivalent of switching the plotter off and then

"\ on again (except that conditions set by escape code sequences are not

changed in an RS-232-C environment). The initialize command sets the

) plotter to the same conditions as the default command and sets these

additional conditions.

)

v • The pen is raised. 1ft! ™^3

• The scaling points Pi and P2 are set to the points PI = 250,279 and ^~ "^

) P2 = 10 250,7479.
) • All HP-GL errors are cleared. Bit position 3 of the output status byte ifW' J| j

-v is set to true(l) indicating the plotter has been initialized. (This bit is 1
) cleared by OS.) '

) • The setting of the US/A4 switch (for paper size) is read, thus

\ establishing the limits within which the pen can move (mechanical

hard clip limits).

T

El SJ

The Input Mask Instruction, IM

J HlwHHIillFlltl The input mask instruction, IM, controls the conditions
~N

under which HP-GL error status is reported, the conditions that can

' cause an HP-IB service request message, and the conditions that can

cause a positive response to an HP-IB parallel poll.

UWM With all three interface configurations (HP-IB, HP-IL, and RS- —*

232-C),

this instruction can be used to change the conditions under fT^~^~3

which HP-GL error status is reported. In an HP-IB system only, the

instruction is used to enable the plotter to send a service request «! r-—.

message when specified bits of the status byte are set, and/or enable a i^' J_3

positive response to a parallel poll under the conditions specified.

--" " " " \

"\ BJiJIiftl IM E-mask value (,S-mask value (,P-mask value))

(terminator)
or

IM (terminator)

■9<JI:Ui1llllfl
and P-masks are of no use and are ignored if present. The E-mask is H J , _

used by all three configurations. J5« ^Jj

The E-mask value specified is the sum of any combination.of the bit

values shown in the following table. When an HP-GL error occurs, the
bit in the E-mask corresponding to the error number as shown below is

tested to determine if the error bit (bit 5) of the status byte is to be set

and the front panel

there is no way to ever determine if that error occurred.

In both

the RS-232-C and HP-IL configurations, the S-

ERROR

LED is to be turned on. If a bit is not set,

3

EH3

E-Mask

Bit Value

1
2
4
8

16

32

64

128

The default E-mask value of 223 (128 + 64 + 16 + 8 + 4 + 2 + 1) will
specify that all errors except error 6 will set the error bit in the status
byte and turn on the ERROR LED whenever they occur. Error 6 will not

set the error bit or turn on the ERROR LED if it occurs, since it is not
included in the E-mask value. Errors 4 and 7 never occur so setting the
E-mask to 151 will set the same conditions as the default value 223.

The S-mask value specified is the sum of any of the bit values shown
below. It determines when a service request message will be sent. When

a bit of the status byte changes value, the status byte is ANDed with
the S-mask in a bit-by-bit fashion to determine if bit 6 of the status byte
is to be set and the service request message sent. The status of bit 6
changes as plotter conditions change, and is cleared or set as required.

S-Mask

Bit Value

1
2
4

8
16
32

64

128

For example, an S-mask value of 4 specifies that when a digitized point
is available, setting bit 2, the service request message will be sent.
Setting other bits will not send the service request message.

Bit

0

1
2
3

4
5
6

7

Error

Number

1
2
3
4
5
6

7

8

Status Bit

Number

0

1
2
3
4
5
6

7

Instruction not recognized
Wrong number of parameters
Bad parameter
Not used
Unknown character set
Position overflow
Not used
Vector or PD received with pinch

wheels up

Pen down
PI or P2 changed
Digitized point available
Initialized
Ready for data; pinch wheels down

Error

Not used

Not used

Meaning

Meaning

12 GETTING STARTED

GETTING STARTED 1-13

)

)

)

)
)
)
)

)

)

)
)
)

)

)

)

)

)
)
)

)

)

)

)

)

)

)
)

)
)
)

)

)

)

)

)

The P-mask value specifies which of the status-byte conditions will

)

result in a logical 1 response to a parallel poll over the HP-IB interface.

)
)

)
)

)

)

.)

)

)
)
)

)

P-Mask

Bit Value

1
2
4

8

16

32

For example, a P-mask value of 48 specifies that only bits 4 and 5 (16 +

32) of the status byte can cause the plotter to respond to a parallel poll
with a logical 1 on the appropriate data line.

The plotter, when set to default values or initialized, automatically sets

the E-mask to 223, the S-mask to 0, and the P-mask to 0. An IM
command without parameters or with invalid parameters also sets the
masks to the default values 223,0,0.

Status Bit

Number

0
1
2
3
4
5

Meaning

Pen down
PI or P2 changed
Digitized point available
Initialized
Ready for data; pinch wheels down
Error

J

)

;

)

)
)

)
1-14 GETTING STARTED

)

^

EE3

^3

Looking Ahead

Of course you want to use your plotter to create high quality graphic

plots.

Most plots fall into one of three broad classes: line graphs, bar
graphs, or pie charts. Chapter 8 contains a discussion of a line graph.
Shown below are a bar graph and a pie chart.

Pie charts are an effective way to show parts of a whole entity; the
slices of the pie are the component parts. The pie chart here has some
segments "exploded" for emphasis. To construct a pie chart, the data is
computed as a percentage of the total and each data value is converted
to the appropriate segment of a full 360-degree circle. A simple circle­drawing program is found under the PA instruction in Chapter 3. To
create a pie chart you'll need to draw segments of a circle (arcs) and
connect the endpoints of the arcs to the circle's center with plotted
lines.

There are three types of bar graphs; simple bar graphs, stacked bar

graphs, and clustered bar graphs. The simple bar graph here shows that
sales are increasing. Bar
graphs are essentially a
collection of rectangles;
i.e., four plotted lines.
Each of these rectangles
is filled; refer to the ad­vanced programming tips

at the end of Chapter 8
to learn how to create a
filled or hatched area. A

stacked bar might be used
to show these same sales

data broken down into

sales by region. Portions

of each bar would be

colored or shaded differ-

ently to show the sales in

each region. Another way

of showing sales by region

would be to use a separate

bar for each region and

to "cluster" all the bars

for one year together with

a larger space between
each cluster of
is one cluster for each
year of data.

bars.

There

3000

2500

I

a

2000

■5

1500

|

1000

i

SQQ

0

m.

SMITH UNIVERSITY

STUDENT ENROLLMENT BY COLLEGE

fORKTRT - I!

NET SALES

■

■

ml

JLL

1972

1971

III!

1973

1974 1975 1976 1977

GETTING STARTED 1-15

VETERINARY SCIENCE - 21

LAW - S*

AGRICULTURE - IB

1

M.

■

■

1

■ ■

■ ■

1

1979

1978

Ml

19B0

;

)

,)

)
)

)

^

)

)

)

)

)
)
)

)

)

)

)

)

')

)
)
)

)
)
)

)

>
)

)
)
)

Chapter

Establishing Boundaries

and Units

What You'll Learn in This Chapter

In this chapter you will learn about the plotting area, how to define a
point in this area, and the two kinds of units used to describe the plot­ting area. After reading this chapter, you will be able to decide which
units to use for your data. In addition, you will be able to scale the
plotting area into user units appropriate for your data, and to set or
read the current scaling points. You will be able to restrict plotting to
only a portion of the plotting area, and read the current limits of the

plotting area.

HP-GL Instructions Covered

IP The Input PI and P2 Instruction

OP The Output PI and P2 Instruction

SC The Scale Instruction

IW The Input Window Instruction
OW The Output Window Instruction

Terms You Should Understand

Scaling — dividing the plotting area into units convenient for your ap­plication. Units need not be the same physical size in both axes, nor do
there need to be an equal number of units in the X- and Y-axes.

Scaling Points — the points on the plotting surface moved to when the
front panel buttons
user-unit values specified by the parameters of the scaling instruction
SC.

Window — that part of the plotting area in which plotting of points,
lines,

and labels can occur. At power on, the window is set to the
mechanical limits of the plotter. Nothing can be drawn outside the
current window.

Clipping — restricting plotting to a portion of the plotting area by
establishing a window of a certain size.

P1

and P2 are pressed. These points are assigned the

ESTABLISHING BOUNDARIES AND UNITS 2-1

)

3

:>

)

)

)

.)

)

)
)

>

)

)
)

)
)
)
)

)

)

)

-")

)

)

)

)

)

.)

)

)

J

)

?he Plotting Area

The plotting area is that area of the paper in which the pen can draw.

)

The maximum plotting area for the HP 7470 Plotter is 191 X 272 mm

)

(7.5 X 10.7 in.) when the paper switch is set to A4, and is 191 X 257 mm
(7.5 X 10.2 in.) when the paper switch is set to us. These plotting areas

)

permit plotting on either metric A4 size paper or English
paper and allow for a margin beween the plotting area and the edges of

)

the paper.

)

The plotting area should be thought of as a two-dimensional Cartesian
coordinate system. Remember, in a two-dimensional Cartesian coordi­nate system, a point is defined by its X- and Y-coordinates; for example,
200,300 represents a distinct point where X = 200 and Y =
paper is loaded, the orientation of the X- and Y-axes is established as
shown in the following diagram. When looking at the plotter from the
front, the origin is located near the upper-left corner of the paper. From

now on, we will refer to that corner as lower left, since when a plot is
viewed, the minimum point is generally at the lower-left corner of the
plot.

8'/2-by-l

300.

1-inch

When

Unit Systems

There are two unit systems which can be used to define points in the

plotting area: plotter units and user units. Plotter units are always the
same size. The size of a user unit depends on the parameters of the SC
instruction and the settings of the scaling points, PI and P2.

The Plotter Unit

The plotting area is divided into plotter units; one plotter unit equals

0.025 mm. There are approximately 40 plotter units per millimetre, or
approximately 1000 plotter units per inch. One plotter unit is the

smallest move the plotter can make. When the paper switch is set to A4,
the plotting area contains 10 900 plotter units in X and 7650 plotter

units in Y. When the paper switch is set to us, the plotting area
contains 10 300 plotter units in X and 7650 in Y. While the pen can only
plot in the area mentioned above, parameters of plot commands be­tween —32 768 and 32 767 plotter units are understood by the plotter.
When plotting in plotter units, only integer values are used; parameters
are truncated to integers. Refer to The Plot Absolute Instruction, PA, in
Chapter 3.

- )
< )

, )

' )

1 (DEFAULT)

-,i

.-wmwmmwL>mmi^w,mL

+Y

+X

HARD CLIP

LIMITS

(DEFAULT) P2

Si 3

gkj

At power on, upon front-panel reset, and whenever an IN command is

sent to the plotter, the scaling point PI is set to 250,279 plotter units
and the scaling point P2 is set to 10 250,7479 plotter units. These settings
are independent of the setting of the paper switch.

User Units

The plotting area can also be scaled into user units. This is done with

the scale instruction, SC, which assigns values to the scaling points PI
and P2. A user unit may be almost any size. The parameters of the SC

instruction are truncated to integers between -32 768 and 32 767.

Parameters of plot commands must also be in that range but may be
decimal numbers with fractional parts. Decimal fractions are not trun­cated; as a matter of fact, you can set the scaling points at 0,0 and 1,1
and all your data can be decimal fractions between 0 and 1. You can
also use the plot relative instruction to plot to a point which, in user
units,

is beyond the range ±32 768 as long as its location, expressed as
plotter units, is in range. Refer to the plot instructions PA and PR in
Chapter 3. You will probably use the SC instruction and user units for
most plots.

Setting the Scaling Points

Scaling points PI and P2 can be set programmatically using the input
PI and P2 instruction, IP, as described in a following section. PI and
P2 can be set manually using front panel controls ENTER, PI, and

P2.

of2

ESTABLISHING BOUNDARIES AND UNITS

)

ESTABLISHING BOUNDARIES AND UNITS 2-3

)
;

")

)

)
)

)

)

)

)

)

)

)

)

)
)

)
)
)

)

)

)

)

)

)
)

)