AS 1101.6—1989

Australian Standard

Graphical symbols for generalengineering

Part 6: Process measurementcontrol functions andinstrumentation

This Australian Standard was prepared by Committee ME/72, Technical Drawing. Itwas approved on behalf of the Council of Standards Australia on 20 February 1989 andpublished on 18 August 1989.

The following interests are represented on Committee ME/72:

Association of Computer Aided DesignAssociation of Consulting Engineers, AustraliaAustralian Chamber of CommerceAustralian Gas AssociationBureau of Steel Manufacturers of AustraliaConcrete Institute of AustraliaConfederation of Australian IndustryConstruction and Housing Association, AustraliaCSIRO, Division of Applied PhysicsDepartment of Administrative ServicesDepartment of DefenceDepartment of Property and Services, Vic.Electricity Supply Association of AustraliaInstitute of Draftsmen, AustraliaInstitute of Industrial ArtsInstitution of Engineers, AustraliaInstitution of Production EngineersPublic Works Department, N.S.W.Royal Australian Institute of ArchitectsSociety of Automotive Engineers, AustralasiaTelecom AustraliaUniversity of MelbourneUniversity of New South WalesUniversity of Queensland

Review of Australian Standards. To keep abreast of progress in industry, Australian Standards are subjectto periodic review and are kept up to date by the issue of amendments or new editions as necessary. It isimportant therefore that Standards users ensure that they are in possession of the latest edit ion, and anyamendments thereto.

Full details of all Australian Standards and related publications wil l be found in the Standards AustraliaCatalogue of Publications; this information is supplemented each month by the magazine ‘The AustralianStandard’, which subscribing members receive, and which gives details of new publications, new editionsand amendments, and of withdrawn Standards.

Suggestions for improvements to Australian Standards, addressed to the head off ice of Standards Australia,are welcomed. Noti fication of any inaccuracy or ambiguity found in an Australian Standard should be madewithout delay in order that the matter may be investigated and appropriate action taken.

This Standard was issued in draft form for comment as DR 87178.

AS 1101.6—1989

Australian Standard

Graphical symbols for generalengineering

Part 6: Process measurementcontrol functions andinstrumentation

First published as AS 1101.6—1989.

PUBLISHED BY STANDARDS AUSTRALIA(STANDARDS ASSOCIATION OF AUSTRALIA)1 THE CRESCENT, HOMEBUSH, NSW 2140

ISBN 0 7262 5563 7

AS 1101.6—1989 2

PREFACE

This Standard was prepared by the Standards Australia Committee on TechnicalDrawing to provide a universal means of communication between the various interestsinvolved in the design, manufacture, installation, and operation of measurement andcontrol equipment used in the process industries.

Requirements within the industries vary considerably and, in recognition of this, thisStandard sets out basic requirements for symbols, directed towards the needs of thosewhose prime interest is in basic measurement and control functions.

The Standard is based on ISO 3511/1, Process measurement control functions andinstrumentation Symbolic representation, Part 1: Basic requirements; ISO 3511/2,Process measurement control functions and instrumentation—Symbolic representation,Part 2: Extension of basic requirements ; and ISO 3511/4, Industrial processmeasurement control functions and instrumentation—Symbolic representation, Part 4:Basic symbols for process computer, interface and shared display/control functions.Various changes and additions have been incorporated based on Instrument Society ofAmerica Standards and industry practices in Australia. In particular, the flow symbolsspecified in ISO 3511/1, ISO 3511/2, and ISO 3511/4 were considered too large forgraphical display.

The symbols are not intended to replace graphical symbols for equipment as specifiedin other Australian Standards. This Standard has been developed to stand alone withoutthe need for significant reference to other Standards and, for this reason, duplicatessome symbols already shown in other Standards in the AS 1101 series.

Copyright STANDARDS AUSTRALIA

Users of Standards are reminded that copyright subsists in all Standards Australia publications and software. Except where theCopyright Act allows and except where provided for below no publications or software produced by Standards Australia may bereproduced, stored in a retrieval system in any form or transmitted by any means without prior permission in wri ting fromStandards Australia. Permission may be conditional on an appropriate royalty payment. Requests for permission and information oncommercial software royalties should be directed to the head off ice of Standards Australia.

Standards Australia wil l permit up to 10 percent of the technical content pages of a Standard to be copied for useexclusively in-house by purchasers of the Standard without payment of a royalty or advice to Standards Australia.

Standards Australia wil l also permit the inclusion of its copyright material in computer software programs for no royaltypayment provided such programs are used exclusively in-house by the creators of the programs.

Care should be taken to ensure that material used is from the current edition of the Standard and that it is updated whenever theStandard is amended or revised. The number and date of the Standard should therefore be clearly identif ied.

The use of material in print form or in computer software programs to be used commercially, with or without payment, or incommercial contracts is subject to the payment of a royalty. This policy may be varied by Standards Australia at any time.

3 AS 1101.6—1989

CONTENTS

Page

SECTION 1. SCOPE AND GENERAL

1.1 SCOPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41.2 APPLICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41.3 REFERENCED DOCUMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41.4 DEFINITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41.5 SIZE OF SYMBOLS AND DRAWING PRACTICE . . . . . . . . . . . . . . . . . . . . . . . . 51.6 ORIENTATION OF SYMBOLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

SECTION 2. CODES AND ABBREVIATIONS

2.1 IDENTIFYING CODE FOR INSTRUMENT FUNCTIONS (TAG NUMBER) . . . . . . 62.2 ABBREVIATIONS FOR POWER SUPPLY AND PURGE FLUID SUPPLIES . . . . . 6

SECTION 3. SYMBOLS

TABLE 3.1 TYPES OF LINE AND INSTRUMENT LINE SYMBOLS . . . . . . . . . . . . 8TABLE 3.2 DIRECTION OF FLOW, CROSSINGS AND JUNCTIONS

OF INSTRUMENT SIGNALS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9TABLE 3.3 POINT OF MEASUREMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10TABLE 3.4 INSTRUMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10TABLE 3.5 BASIC SYMBOLS FOR COMPUTER-BASED FUNCTIONS . . . . . . . . 12TABLE 3.6 BASIC SYMBOLS FOR SHARED DISPLAY/CONTROL

FUNCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13TABLE 3.7 INTERLOCKS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14TABLE 3.8 CORRECTING ELEMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14TABLE 3.9 BASIC ACTUATING ELEMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . 15TABLE 3.10 BASIC ACTUATORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16TABLE 3.11 EXAMPLES OF CORRECTING UNITS . . . . . . . . . . . . . . . . . . . . . . . 18TABLE 3.12 FLOW PRIMARY ELEMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20TABLE 3.13 LEVEL INSTRUMENT CONNECTIONS . . . . . . . . . . . . . . . . . . . . . . 23TABLE 3.14 PRESSURE REGULATORS, SELF-ACTUATED . . . . . . . . . . . . . . . . . 25TABLE 3.15 SIGNAL MODIFIERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26TABLE 3.16 BINARY LOGIC, ACTION OF BINARY SIGNALS ON

ANALOG SIGNALS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

SECTION 4. EXAMPLES OF USE

4.1 INDICATING, RECORDING, AND ALARM FUNCTIONS . . . . . . . . . . . . . . . . . 324.2 BLIND TRANSMITTERS (NEITHER INDICATING NOR RECORDING) . . . . . . . 344.3 AUTOMATIC CONTROLLERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 344.4 INTEGRATING INSTRUMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 364.5 MULTIPLE DISPLAY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 364.6 MULTIPOINT INSTRUMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 364.7 MULTIVARIABLE DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 374.8 RATIO CONTROL INSTRUMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 394.9 CASCADE CONTROL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 394.10 MULTIVARIABLE CONTROL SYSTEMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 414.11 PROGRAM CONTROL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 424.12 TIME-CYCLE OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 424.13 HAND OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 424.14 SONIC LEVEL ELEMENT AND TRANSMITTER . . . . . . . . . . . . . . . . . . . . . . . 434.15 ON-OFF VALVE SYMBOLISM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 444.16 COMPLEX INTERLOCKING SYSTEMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 454.17 LOOPS WITH COMMON ITEMS GIVEN A SEPARATE LOOP NUMBER . . . . . 464.18 COMPLEX CONTROL SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 474.19 MULTIPLE INSTRUMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 484.20 SHARED DISPLAY/CONTROL EXAMPLES . . . . . . . . . . . . . . . . . . . . . . . . . . . 504.21 MOTOR CONTROL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

AS 1101.6—1989 4

STANDARDS AUSTRALIA

Australian Standard

Graphical symbols for general engineering

Part 6: Process measurement control functions and instrumentation

SECTION 1. SCOPE AND GENERAL

1.1 SCOPE. This Standard specifies symbols and anidentifying code system for depicting instruments,instrumentation systems, process computers andshared display/control functions in the field ofprocess measurement and control in the processindustries.

1.2 APPLICATION. The symbols given in thisStandard are intended for adoption by draftpersonsand instrument specialists in the preparation andinterpretation of technical drawings and diagrams forthe purpose of conveying technical information.

The symbols are intentionally limited to identificationon process flow diagrams, piping and instrumentdiagrams, etc. and do not provide means ofillustrating specific instruments or parts thereof.

1.3 REFERENCED DOCUMENTS. The followingdocuments are referred to in this Standard:

AS1100 Technical drawing1100.101 Part 101: General principles1100.501 Part 501: Structural engineering drawing

1101 Graphical symbols for general engineering1101.5 Part 5: Piping, ducting and mechanical

services for buildings

1109 Graphical symbols for process flow dia-grams for the food industry

1.4 DEFINITIONS. For the purpose of thisStandard, the definitions below apply.

1.4.1 Actuating element— that part of a correctingunit which adjusts the correcting element in responseto a signal from the controller.

NOTE: Actuating elements are also known as ‘actuators’.

1.4.2 Alarm — a device which is intended to attractattention to a defined abnormal condition by means ofa discrete audible signal or visible signal, but whichdoes not itself institute corrective action.

1.4.3 Configurable —indicates the capability of thesystem to allow the user to select from prepro-grammed functions (modular software units) thosewhich are necessary to accomplish a control strategyor other complex functions, without the use ofcomputer language.

1.4.4 Control panel — a panel mounted in a mainplant or control room receiving information fromseveral plant areas and providing an operatorinterface.

1.4.5 Converter — a transducer which responds to aninstrument signal and changes its form.

1.4.6 Correcting element — that part of a correctingunit which directly adjusts the value of the operatingconditions.

1.4.7 Correcting unit — the unit comprising thoseelements (actuating and correcting) which adjust theoperating conditions in response to a signal from thecontroller.

1.4.8 Distributed control system (DCS) —a systemfor process control purposes which, while beingfunctionally integrated, consists of subsystems whichmay be physically separated and remotely locatedfrom one another. These subsystems are normallyconnected by a communication link (e.g. data bus).

1.4.9 Instrument — a device or combination ofdevices used directly or indirectly to measure,display, or control a variable. This term does notapply to internal components of the instruments,e.g. resistor or receiver bellows.

1.4.10 Locally mounted instrument —an instrumentthat is mounted adjacent to the point of measurement.

1.4.11 Local panel — any panel mounted in the field(either adjacent to or remote from the point ofmeasurement).

1.4.12 Loop — a combination of one or more inter-connected instruments arranged to measure or controla process variable.

1.4.13 Point of measurement — the point in theprocess at which a measurement is or may be made.

1.4.14 Primary element — the element or devicewhich generates conditions in the measured variablethat may be detected by a sensing element.

NOTE: A primary element may also be a sensing element.

1.4.15 Process computer — Programmable devicewhich operates on-line in real time on primarilysensing-element-based process data, to perform userspecifiable supervision or control functions (or both).

1.4.16 Programmable — indicates the capability ofthe system to accept instructions in computerlanguage given by the user for performing controlstrategies or complex functions.

1.4.17 Remote mounted instrument — an instrumentthat is mounted at a distance from the point ofmeasurement, and may be mounted in either a localpanel or control panel.

1.4.18 Sensing element — the element directlyresponsive to the value of the measured variable.

COPYRIGHT

5 AS 1101.6—1989

1 . 4 . 19 S h ar e d d i s p l ay / s h ar e d c o n t r o lsystem — System in which shared functions, such asdisplay, control, and communication of process data,are shared in time, i.e. ‘time-shared’ functions. Thesefunctions are generally accomplished by devicescontaining preprogrammed algorithms which areuser-accessible, configurable, and connectable toperform a given control strategy or function.

1.4.20 Tag number — the unique set of identifyingletters and numbers allocated to each functionalelement of a loop.

1.4.21 Transducer — an element or device whichreceives information in the form of one physicalquantity and converts it to information in the form ofthe same or any other physical quantity.

1.4.22 Transmitter — a transducer which respondsto a process variable by means of a sensing element,and converts it to a standard transmission signalwhich is a function only of the measurement.

1.5 SIZE OF SYMBOLS AND DRAWINGPRACTICE. Precise dimension and properties ofgraphical symbols are difficult to specify. Thesymbols of this Standard have been drawn to a sizeconvenient for publication and comprehension. The

size of symbols used will depend on the size anddetail required in the drawing, but the relativeproportions of the symbols should be maintained.

For instruments, computer-based functions, andshared displays/control functions, one key dimensionshould be used to form the symbol, i.e. the samedimension for the diameter, side, diagonal, or acrossthe flats for the circle, square, diamond, or hexagon.The key dimension is chosen to provide adequatespace for the function identifying letters and loopnumber to be located within the symbol.

Where it is desirable or necessary to vary the propor-tions or relative size to give a symbol prominence orfor space limitations or other appropriate reason, thedegree of variation shall be such that the symbolremains unique and readily recognizable.

Where it is the intention to reduce the size of thedrawing on reproduction, the symbols includingletters etc. shall be enlarged proportionally.

Drawing practices used for linework and letteringshall comply with AS 1100.101.

1.6 ORIENTATION OF SYMBOLS. Unless other-wise specified, the orientation of a symbol may bedifferent from that given in Section 3 withoutchanging the meaning.

COPYRIGHT

AS 1101.6—1989 6

SECTION 2. CODES ANDABBREVIATIONS

2.1 IDENTIFYING CODE FOR INSTRUMENT FUNCTIONS (TAG NUMBER).

2.1.1 Tag number. The identification of an instrument shall be defined by a letterand loop number code contained within the instrument function symbol. This codeshall be constructed on the following basis (see Table 2.1):

(a) The first letter shall denote the measured or initiating variable, and shall be inaccordance with Column 2 of Table 2.1, but should be modified, if necessary, bythe addition of a letter in accordance with Column 3 therein.

(b) Succeeding letters shall be in accordance with Column 4 of Table 2.1.

(c) Where there are two or more succeeding letters, they shall be placed one after theother, in sequence I R C T Q S Z A. The letter I may be omitted for aself-indicating recorder.

(d) The allocated loop number should be unique and common to other instruments orinstrument devices of the loop.

(e) A suffix may be added to identify replicated devices in the loop.

(f) A prefix may be added to identify plant areas.

2.1.2 Qualifying letters. Where it is required to denote HIGH or LOW, thequalifying letters H or L may be used in association with the symbol. Other letters maybe used, e.g. for middle.

2.1.3 Position of qualifying letters. Qualifying letters, where used, may be placedinside the symbol, or outside the symbol and adjacent to it.

2.1.4 Position of function-identifying letters. Function-identifying letters shall beplaced inside the symbol and, for panel-located equipment, above the horizontal line.

2.1.5 Position of loop number. If required, the loop number shall be shown insidethe symbol.

The number shall be below the identifying letters and, for panel-located equipment,below the horizontal line.

2.2 ABBREVIATIONS FOR POWER SUPPLY AND PURGE FLUIDSUPPLIES. The following abbreviations are suggested to denote the types of powersupply:

AS Air supplyES Electric supplyGS Gas supplyHS Hydraulic supplyNS Nitrogen supplySS Steam supplyWS Water supply

These designations may also be applied for purge fluid supplies.

The power supply level may be added to the instrument supply line, e.g. ‘AS 100’means a l00-kilopascal air supply; ‘ES 24DC’ means a 24-volt direct current supply.

COPYRIGHT

7 AS 1101.6—1989

TABLE 2.1

LETTER CODE FOR IDENTIFICATION OF INSTRUMENT FUNCTION

1 2 3 4

Letter First letter* (measured orinit iating variable) Modifier* Succeeding letter*

(display or output function)

A Analysis† — Alarm

B Burner, flame — State or status display

C — — Control

D Density Difference —

E All electrical variables† — Sensing element‡

F Flowrate Ratio —

G Gauging position orlength

— Glass

H Hand (manuallyinit iated) operated

— High (alarm)

I — — Indicating

J — Scan —

K Time or time program — Barr ier

L Level — Low (alarm)

M Moisture or humidity — User’s choice§

N User’s choice§ — User’s choice§

O User’s choice§ User’s choice§ —

P Pressure or vacuum — Test point connection

Q — Integrate or totalize Intergrating or summating

R Radiation — Recording

S Speed or frequency — Switching

T Temperature — Transmit ting

U Mult ivariable — Mult ifunction unit

V Vibration — Valve, damper, louvre, actuatingelement, unspecified correcting unit

W Weight or force — Wells

X Unclassified variables,e.g. T.V. camera§

— Cathode ray tube, etc

Y User’s choice§ — Computing relay, relay

Z — — Emergency or safety acting

* Upper case letters should be used throughout, but, for modif iers alone, lower case letters may be used ifthis facil itates understanding.

† A note shall be added outside the circle to specify the property measured.‡ Including any integral protection of the sensitive port ion, e.g. a diaphragm and capil lary system in a

sealed system or mechanical protection of the sensing element.§ Where a user has a requirement for measured or init iating variables to which letters have not been

allocated and are required for repetit ive use on a part icular contract, the letters allocated to ‘User’ s choice’may be used provided that they are identif ied or defined for a part icular measured or init iating variableand reserved for that variable. Where a user has a requirement for a measured or initiating variable thatmay be used either once or to a limited extent, the letter X may be used provided that it is suitablyidenti fied or defined.The letter U may be used instead of a series of fi rst letters where a multiplicity of inputs representingdissimilar variables feed into a single unit .

COPYRIGHT

AS 1101.6—1989 8

SECTION 3. SYMBOLS

TABLE 3.1

TYPES OF LINE AND INSTRUMENT LINE SYMBOLS

* Does not conform to ISO.† A typical distance between quali fiers is 25 mm.

COPYRIGHT

9 AS 1101.6—1989

Examples of application:

NOTE: Instrument symbols are drawn in a thin line.

TABLE 3.2

DIRECTION OF FLOW, CROSSINGS, AND JUNCTIONS OFINSTRUMENT SIGNALS

COPYRIGHT

AS 1101.6—1989 10

TABLE 3.3

POINT OF MEASUREMENT

* Does not conform to ISO

TABLE 3.4

INSTRUMENTS

* Does not conform to ISO.

COPYRIGHT

11 AS 1101.6—1989

Application:

(a) The diameter of the circle should be approximately 10 mm. (See also Clause 1.5.)

(b) The circle is the basic symbol, but ellipses or elongated circles are acceptable toaccommodate alphanumeric identifications specific to an industry, e.g.

(c) The basic symbol may be extended for use as status indication by adding fourperipheral lines thus —

(d) The letter code specified in Table 2.1 shall be used to designate the instrumentfunction, e.g. for a pressure indicator:

(e) The particular panel may be identified alongside the symbol by an alphanumericidentifier or a note located at the lower right sector, e.g.:

(f) Where two or more instrument circles touch, the functions indicated by the lettersin the circles are all incorporated in one enclosure, e.g.

(g) The horizontal lines may be located at any height in the circle.

COPYRIGHT

AS 1101.6—1989 12

TABLE 3.5

BASIC SYMBOLS FOR COMPUTER-BASED FUNCTIONSNOTE: It is permissible to use the basic symbol for computer-based functions throughout for anysoftware-based digital system. This is not intended to preclude the use of the basic symbol for shareddisplay/control functions (see Table 3.6) if the user considers this to be appropriate.

NOTE: Horizontal lines may be dashed to show inaccessible to operator function.

Application:

(a) The width of the hexagon should be approximately 10 mm between two parallelsides.

(b) The hexagon is the basic symbol, but elongated hexagons are acceptable toaccommodate alphanumeric identifications specific to an industry, e.g.

(c) The basic symbol is usually applied in conjunction with other basic symbolsshowing measured process variables or actuated correcting unit. Symbols whichtouch each other imply communication between functions.

(d) For simplification of diagrams, the basic symbol alone may be used.

(e) The letter code specified in Table 2.1 shall be used to denote and identify theprocess computer functions, e.g.

Temperature signal to computer with temperaturerecording and high alarm by computer normallyaccessible to operator at a central panel.

COPYRIGHT

13 AS 1101.6—1989

TABLE 3.6

BASIC SYMBOLS FOR SHARED DISPLAY/CONTROL FUNCTIONS

NOTE: Horizontal lines may be dashed to show ‘inaccessible to operator function’.

Application:

(a) The width of the square and diameter of the circle should be approximately10 mm.

(b) The symbol is not rotatable.

(c) The square with circle is the basic symbol, but an elongation of the symbol isacceptable to accommodate identification.

(d) The letter code specified in Table 2.1 shall be used to denote and identify theshared display/control functions, e.g.

(e) The basic symbol is usually applied in conjunction with other basic symbolsshowing measured process variables or actuated correcting unit. Symbols whichtouch each other imply communication between functions.

COPYRIGHT

AS 1101.6—1989 14

(f) For simplification of diagrams, the basic symbol alone may be used.

TABLE 3.7INTERLOCKS

* Does not conform to ISO.

Application:

The size of the diamond should be approximately 10 mm across the diagonals.

TABLE 3.8CORRECTING ELEMENTS

NOTE: For correcting elements other than those shown in this Table, established symbols (e.g. inAS 1101.5 and AS 1109) may be used.

* Does not conform to ISO.† This symbol is simplif ied and preferred for use in piping and instrumentation diagrams (P & ID). Symbols

for multiport valves are also shown in AS 1109.

COPYRIGHT

15 AS 1101.6—1989

Application:

Valves with three or more ports shall always be drawn showing the throughconnections in the de-energized position, e.g.

TABLE 3.9

BASIC ACTUATING ELEMENTSNOTE: Specific types of valve actuators are shown in Table 3.11

* Does not conform to ISO.

Application:

The connection of actuating element symbol to the correcting element symbol is madeby a thin line.

COPYRIGHT

AS 1101.6—1989 16

TABLE 3.10

BASIC ACTUATORSNOTE: The symbols shown in this Table shall be used where it is desired to show part icular types ofactuators.

* Does not conform to ISO.

COPYRIGHT

17 AS 1101.6—1989

TABLE 3.10 (Cont .)

NOTE: Preferred size relationship of piston and solenoid actuator is 1:2.* Does not conform to ISO

COPYRIGHT

AS 1101.6—1989 18

TABLE 3.11

EXAMPLES OF CORRECTING UNITSNOTE: Response of the actuator to failure of the actuating energy may be indicated as shown in this

Table for the particular example of a control valve. Valves with three or more ports shallalways be drawn showing the through connections in the de-energized posit ion (see alsoTable 3.8).

COPYRIGHT

19 AS 1101.6—1989

TABLE 3.11 (Cont .)

COPYRIGHT

AS 1101.6—1989 20

TABLE 3.12

FLOW PRIMARY ELEMENTS

* Does not conform to ISO.

COPYRIGHT

21 AS 1101.6—1989

TABLE 3.12 (Cont .)

* Does not conform to ISO.

COPYRIGHT

AS 1101.6—1989 22

TABLE 3.12 (Cont .)

* Does not conform to ISO

COPYRIGHT

23 AS 1101.6—1989

TABLE 3.13

LEVEL INSTRUMENT CONNECTIONSNOTE: The word ‘vessel’ is for descriptive purposes only and does not form part of the symbols.

COPYRIGHT

AS 1101.6—1989 24

TABLE 3.13 (Cont .)

* Does not conform to ISO.

COPYRIGHT

25 AS 1101.6—1989

TABLE 3.14

PRESSURE REGULATORS, SELF-ACTUATED

* Does not conform to ISO.

COPYRIGHT

AS 1101.6—1989 26

TABLE 3.15SIGNAL MODIFIERS

NOTES:1. The signal identi fiers (a, b, etc) are for descriptive purposes only and do not form part of the

symbol.2. The lines are drawn as electr ic signals, but can also be pneumatic signals.3. The mathematical relationship may be provided at input or output where required. This is of

part icular importance in Items 3.15.02, 3.15.04, 3.15.07, 3.15.08, 3.15.14, 3.15.15, and 3.15.16.4. The circles shown below may be replaced by the basic symbol for computer-based or shared

display/control functions where applicable (see Tables 3.5 and 3.6).

COPYRIGHT

27 AS 1101.6—1989

TABLE 3.15 (Cont .)

COPYRIGHT

AS 1101.6—1989 28

TABLE 3.15 (Cont .)

Application:The letter code specified in Table 2.1 shall be used to designate the signal modifiers,e.g.

COPYRIGHT

29 AS 1101.6—1989

TABLE 3.15 (Cont .)

Application (cont.):

COPYRIGHT

AS 1101.6—1989 30

TABLE 3.16

BINARY LOGIC, ACTION OF BINARY SIGNALS ON ANALOG SIGNALS

The basic elements are ‘and’, ‘or’, ‘not’, and ‘time lag’ and these shall have circularsymbols.

Where an analog signal is influenced by a binary signal, the result may be that theanalog signal —

(a) retains the last value; or(b) assumes a predetermined value.

This may occur both in the l-state and in the 0-state of the binary signal.NOTES:1. The signal identif iers (a, z, etc) are for descriptive purposes only and do not form part of the symbol.

B represents a binary signal, a and b are analog signals.2. The lines are drawn as electr ic signals, but can also be pneumatic signals.

COPYRIGHT

31 AS 1101.6—1989

TABLE 3.16 (Cont .)

COPYRIGHT

AS 1101.6—1989 32

SECTION 4. EXAMPLES OF USE

4.1 INDICATING, RECORDING, AND ALARM FUNCTIONS.

4.1.1 Flowrate indicator, locally mounted.

4.1.2 Flowrate recorder, locally mounted.

4.1.3 Conductivity recorder, panel-mounted.

4.1.4 Pressure differential recorder, locally mounted.

4.1.5 High pressure alarm, locally mounted.

(Preferred) (Acceptable alternative)

4.1.6 Low pressure alarm, locally mounted.

(Preferred) (Acceptable alternative)

COPYRIGHT

33 AS 1101.6—1989

4.1.7 Level indicator, locally mounted.NOTE: The symbol illustrates that the level in the part icular vessel is indicated. No inference is to bedrawn as to the nature or position of any physical connections to the vessel.

4.1.8 Level indicator, locally mounted, point of measurement inside vessel.

4.1.9 Local low pressure alarm with simultaneous emergency action of correctingunit.

4.1.10 Pressure signal to computer.

4.1.11 Temperature signal to computer. Temperature signal to computer (inputnumber 211) with temperature recording and high alarm by computer normallyaccessible to the operator.

COPYRIGHT

AS 1101.6—1989 34

4.1.12 Flow recording and control by computer.

4.1.13 Control valve. Control valve actuated and position display (open-shut) oncomputer.

4.2 BLIND TRANSMITTERS (NEITHER INDICATING NOR RECORDING).

The symbol for a blind transmitter should be used only where there would otherwisebe ambiguity concerning the nature of the property transmitted (see also examples inClause 4.7).

4.3 AUTOMATIC CONTROLLERS.

4.3.1 Flowrate recording controller. Flowrate recording controller adjusting adiaphragm and spring-operated valve, instrument panel-mounted, valve fails closed.

COPYRIGHT

35 AS 1101.6—1989

4.3.2 Flow recording and indication in control room. Flow indicator in controlroom with retransmission to computer for recording and control.

4.3.3 Pressure recording. Pressure recording and control by computer with ‘back-up’by discrete instruments. When the computer is not controlling communication, the‘back-up’ instrument assumes control.

4.3.4 Flow recording with access in local and indication in central controlroom. Flow recording and control by computer, operator access in local control room,flow indication in central control room.

COPYRIGHT

AS 1101.6—1989 36

4.4 INTEGRATING INSTRUMENTS. Indication and control of quantity transfer,e.g. a positive displacement flowmeter with shut-off device. This does not control therate. Valve fails closed.

Record and control of flowrate using an orifice plate as primary element withsummation of volume.

4.5 MULTIPLE DISPLAY. Where it is necessary to show that a measured value isto be displayed in more than one place, the instrument symbol at the point ofmeasurement may be supplemented by further appropriate symbols, these beingconnected as detailed in Table 3.1.

In the more general case where it is important to show multiple measurement andcontrol functions explicitly, these may be represented by individual instrument andcorrecting unit symbols with appropriate connections by thin lines. Examples of thisprocedure appear in Clauses 4.7, 4.8, 4.9, and 4.10.

4.6 MULTIPOINT INSTRUMENTS. Where a multipoint instrument is to measurethe same physical property at a number of points, the appropriate instrument symbolshall be shown at each point of measurement.

NOTE: A numbering system is necessary to relate each point of measurement to the part icular mult ipointinstrument. The system shown in the following example should not be regarded as internationallyrecommended, but has been included to indicate one possible method of numbering.

COPYRIGHT

37 AS 1101.6—1989

4.7 MULTIVARIABLE DATA.

4.7.1 General. Where a single instrument, e.g. a 3-pen recorder or a data logger, isto measure a number of different physical properties, it may be included in the diagramin either of two ways.

For a simple system, the symbol may be connected to all individual instrument ormeasurement symbols.

In a more complicated installation or one which does not lend itself to such a layout,the symbol for the multivariable data receiving device may be repeated at eachassociated instrument symbol. With this type of presentation, explanatory notes, whichmay or may not be on the flow sheet, are essential, e.g. PRC in the following diagramdenotes an instrument which does not have a transmitting function:

COPYRIGHT

AS 1101.6—1989 38

4.7.2 Automatic scanning. Where the data logger has automatic scanning facilities,this may be shown as follows (two examples):

COPYRIGHT

39 AS 1101.6—1989

4.8 RATIO CONTROL INSTRUMENTS. A controller holding a constant ratiobetween two flowrates both recorded. The ratio is remotely manually pneumaticallyset. Orifice plate primary elements and pneumatic transmitters are used. The valve isdiaphragm and spring-operated.

4.9 CASCADE CONTROL.

4.9.1 Temperature cascade control of flow. Where one controller provides thecommand signal to one or more other controllers.

COPYRIGHT

AS 1101.6—1989 40

4.9.2 Cascade control and indication of temperature. Cascade control andindication and recording of temperature by computer with ‘back-up’ control andindication with common process connections.

NOTE: It is implied that there is a connection between the ‘back-up’ instruments so that, when thecomputer is not controll ing, the output of TIC 260 sets the set point of TIC 261 whose output drives thecontrol valve.

4.9.3 Indication and cascade control of flow level. Indication and cascade controlof level to flow by computer, with connected ‘back-up’ control and indication. Whenthe computer is not controlling, the ‘back-up’ controllers assume control in a mannersimilar to the examples in Clauses 4.3.3 and 4.9.2.

COPYRIGHT

41 AS 1101.6—1989

4.10 MULTIVARIABLE CONTROL SYSTEMS. Where a combining devicesymbolized, for example, by UC, UIC, URC, receives signals from two or moreinstruments and selects from these or combines them to operate one or more correctingunits, the assembly of the symbols may be arranged in either of two ways.

NOTE: In complex systems, explanatory notes on the flow sheet are usually necessary.

For a simple installation, the combining device symbol may be connected to otherinstrument symbols.

In a more complicated installation or one which does not lend itself to such a layout,the symbol for the combining controller may be repeated at each instrument andcorrecting unit symbol. With this type of presentation, explanatory notes, which mayor may not be on the flow sheet, are essential.

COPYRIGHT

AS 1101.6—1989 42

4.11 PROGRAM CONTROL. For example, flowrate recorder-controller whose setvalue is automatically adjusted to a predetermined program in time.

4.12 TIME-CYCLE OPERATION. For example, three valves automatically actuatedaccording to a predetermined program in time, two valves being actuatedsimultaneously.

4.13 HAND OPERATION.

4.13.1 Remote adjustment of the set value of a controller.

4.13.2 Local (indirect) adjustment of a correcting unit.

COPYRIGHT

43 AS 1101.6—1989

4.13.3 Automatic actuating element with integral manual actuating element.

4.14 SONIC LEVEL ELEMENT AND TRANSMITTER.

COPYRIGHT

AS 1101.6—1989 44

4.15 ON-OFF VALVE SYMBOLISM.

Example 1.

In the de-energized condition, the solenoid valve vents the piston actuator toatmosphere.

NOTE: The use of continuation boxes as shown is an example of interfacing drawings. In this example,the drawing is continued on zone number A4, drawing number 001-100.

Example 2.

Use of words to clarify function intent.

COPYRIGHT

45 AS 1101.6—1989

4.16 COMPLEX INTERLOCKING SYSTEMS.

COPYRIGHT

AS 1101.6—1989 46

4.17 LOOPS WITH COMMON ITEMS GIVEN A SEPARATE LOOP NUMBER.

COPYRIGHT

47 AS 1101.6—1989

4.18 COMPLEX CONTROL SYSTEM. A complex control system using selectionof pressure or level as the mode of control, controlling phased control valves withinterlocking for and testing of shutdown systems.

NOTE: For details on continuation boxes, refer to Note to Clause 4.15.

COPYRIGHT

AS 1101.6—1989 48

4.19 MULTIPLE INSTRUMENTS.

4.19.1 Multiple dual connection level instruments.

4.19.2 Displacer type level transmitter with an integral controller.

4.19.3 Overlapping level instruments for long range or multiphase application.

4.19.4 Flow instruments operating from the same primary element but havingseparate connection.

COPYRIGHT

49 AS 1101.6—1989

4.19.5 Differential type flow instruments operating from the same primaryelement and the same connections.

4.19.6 Flow, pressure, and temperature instruments in the same enclosure.

4.19.7 Flow and pressure instruments in separate enclosures operating from thesame connections.

4.19.8 Separate pressure instruments operating from a single connection.

COPYRIGHT

AS 1101.6—1989 50

4.20 SHARED DISPLAY/CONTROL EXAMPLES.

4.20.1 Flow recording on shared display.

4.20.2 Shared pressure control. Shared control and recording of pressure, e.g. bydistributed control system (DCS) with pressure recording by a discrete instrument incontrol room.

COPYRIGHT

51 AS 1101.6—1989

4.20.3 Cascade control.

Instrumentation and functions:

LIC-106 DCS control (master, soft wired to slave)

LSL-107 Discrete low-level alarm switch giving alarm not duplicated in DCS

LSLL-107 Discrete low-level alarm switch giving alarm (not duplicated in DCS) andtripping FV-101

FRC-101 DCS recording control (slave of LIC-106)

TAH-llO Hard-wired high temperature alarm with its own annunciator andduplicated in DCS

HS-103 Hard-wired local manual reset

COPYRIGHT

AS 1101.6—1989 52

4.21 MOTOR CONTROL. Pump driven by a variable speed motor shown.

COPYRIGHT