Standardization in Industrial Control Programming

PLCopen for efficiency in automation

IEC 61131.3 the Industrial Programming Standard

Information at www.PLCopen.org

PLCopen - IEC 61131 - 3

Overview

“There are three classes of people: those who see.

Those who see when they are shown.

Those who do not see.

”

Leonardo da Vinci ( Italian draftsman, Painter , Sculptor , Architect and Engineer whose genius epitomized the Renaissance humanist ideal. 1452 1519 )

"Any sufficiently advanced technology is indistinguishable from magic.“

Arthur Charles Clarke

March 31 st and April 1 st , 2009

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Mile High Industrial and Automation Conference




The goal of this presentation is to provide the attendees with information and a review of the IEC 61131-3 control system automation software standard which is an open (nonpropriety) based standard applicable to the implementation of a PLC Open system including the application of Field Bus technology. The attendees will gain knowledge involving the

IEC 61131-3 software standard utilizing RTU/PLC/DCS.

IEC = International Electro-technical Commission

A World organization that prepares and publishes international standards for all electrical and electronic related technologies

Founded in 1906 * Over 50 participating countries * Different levels of membership


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What is the IEC 61131 standard ?

IEC 61131 is an international standard for programmable controllers consisting of 5 parts:

 Part 1: General information

 Part 2: Equipment characteristics

 Part 3: Programming languages

 Part 4: User guidelines

 Part 5: Communication


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IEC 61131 and PLC Open – Mission

PLC Open is a vendor and product independent world-wide organization that brings greater value to users of

Industrial Control Systems through the pursuit of the IEC 61131-3 software development standard


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Goals of IEC 61131.3 and PLC Open

 PLC Open Certification and compliance testing

 Definition of several levels of IEC 61131-3 compliance

(Base Level, Portability Level, Full compliance Level)

 Establish strict test procedures

 Establish certification tests at independent test institutes

 Ultimate Goal: Portability of PLC programs

Program once run on any hardware platform not hardware specific or dependent


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Table of contents

 Advantages of IEC61131-3 for programmers

 History and international standards 1970 to 1995

 7 parts of the IEC 61131 standard

 IEC 61131-3 software models

 the 5 languages of the IEC 61131-3

 FBs (Function blocks) and POUs (Programmable Organizational Units)

 IEC data types, standard functions and standard function blocks

 PLCopen certification


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Table of contents - continued

 PLCopen compliance levels

 PLCopen training logo

 PLCopen address

"Concern for man himself and his fate must always form the chief interest of all technical endeavors, concern for the great unsolved problems of the organization of labor and the distribution of goods--in order that the creations of our mind shall be a blessing and not a curse to mankind.

Never forget this in the midst of your diagrams and equations ." Albert Einstein


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Advantages of IEC 61131-3

 International accepted standard

• Step by step all suppliers will support it

• Uniform structures, languages, and the way of handling

 It saves you time

• Unique software model and data/ type concept

• You only have to learn it once for different controller types

• Reduced misunderstandings and errors

• Standard functions and function blocks

• Reusability of tested software

March 31 st and April 1 st , 2009 Mile High Industrial and Automation Conference

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Advantages of IEC 61131-3

 Supports safety and quality programming

• Easy and comfortable structuring

• Data typing prohibits programming errors

 Provides the best language for each problem

• Consistent specifications of 5 languages

• Two textual and two graphical languages

• One structuring language, providing an overview

• Availability of high level language

• Possibility to mix different languages


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International Language Standardization

NEMA Programmable Controllers Committee formed (USA)

GRAFCET (France)

DIN 40719, Function Charts (Germany)

NEMA ICS-3-304, Programmable Controllers (USA)

IEC SC65A/WG6 formed

DIN 19 239, Programmable Controller (Germany )

IEC 65A(Sec)38, Programmable Controllers

MIL-STD-1815 Ada (USA)

IEC SC65A(Sec)49, PC Languages

IEC SC65A(Sec)67

IEC 848, Function Charts

IEC 64A(Sec)90

IEC 1131-3

Type 3 report recommendation

70 77 78 79 80 81 82 83 84 85

Source: Dr. J. Christensen


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86 87 88 89 90 91 92 93 94 95

IEC 61131-3 name change

96





The 7 Parts of The IEC 61131 Standard

 Part 1

 Part 2

 Part 3

 Part 4

 Part 5

 Part 7

 Part 8

General overview, definitions IS

Hardware IS

Programming Languages

User Guidelines

Communication

IS

IS

IS

Fuzzy Logic

Technical Report

IS

IS = International Standard


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IEC 61131 - Part 1 - General Overview

 Definitions and glossary of terms used in the standard

 List of related / referenced IEC standards

 Principal functional characteristics of programmable controller systems

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IEC 61131 - Part 2 - Hardware

 Electrical, mechanical and functional requirements for

Programmable Controllers and associated peripherals

 Service, storage and transportation conditions

 Information to be supplied by manufacturer

 Test methods and procedures for verification of compliance of programmable controllers and associated peripherals


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IEC 61131 - Part 3 - Programming

Languages

 Software-, communication- and programming-model

 Definition of five interlinked programming languages

 Syntax and semantics of two textual and two graphical languages: Instruction List (IL), Structured Text (ST), Ladder

Diagram (LD) and Function Block Diagram (FBD)

 Sequential Function Chart (SFC) for program structuring


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IEC 61131 - Part 4 User Guidelines

Assists the user in:

 Utilizing the other parts of the programmable controller standard

 Specifying the requirements for applications

 Selecting and implementing systems

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IEC 61131 - Part 5 Communication

 Based on MMS (Manufacturing Message Specifications)

(still in progress)

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IEC 61131 - Part 7 Fuzzy Logic

 Provides the definition of fuzzy control sets

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IEC 61131 - Part 8 Technical Report

 Provides guidelines for the application and implementation of programming languages for programmable controller

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IEC 61131-3 Software Model

Configuration A

Resource L Resource L

Task1 Task2 Task3 Task4

Program P1 Program P2

FB1 FB2

Program P3

FB3 FB4

Program P4 global and direct addressed variables access paths

Task association

Access path association





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OB1

Other

OBs


FC

FB

FC

FB

FB

FC

OB - Organization Block

FC - Function

FB - Function Block

Memory





Definition of Software Model Terms

 Configuration

A language element corresponding to a programmable controller system

 Resource

A language element corresponding to a signal processing function and its humanmachine interface and sensor actuator functions, like a CPU in your system

 Task

An execution control element providing for periodic or triggered execution of a group of associated program organization units

 Program

Highest level program organization unit, several in - and outputs possible, can call

FBs and Functions

 FB

Program organization unit Function Block, several in - and outputs possible, can call other FBs and Functions


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IEC 61131-3: The Common Elements

• Character set

• Data types

• Variables

(English.........)

(BOOL, WORD, INTEGER.................)

(VAR, VAR_input, VAR_output..........)

• POUs,

Program Organisation Units (Function, Function Block...)

• SFC Elements

(Steps, Transitions.................................)

• Configuration elements:

(Tasks)

•

Basis for software re-use


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7

10

11

12

8

9

13

14

16

17

18

19

20

No. Keyword Data Type Bits

4

5

6

1

2

3

BOOL

SINT

INT

DINT

LINT

USINT

Boolean

Short integer

Integer

Double integer

Long integer

Unsigned short integer

16

32

1

8

64

8

15

UINT

UDINT

ULINT

REAL

LREAL

TIME

DATE

TIME_OF_DAY or TOD

DATE_AND_TIME or DT

STRING

BYTE

WORD

DWORD

LWORD

Unsigned integer

Unsigned double integer

Unsigned long integer

Real numbers

Long reals

Duration

Date (only)

Time of day (only)

Date and time of day

Character string

Bit string of length 8





16

32

64

32

64

8

16

32

64





Directly represented variables – Hardware Addressable Inputs and Outputs

The identifier of a directly represented variable always begins with "%" character.

Below are the naming conventions of a directly represented variable for a channel of a single board. "s" is the slot number of the board. "c" is the number of the channel.

%IXs.c

free channel of a Boolean input

%IDs.c

free channel of an integer input

%ISs.c

free channel of a message input

%QXs.c

free channel of a Boolean output

%QDs.c

free channel of an integer output

%QSs.c

free channel of a message output

Below are the naming conventions of a directly represented variable for a channel of a complex equipment.

"s" is the slot number of the equipment. "b" is the index of the single board within the complex equipment.

"c" is the number of the channel.

%IXs.b.c

free channel of a Boolean input

%IDs.b.c

free channel of an integer input

%ISs.b.c

free channel of a message input

%QXs.b.c free channel of a Boolean output

%QDs.b.c free channel of an integer output

%QSs.b.c free channel of a message output

Below are examples:

%QX1.6 is the 6th channel of the board #1 (Boolean output)

%ID2.1.7 is the 7th channel of the board #1 in the equipment #2 (integer input)


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The 5 Languages of IEC 61131-3

Instruction List Structured Text Sequential Function Chart

LD A

ANDN B C:= A AND NOT B

Step 1 N FILL

ST C

Transition 1

Function Block Diagram Ladder Diagram Step 2 S Empty

AND

A C

B

A B C

-| |--|/|----------------( )

Transition 2

Step 3


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Ladder Diagram (LD)

 Standardized, rationalized set of relay ladder programming symbols

 Based on well-known US-style of programming, resembling electrical drawing standard

A B C

-| |--|/|----------------( )

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Ladder Diagram (LD)

Ladder Diagram (LD) is a graphic representation of Boolean equations, combining contacts (input arguments) with coils (output results). The LD language enables the description of tests and modifications of Boolean data by placing graphic symbols into the program chart. LD graphic symbols are organized within the chart exactly as an electric contact diagram. LD diagrams are connected on the left side and on the right side to vertical power rails.

A and not B equals C

-| |--|/|----------------( )


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Instruction List (IL)

 Single Accumulator based execution model

 Based upon the German ‘Anweisungsliste’, AWL

 Only one operation such as storing a value in the accumulator register, is allowed per line

LD A

ANDN B

ST C


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Instruction List (IL)

Instruction List, or IL is a low level language. It is highly effective for smaller applications or for optimizing parts of an application. Instructions always relate to the current result (or

IL register).

The processor indicates the operation that must be made between the current value and the operand. The result of the operation is stored again in the current result.

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LD IX1 (* push button *)

ANDN MX5 (* command is not forbidden *)

ST QX2 (* start motor *)





Structured Text (ST)

 High level language, block structured

 Syntax resembles PASCAL

 Complex statements and nested instructions possible

 Support for

• Iteration loops (REPEAT-UNTIL; WHILE-DO)

• Conditional execution (IF-THEN-ELSE; CASE)

• Functions (SQRT(), SIN())

C:= A AND NOT B


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High level language, Syntaxed structured







Syntax resembles traditional programming code such as C++, JAVA, PASCAL

Complex statements and nested instructions possible

Support for

 Iteration loops (REPEAT-UNTIL; WHILE-DO)

 Conditional execution (IF-THEN-ELSE; CASE)

 Advanced Math Functions (SQRT(), SIN())

Applications with complex calculations and data processing examples would involve two phase flow calculations, gas calculations, etc.

C:= A AND NOT B


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Function Block Diagram (FBD)

 Graphical language, widely used in Europe

 Allows program elements which appear as blocks to be

"wired" together in a form analogous to a circuit diagram

 Used in many applications that involve the flow of information or data between control components

AND

A C

B


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Graphical language, widely used in Distributed

Control Systems (DCS) and Analog intensive control systems

 Allows program elements which appear as blocks (Function Blocks) to be connected together in a form analogous to a circuit diagram







Most applications apply to analog control

Used in many applications that involve the flow of information or data between control component

Examples include PID and analog scaling


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AND

A C

B





Sequential Function Chart (SFC)

 Graphical language which provides a diagrammatic representation of program sequences --> flowchart

 Based on the French Grafcet (IEC 848)

 Main structure and suitable for rapid diagnostics

 The basic elements are steps with action blocks and transitions

 Steps consist of a piece of program that is carried out until a condition specified in the transition is met

 Programming of complex tasks by dividing in smaller parts

 Each element can be programmed in any of the

IEC- languages such as LD or ST or IL or FB mix or match any of the languages

Step 1 N FILL

Transition 1

Step 2 S Empty

Transition 2

Step 3


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Technological programming language for describing

Sequential

Controls





Structured program draft





Description of the process with steps and transitions

Clear, easy to understand by the process, production and operations staff

Application examples











Presses and Packaging technology

Production lines

Process technology (start up

– shutdown)

OEM equipment machinery technology

Rotating Machinery e.g. compressors, pumps


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Step 1

Transition

Step 2

Transition

Action 1

Action 2

Action 1





POU = Program Organization Unit

POU’s enable re-use of software from macro level (Programs) to micro level (FB and Functions).

A POU consists of a header (variable declaration) and the body (instructions).

POU Type

Program

Function Block

Function

Replicated as: Comments

Program instance Main program

FB instance Subroutine with own memory, several in - and outputs possible

Function Subroutine without memory

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IEC 61131-3 Standard Datatypes

 Bit string types

 Integer types

(BOOL, BYTE, WORD, DWORD, LWORD)

(SINT, INT, DINT, LINT)

 Unsigned integer types

(USINT, UINT, UDINT, ULINT)

 Real types

(REAL, LREAL)

 Time types

 Character types

(TIME, DATE, TIME_OF_DAY, DATE_AND_TIME)

(STRING)

Vendor and user defined data types are possible

• Direct derived, sub range, enumeration

• Array, structure


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IEC 61131-3 Standard Functions

 Bit string functions (AND, OR, XOR, NOT, SHL, SHR, ROL, ROR)

 Numerical functions (ADD, SUB, MUL, DIV, MOD, EXPT, ABS,

SQRT, LN, LOG, EXP, SIN, COS, TAN, ASIN,

ACOS, ATAN)

 Type conversions (e.g. USINT_TO_DINT, BOOL_TO_BYTE)

 Selection functions (SEL, MIN, MAX, LIMIT, MUX)

 Comparison functions (GT, GE, EQ, LT, LE, NE)

 String functions (LEN, LEFT, RIGHT, MID, CONCAT,

INSERT, DELETE, REPLACE, FIND)

Vendor and user defined functions are possible


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IEC 61131-3 Standard Function Blocks

 Bitable

 Edge detection

 Counters

 Timers

(SR, RS, SEMA)

(R_TRIG, F_TRIG)

(CTU, CTD, CTUD)

(TP, TON, TOF, RTC)

Vendor and user defined function blocks are possible

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PLCopen

Mission

We want to be the leading association resolving topics related to control programming to support the use of international standards in this field.

Page 40 of 38


PLCopen




PLCopen was founded on June 15, 1992 in Giessen, Germany.

Target was to promote IEC 61131-3, inform customers and give more weight to the IEC 61131-3 standard.

PLCopen

Standardization in Industrial

Control programming

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TC6





The Essence of Compliance

without testing there is no standard

 The IEC 61131 standard gives rules for compliancy

 Certification gives guidance for users towards real IEC

61131-3 programming systems (e.g. PLCopen certified list shows compliant products)

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PLCopen Compliance Level

To take away the confusion, PLCopen....

 .... has defined 2 levels of compliance with a defined set of features

 .... has defined an accreditation procedure

 .... has accredited test institutes

 .... developed test software, shared amongst members

 .... has defined a certification procedure

 .... and has members with certified products

This assures compliance now, and in the future.


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PLCopen Compliance Levels

Application

Program

FB

FB

FB

Variable

Variable

Variable

Code

Code

Body

Body

Conformity Level &

Reusability Level

Re-usability of Function (Block) libraries

Base Level

Portability of minimal systems

Application

Program

FB

FB

FB

Variable

Variable

Variable

Code

Code

Body

Body


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Compliance

Certified products can use these logo ’s

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PLCopen Training Logo

Page 46 of 38


Page 47 of 38




PLCopen

www.plcopen.org

P.O. Box 2015

NL 5300 CA Zaltbommel

The Netherlands

Tel: +31-418-541139

Fax: +31-418-516336


Standardization in Industrial Control Programming

PLCopen - IEC 61131 - 3

Overview

What is the IEC 61131 standard ?

IEC 61131 and PLC Open – Mission

PLC Open is a vendor and product independent world-wide organization that brings greater value to users of

Industrial Control Systems through the pursuit of the IEC 61131-3 software development standard

Goals of IEC 61131.3 and PLC Open

Table of contents

Table of contents - continued

Advantages of IEC 61131-3

Advantages of IEC 61131-3

International Language Standardization

The 7 Parts of The IEC 61131 Standard

IEC 61131 - Part 1 - General Overview

IEC 61131 - Part 2 - Hardware

IEC 61131 - Part 3 - Programming

Languages

IEC 61131 - Part 4 User Guidelines

IEC 61131 - Part 5 Communication

IEC 61131 - Part 7 Fuzzy Logic

IEC 61131 - Part 8 Technical Report

IEC 61131-3 Software Model

Definition of Software Model Terms

IEC 61131-3: The Common Elements

The 5 Languages of IEC 61131-3

Ladder Diagram (LD)

Ladder Diagram (LD)

Instruction List (IL)

Instruction List (IL)

Structured Text (ST)

Function Block Diagram (FBD)

Sequential Function Chart (SFC)

Sequential

Controls

POU = Program Organization Unit

IEC 61131-3 Standard Datatypes

IEC 61131-3 Standard Functions

IEC 61131-3 Standard Function Blocks

PLCopen

Mission

We want to be the leading association resolving topics related to control programming to support the use of international standards in this field.

PLCopen

The Essence of Compliance

PLCopen Compliance Level

PLCopen Compliance Levels

Compliance

PLCopen Training Logo

PLCopen

www.plcopen.org

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