BECKHOFF TwinCAT 3 Basics

Training fr Umsteiger

TR3020 | Training for new users | OverviewTwinCAT 3 New Automation Technology

TwinCAT Training: Programmer 29.10.2013 2

Identifier

Indentifier serves to assign individual names to variables, data types, functions, etc.

The identifier starts with a letter or underscore followed by numbers, letters and underscore No distinction is made between upper and lower caseThe following are not permitted special characters (!, , , $, etc.) spaces consecutive underscores umlauts


Keywords

Keywords are identifiers specified by IEC61131-3. They are thus fixed components of the syntax and therefore may not be used for other purposes.

ExamplesStandard operators AND, OR, NOTStandard types BOOL, INT, REAL...Types TYPE, STRUCTBlock types FUNCTION, FUNCTION_BLOCK, PROGRAM


Keywords and comments

The comments are delimited by character strings with (* or *) at the beginning and at the end. Comments may be placed wherever spaces are also permitted. Exception: within string literals.

(*digitale Eingnge*)bStart AT %IX0.0 :BOOL;(*Anlagenstart*)(*analoge Eingnge*)TemK1 AT %IW10 (*Byte 10-11*) :WORD;

Comments to the end of the linebStart AT %IX0.0 :BOOL; // Anlagenstart


Elementary data types

Type Lower Upper Size PrefixBOOL FALSE TRUE x

bBYTE 8 BIT by BitstringWORD 16 BIT w BitstringDWORD 32 BIT dw Bitstring



Typ Lower Upper Gre PrfixSINT -127 127 8 Bit siUSINT 0 255 8 BIT usiINT -32768 32767 16 BIT iUINT 0 65535 16 BIT uiDINT -134 217 728 134 217 727 32 BIT diUDINT 0 4294 967 295 32 BIT udiLINT 64 BIT li

ULINT 0 64 BIT uli

Detail slidesOverflowsExample: EL3102Example: KL2531


Data types 1: Elementary data types

Type Lower Upper Size PrefixTIME_OF_DAY TOD#0:0:0 TOD#23:59:

5932 Bit tod

DATE D#1970:01:01 D#2106 ??? 32 Bit dateDATE_AND_TIME DT#1970:01:01:00:00:00 DT#2106

???32 Bit dt

TIME T#0s T#49d17h2m47s295ms

32BIT tim

Detail slidesDT example - reading the system timeDT example - working with standard operators



Type Lower Upper Size PrefixREAL 4 Byte r

LREAL 8 Byte lr


Data types: STRING

Type Description Example Size PrefixSTRING String in ASCII

code. Standard length 80 characters.Maximum length 255. Strings are zero-terminated

1234ABCDE 80 +1 s

ABCDE$R$LABCDE$0D$0A

String length specificationsExample declaration

Assignment Result SIZEOF Result LEN

sVar : STRING; sVar:=ABC; 81 3sVar1 :STRING(1); sVar := X; 2 1sVar: STRING(255); sVar:=ABC; 256 3


Data types: STRING

Constants $ ASCII Code$0D CR $R $r CR$L $l Line Feed$N $n New Line$T $t Tab

Detail slidesExample: FINDExample: string functions LEN, REPLACEString conversion with Union


Data types: WSTRING

Type Description Example Description Prefix

WSTRING String in Unicode format

Level 0,Block 0x0400-0x4FFFCyrillic

ws

Training, seminar Level 0 Block 0x0000-0x007FBasic Latin


Data types: Examples of literals

Variable Type ExamplesBOOL TRUE 2#1 16#1 1

FALSE 2#0 16#0 0WORD, DWORD

2#1010111111111110 16#AFFE 45054

INT 2#1000000000000001 16#8001 -32768TIME t#1h t#60m t#3600000msd dayh hours t#0.5d t#12h t#43200000msm min

s sec t#30m18s90ms t#0.505025h t#1818090msms ms

REAL 0.3333 3.333e-1


Data types 1: Variable declaration el. data types

A variable possesses a name behind which a value (number, string, date, etc.) is concealed. The variable name is a type of description of the path to the declared data. Variables are characterised above all by the fact that their contents can be changed at runtime.

bStellerUntenLinks:BOOL:=TRUE;

Identifier Data type Initial valueThe physical-logical storage location of this variable is unknown to the user (unlocated)

The degrees of freedom and restrictions in the assignment of the identifiers can be found on the slide entitled Identifiers and Prefixes

Identifier


Data types 1: Located variables

It is possible when declaring a variable to link the name with an address that must be explicitly specified. For the allocation of inputs and outputs of the hardware the incomplete location is to be carried out with I* and Q*

Data type;%IAT

%Q*


Identifier

%M

%Q

%I

Data types 1: Located variables

Completely located variables. AT X

B

W

D

Byte

Byte

Bit

These variables possess a clear address(located)In TwinCAT 3 incompletely located variables can be used for inputs and outputsApplications for %M variables can be solved simply with Unions and direct masking

. Type

Detail slidesDetail - Replace %MB by UNION


Data types 1: Address division

Ain AT%IB0 : INT;IB1 IB0IW0

Ain AT%IW0 : INT;

Din0 AT%IX10.0 : BOOL;IX10.7 IX10.6 IX10.5 IX10.4 IX10.3 IX10.2 IX10.1 IX10.0IB10

Posi AT%IB20 : UDINT;IB23 IB22

Posi AT%ID20 : UDINT;

IB21 IB20IW22 IW20

ID20

equivalent

equivalent

IX22.7 IX22.6 IX22.5 IX22.4 IX22.3 IX22.2 IX22.1 IX22.0

Examples:

BitVar AT%IX22.1 : BOOL;


Data types 1: Variable classes, scope

Local variables are restricted to the block in which they were declared.

KeywordsVAR ..

END_VARVAR_INPUT .. END_VARVAR_IN_OUT ..END_VARVAR_OUTPUT .. END_VAR

KeywordsVAR_GLOBAL .. END_VARVAR_CONFIG .. END_VAR

Global variables are known in each block within a project.


Data types 1: I/O directly in an FB instance

In an FB the inputs and outputs to the periphery are to be created directly as local variables

Implementation


Data types 1: Access via the located variables

The variable locVar locally declared in Program B can be directly accessed from Program A via address %MB2.

PROGRAM AVAR

END_VAR

PROGRAM BVARlocVar AT%MB2:WORD;END_VAR

LD %MB2

Project machine


Data types 1: Overlaps in the scope

As shown on the left, there is an overlap in the scope. In this case the locally declared variable Var1 is loaded into the accumulator. The global variable can also be accessed with Namespaces.

PROGRAM AVAR

Var1 :WORD;END_VAR

LD Var1

LD Gvl1.Var1

Project machine

VAR_GLOBALVar1:WORD;

END_VAR

Example name: Gvl1


Data types 1: PERSISTENT attribute

Special properties of variables can be defined using attributes.

Example:The variable(s) are saved when the PLC is shut down and loaded back on restarting.


Data types 1: Initialisation and CONSTANT

Initial values, the variables are to be preset with a certain value when starting/resetting the PLC.

VAR

AccelerationTime : TIME := T#3s200ms;END_VAR

Read-only:

VAR_GLOBAL CONSTANTpi:REAL:=3.141592654;

END_VARVAR CONSTANT

pi:REAL:=3.141592654;END_VAR

Global

Also locally possible


Data Types 2: Derived data types

The user can create his own data types on the basis of the elementary data types or data types that have already been created. The newly-created data types are visible in the entire project. The declaration starts with TYPE and ends with END_TYPE.

Parent type Name Data type Initial value Area

Derivation Name Data type Initial value Area

InheritanceNew value


Data Types 2: References (alias types)

The purpose of the self-defined data type Reference is to generate an alternative name for a variable, constant or function block. Create your references as objects in the object organiser on the Data Types tab. They start with the keyword TYPE and end with END_TYPE.

Syntax:TYPE

:;END_TYPE

Type

Declaration



Example: A global string variable is transferred to various blocks. If changes are made to the Global Variables, the declarations must also be changed in every block



If a type has been created for the string, further changes are made only to the type


Data Types 2: References (alias types)If a type has been created for the string, further changes are made only to the type



If a type has been created for the string, further changes are made only to the type


Data Types 2: Enumerated type (Enum)An enumerated type is a self-defined data type consisting of a number of string constants. These constants are called enumeration values. The enumeration values are always known in the entire project. It is best to create your enumerated types as objects in the object organiser on the Data Types tab. They start with the keyword TYPEand end with END_TYPE.

Syntax:TYPE :( ,, ...,);END_TYPE

Example:TYPE Woche:(Mo, Di, Mi, Dn, Fr, Sa, So:=10);(*Mo = 0 Di = 1..

.. Sa = 6 So = 10*)END_TYPE

TYPE Richtung:(Up, Dn);(*Up = 0 Dn = 1*)END_TYPE

The same enumeration value can be used twice via Namespace. Example: Woche.Dn Richtung.Dn


Data Types 2: Enumerated type (Enum)Example: signal light without Enum:

Declaration Use

Online


Data Types 2: Enumerated type (Enum)Example: signal light with Enum:

Type

Declaration

Use

Online


Data Types 2: Structure declaration

Example: KL5101 Encoder Terminal Structures are self-defined data types. They are an important aid to better administration of the process data. In addition, the structures are suitable for encapsulated data transfer to function blocks. Structures can be used like individual element variables.


Data Types 2: Structures instancing

ST_KL5101In_1 AT%I* : KL5101_INST_KL5101Out_1 AT%Q* : KL5101_OUT


Data Types 2: ArraysArrays represent lists or data fields. All elements in the arrays are of the same type. Naturally arrays can also consist of own data types (structures).One, two and three-dimensional arrays are possible.

VARFeld_1 :ARRAY[0..9] OF BYTE; 1-dimensionalFeld_2 :ARRAY[0..9, 0..1] OF UINT; 2-dimensionalFeld_3 :ARRAY[0..9, 0..1,0..1] OF DINT; 3-dimensional

END_VARThere is a possibility to place a data field in a directly addressed memory location

VARFeld_1 AT%MB100:ARRAY[1..10] OF BYTE;

END_VARAccess to the sub-elements of a data field

Feld_1[2] := 120; (* Expliziter Zugriff*)Feld_2[i,j] := EXPT(i,j); (*Indizierter Zugriff*)


Data Types 2: Limit transgressions

A dangerous state can arise if an area outside the data field is accessed in the PLC program.

VARFeld_1 :ARRAY[1..10] OF BYTE;Feld_2 :ARRAY[1..10, 2..5] OF UINT;

END_VAR

i:= 9 9Feld_1[i+2] := 120;

Feld_1[9]; 0Feld_2[1,2]; 120


Data Types 2: CheckBounds (FUN)

The access can be monitored by the PLC at PLC runtimeThis function enables a limit transgression occurring in the program to be recognised and rectified.

iMinMax

Limited value

FUNCTION CheckBounds :DINTVAR_INPUT

I,L,U : DINT;END_VAR

IF I< L THEN

CheckBounds := L;ELSIF I > U THEN

CheckBounds := U;ELSE

CheckBounds := I;END_IF

Error case

Error case

OK case


Data Types 2: Adding CheckBounds 1 (FUN)Adding Checkbounds:


Data Types 2: Adding CheckBounds 2 (FUN)


Data Types 2: Method of operation of CheckBounds (FUN)

Example: user error

10

10

source codeCheckbounds is compiled-in in XAR

Do not write, it is called

automatically

(not visible in the code)

Can be checked with call build:


Note about further checker functions

The following further checker functions are possible from TwinCAT 2.8:

Check for division by 0 CheckDivByte CheckDivWord CheckDivDWord CheckDivReal

Check value ranges CheckRangeSigned CheckRangeUnsigned (see appendix)


Data Types 2: Combination: structures and arrays

An array can consist of structures:Structure:TYPE DrillPos :STRUCT

XPos: LREAL;FeedrateX: LREAL;AccelerationX: LREAL;DeccelerationX: LREAL;JerkX: LREAL;YPos: LREAL;FeedrateY: LREAL;AcceleartionY: LREAL;DeccelerationY: LREAL;JerkY: LREAL;FeedDrill: LREAL;Kuehlen: BOOL; (*Pumpe ?*)

END_STRUCTEND_TYPEDeclaration of the array:

Positions :ARRAY[0..100] OF DrillPos;


Data Types 2: Combination: structures and arrays

Access to Drillpos 55:Access:MoveXAx (*FB Instanz*)

(Execute:= TRUE,Position:= Positions[55].XPos ,Velocity:= Positions[55].FeedrateXAcceleration:= Positions[55].AccelerationX,Deceleration:= Positions[55].DeccelerationX,Jerk:= Positions[55].JerkX,Direction:= .........,Axis:= .............,);


Block types

In IEC61131-3 there are three types of block covered by the generic term POU (PROGRAM ORGANISATION UNIT): Program Function Block Function


Block types: program PRG

Program PRG Called by a task (one program can call another) Calls: FBs, functions, (programs) Local variable: static, i.e. the local data are available again in the next cycle. Inputs: usually 0, but VAR_INPUT possible Outputs: usually 0, but VAR_OUTPUT possible Transfer by reference VAR_IN_OUT likewise possible Monitoring: Local data are immediately visible in the online mode of the PLC

control Use: Main programs, Main, Manual, Automatic, etc.


Block types: function block FB

Function block FB Called by programs or other FBs Calls: FBs, functions, Local variable: static, i.e. the local data are available again in the next cycle.

Can be instanced in case of multiple calls (multipliable). Each FB call can have its own local data.

Inputs: 0,1,2,3VAR_INPUT Outputs 0,1,2,3.. VAR_OUTPUT Transfer by reference 0,1,2,3.. VAR_IN_OUT Monitoring: In the online mode of the PLC control the instance of the call

concerned must first be specified. The local data are then visible for each call. Use: multiple-used modules, each of which requires its own data area. Step

chains...


Block types: Function: FC

Function: FC Called by programs, function blocks and other functions Calls: Functions Local variable: temporary, i.e. the local data are available only for the

processing time of the function. Afterwards this data area is used by other functions.

Inputs: 1,2,3........ VAR_INPUT Outputs: precisely 1!, but structure variable possible. The name of

the output is at the same time the name of the function. Transfer by reference 1,2,3........ VAR_IN_OUT , Monitoring: In the online mode of the PLC control only ??? are visible

for the local variables, since this data area is used by all functions in the cycle and monitoring (debug) takes place only at the cycle limits. Remedy: program development with breakpoints

Use: algorithms where the result is available after a run. Scaling, comparison, etc.


ST Structured Text: OperatorsOperation Symbol Binding strengthput in parentheses (expression) Strongest binding

Weakest binding

Function call Function name (parameter list)Exponentiation EXPTNegate -Build. complements NOTMultiply *Divide /Modulo MODAdd +Subtract -Compare ,=Equal to =Not Equal to BOOL AND ANDBOOL XOR XORBOOL OR OR

Same binding strength,processing from left to right(10/2*5 = 25 )

Same binding strength


ST Structured Text: InstructionsInstruction ExampleAssignment:= PosWert := 10;Calling a Function Block Ton1(IN:=Start, PT:=T2s); Output:= Ton1.Q;RETURN RETURN;IF more precise explanations and examples on the

following pagesCASEFORWHILE

REPEAT

EXIT

Empty instruction ;


ST: IF instruction

Is needed to branch in a program, depending on conditions. With the IF instructions its not possible to jump back in the PLC cycle.GOTO is also not available

Keywords:

IF THEN

ELSIFELSEEND_IF


ST: IF instruction

Instruction block

Condition

Yes

No

IF Condition THENInstruction block;

END_IF


ST: IF instruction

IF a>b THENInstruction block A;

ELSEInstruction block B;

END_IF

Condition

Yes

No

Instruction block A Instruction block B


IF Condition1 THENInstruction block A;

ELSEIF Condition2 THEN

Instruction block B;ELSE

IF Condition3 THENInstruction block C;

ELSEInstruction block D;

END_IFEND_IF

END_IF

ST: IF instruction

Instruction block A

Condition 1

YesNo

Instruction block B

Condition 2

YesNo

Condition 3

YesNo

Instruction block C

Instruction block D


IF Condition1 THENInstruction block A;

ELSIF Condition2 THENInstruction block B;

ELSIF Condition3 THENInstruction block C;

ELSEInstruction block D;

END_IF

ST: IF instruction

Instruction block A

Condition 1

YesNo

Instruction block B

Condition 2

YesNo

Condition 3

YesNo

Instruction block C

Instruction block D


ST: IF instruction

What can the BOOLEAN EXPRESSION be?

IF bVar THEN.

IF a>b THEN.

IF LEFT(STR:= strVar, SIZE:=7) = 'TwinCAT' THEN.

IF Ton1.Q THEN.

IF Ton1(IN:=bVar, PT:=T#1s ) THEN

Conditions:

BOOLEAN variable

Comparison

Function calls

Querying of FB instances

NO FB call!


ST CASE Instruction

CASE Selection criterion OF1: Instruction 12, 4, 6: Instruction 27..10: Instruction 3..

ELSE Default instructions

END_CASE;Two identical values may not be available for selection in the list.

Instruction 1

Selection criterion = 1

Yes

No

Instruction 2

Selection criterion = 2 or 4 or 6

Yes

No

YesNo

Instruction 3 Default instructions

Selection criterion = 7 or 8 or 9 or 10?


ST: CASE instruction: possibility for a step chain / state machine

CASE State OF

0: Q0:=TRUE;

IF Transition THEN state := 1; END_IF

1: Q1:=TRUE;


2: Q2:=TRUE;


3: Q3:=TRUE;


END_CASE

Instructions for the step(Actions)

Step-further condition(Transition)


CASE State OF

0: Instructions;(*State=0*)IF THEN

1: Instructions;(*State=1*)



END_CASE

ST: CASE instruction Integer Selector Value with constants

Instructionsif state = 0





ST: CASE instruction Integer Selector Value with Enum types

Enum-Typ:

TYPE Schritte :

(INIT:=0, START, AUTOMATIK, ENDE);END_TYPE

CASE State OF

INIT: Instructions;(*State=0*)START: Instructions;(*State=1*)AUTOMATIK: Instructions;(*State=2*)ENDE: Instructions;(*State=3*)

END_CASE


ST: CASE instruction: suggestion for a step chain / state machine

TYPE Schritte :( INIT:=0, START, AUTOMATIK, ENDE);

END_TYPECASE State OF

INIT: Q0:=TRUE;

IF Transition THEN state := START; END_IF

START: Q1:=TRUE;

IF Transition THEN state := AUTOMATIK; END_IF

AUTOMATIK: Q2:=TRUE;

IF Transition THEN state := ENDE; END_IF

ENDE: Q3:=TRUE;

IF Transition THEN state := INIT; END_IF

END_CASE

Instructions for the step(Actions)

Step-further condition(Transition)

Step


ST: CASE instruction Integer Selector Value with constants

VAR CONSTANTStep1 : INT:= 0;Step2 : INT:= 1;Step3 : INT:= 2;Step4 : INT:= 3;

END_VAR

VAR

State:INT;END_VAR

CASE State OF

Step1: Instructions;(*State=0*)Step2: Instructions;(*State=1*)Step3..Step4: Instructions;(*State=2 oder 3*)

END_CASE


ST: Repeat instructions

The process sequence often requires the multiple processing of precisely the same program sequences, where their number is known only at runtime.Disadvantage of loops:In the case of wrong programming, an infinite number of repetitions takes place.If a continuous loop is executed, this does not impair the start of the time slices (real-time). Tasks with a higher priority will still be executed on time. Tasks with a lower priority will no longer be executed.

1ms 2ms 3ms 4ms 5mse.g.:1 2 3 41 1 11 1

Forced switchover to Win NT

Begin of a new time slice


ST: Loops (overview)

All loops can be terminated with the help of the EXIT instruction, regardless of the abort condition.

Expression Processing n cycle fix

FOR SINT/INT/DINT Instructions follow condition

Yes

WHILE BOOL Instructions follow condition

No

REPEAT BOOL Condition follows instructions

No


ST: FOR loop

At the beginning of the loop the control variable i is set to the starting value (see example). The control variable is decremented or incremented in each loop, depending on the step size (value after the keyword BY). If i exceeds the end value (after TO), the loop is no longer processed.

FOR i:=1 TO 12 BY 2 DOFeld[i]:=i*2;(*Anweisung*)

END_FOR

Cycle n Start i:=StartValue

Instruction block

Cycle n

i>EndValue

Yes

No

i: = i + step size


ST: WHILE loop

The instruction block of a WHILE loop is executed continuously until the Boolean expression returns TRUE. The abort condition can contain variables that can be changed in the instruction block. If the Boolean expression is FALSE at the beginning, then the instruction block of the WHILE loop is not processed.

i:=0;WHILE i


ST: REPEAT loop

The instruction block of a REPEATloop is executed as long as the Boolean expression is satisfied.The instruction block is processed at least once.

i:=0;REPEAT

Feld[i]:=i*2;(*Anweisung*)i:=i+1;

UNTIL i>100END_REPEAT

Boolean expression

Instruction blocki:= i + step size

Cycle n

Cycle n

No

Yes


ST: FB calls in ST

TON1 (IN:= NOT TON1.Q , PT:=T#1s );Q0:= TON1.Q;

VAR

TON1:TON;END_VAR

TON1(IN:= NOT TON1.Q, PT:=T#1s , Q=>Q0 );


ST: FB calls in ST (alternative)

TON1.IN:= NOT TON1.Q; TON1. PT:=T#1s;TON1();Q0:= TON1.Q;

VAR

TON1:TON;END_VAR


ST: FC calls in ST

Result:=Scale (x:=Eingang, xug:=0.0, xog:=32767.0, yug:=0.0,yog:=100.0);(* Gleichwertig:*)Result:=Scale (Eingang, 0.0, 32767.0, 0.0, 100.0);(* Gleichwertig:*)Result:=Scale (

x:= Eingang,xug:= 0.0,

xog:= 32767.0,yug:= 0.0,yog:= 100.0);

In case of functions, all inputs must be occupied


ST: FC calls in ST

Result := Scale (x:=Eingang, xug:=0.0, xog:=32767.0, yug:=0.0,yog:=100.0);

(* Gleichwertig:*)Result:=Scale (

x:= Eingang,xug:= 0.0,xog:= 32767.0,yug:= 0.0,yog:= 100.0);

Result CALL Input parameters

Documents

BECKHOFF TwinCAT 3 Basics