String Conversion¶

Hint

If the operand value for a type conversion operator is outside of the value range of the target data type, then the result output depends on the processor type and is therefore undefined. This is the case, for example, when a negative operand value is converted from LREAL to the target data type UINT.

Information can be lost when converting from larger data types to smaller data types.

The operators convert a character string (STRING or WSTRING) into the specified target data type and return a type-converted value.

A conversion with a meaningful result is only possible when the operand matches the target data type according to the IEC 61131-3 standard. This is the case if the value of the operand corresponds to a valid constant (literal) of the target data type.

Convertible strings contain:

Number with type prefix (example: '16#FFFFFFFF')
Number with grouping characters (example: '2#1111_1111')

Note: The international weight and measure grouping character (thin space) is not accepted. Only the underscore is accepted.
Floating-point number, also in exponential notation (example: '9.876' or '1.2E-34')

Note: Floating-point numbers are not convertible. The comma is treated and truncated like a following character.
Time, time of day, and date specification with prefix and size (example: 'T#2h', 'DT#2019-9-9-12:30:30.9')
Infinite values (example: '1.7E+400')
Additional character after a number (example: '2m' or '3.14'). These are truncated. Additional characters before a number are not permitted.
Spaces before (example: ' 3.14')

Call syntax
Converting to a Boolean value
Examples

Call syntax ¶

<variable name> := <string to operator> ( <operand> );

<operand> = <variable name> | <literal>

Operators

STRING_TO___UXINT
STRING_TO___XINT
STRING_TO___XWORD
STRING_TO_BIT
STRING_TO_BOOL
STRING_TO_BYTE
STRING_TO_DATE
STRING_TO_DINT
STRING_TO_DT
STRING_TO_DWORD
STRING_TO_INT
STRING_TO_LDATE
STRING_TO_LDT
STRING_TO_LINT
STRING_TO_LREAL
STRING_TO_LTIME
STRING_TO_LWORD
STRING_TO_LTIME
STRING_TO_LTOD
STRING_TO_REAL
STRING_TO_SINT
STRING_TO_TIME
STRING_TO_TOD
STRING_TO_UDINT
STRING_TO_UINT
STRING_TO_ULINT
STRING_TO_USINT
STRING_TO_WORD
STRING_TO_WSTRING

WSTRING_TO___UXINT
WSTRING_TO___XINT
WSTRING_TO___XWORD
WSTRING_TO_BIT
WSTRING_TO_BOOL
WSTRING_TO_BYTE
WSTRING_TO_DATE
WSTRING_TO_DINT
WSTRING_TO_DT
WSTRING_TO_DWORD
WSTRING_TO_INT
WSTRING_TO_LDATE
WSTRING_TO_LDT
WSTRING_TO_LINT
WSTRING_TO_LREAL
WSTRING_TO_LTIME
WSTRING_TO_LTOD
WSTRING_TO_LWORD
WSTRING_TO_LTIME
WSTRING_TO_REAL
WSTRING_TO_SINT
WSTRING_TO_STRING
WSTRING_TO_TIME
WSTRING_TO_TOD
WSTRING_TO_UDINT
WSTRING_TO_UINT
WSTRING_TO_ULINT
WSTRING_TO_USINT
WSTRING_TO_STRING
WSTRING_TO_WORD

Converting to a Boolean value ¶

Operator STRING_TO_BOOL: A value of TRUE is returned only if the operand value is 'TRUE' or 'true'. On the other hand, FALSE is returned for 'True'.

Operator WSTRING_TO_BOOL: A value of TRUE is returned only if the operand value is "TRUE" or "true". On the other hand, FALSE is returned for "True".

Examples ¶

ST implementation language

FUNCTION_BLOCK FB_ConvertStrings
VAR_INPUT
END_VAR
VAR_OUTPUT
END_VAR
VAR
        xReturn_0: BOOL;
        xReturn_1: BOOL;
        dateReturn: DATE;
        dtReturn: DATE_AND_TIME;
        iReturn: INT;
        lrReturn: LREAL;
        lrReturn_0: LREAL;
        lwReturn: LWORD;
        lwReturn_0: LWORD;
        lwReturn_1: LWORD;
        ltReturn: LTIME;
        ltReturn_0: LTIME;
        ltReturn_1: LTIME;
        ltReturn_2: LTIME;
        rReturn: REAL;
        rReturn_0: REAL;
        timReturn: TIME;
        timReturn0: TIME;
        timReturn1: TIME;
        timReturn2: TIME;
        todReturn: TIME_OF_DAY;
        todReturn0: TIME_OF_DAY;
        todReturn1: TIME_OF_DAY;
        todReturn2: TIME_OF_DAY;
        uliReurn: ULINT;
        uliReurn_0: ULINT;
        uliReurn_1: ULINT;
        wReturn: WORD;
        wReturn_0: WORD;
        wReturn_1: WORD;
        wstrReturn: WSTRING;
        wstrReturn_0: WSTRING;
END_VAR
xReturn_0 := STRING_TO_BOOL('FALSE');
xReturn_1 := STRING_TO_BOOL('TRUE');
dateReturn := STRING_TO_DATE('DATE#2019-9-9');
dtReturn := STRING_TO_DT('DT#2019-9-9-1:1:1.1');
iReturn := STRING_TO_INT('123abc');
lrReturn := STRING_TO_LREAL('4.94E-323');
lrReturn_0 := STRING_TO_LREAL('1.7E+308');
lwReturn := STRING_TO_LWORD('16#FFFF_FFFF_FFFF_FFFF');
lwReturn_0 := STRING_TO_LWORD('16#0123456789ABCDEF');
lwReturn_1 := STRING_TO_LWORD('16#0123456789ABCDEF');
ltReturn := STRING_TO_LTIME('LTIME#213503d23h34m33s709ms551us615ns');
ltReturn_0 := STRING_TO_LTIME('LTIME#0ns');
ltReturn_1 := STRING_TO_LTIME('LTIME#1ms');
ltReturn_2 := STRING_TO_LTIME('LTIME#2s');
rReturn := STRING_TO_REAL('6.543e21');
rReturn_0 := STRING_TO_REAL('1.234');
timReturn := STRING_TO_TIME('T#5d4h3m2s');
timReturn0 := STRING_TO_TIME('TIME#1s');
timReturn1 := STRING_TO_TIME('1s');
timReturn2 := STRING_TO_TIME('TIME#5s');
todReturn := STRING_TO_TOD('TOD#12:0:0.1');
todReturn0 := STRING_TO_TOD('TOD#0:0:0.0');
todReturn1 := STRING_TO_TOD('20:15');
todReturn2 := STRING_TO_TOD('TOD#20:15');
uliReurn := STRING_TO_ULINT('18446744073709551615');
uliReurn_0 := STRING_TO_ULINT('1');
uliReurn_1 := STRING_TO_ULINT('0');
wReturn := STRING_TO_WORD('16#FFFF_0000');
wReturn_0 := STRING_TO_WORD('34abc');
wReturn_1 := STRING_TO_WORD('16#34abc');
wstrReturn := STRING_TO_WSTRING('Hello World!');
wstrReturn_0 := STRING_TO_WSTRING('123456789');

WSTRING conversion in ST

FUNCTION_BLOCK FB_ConvertWstrings
VAR
        xReturn_0: BOOL;
        xReturn_1: BOOL;
        dateReturn: DATE;
        dtReturn: DATE_AND_TIME;
        iReturn: INT;
        lrReturn: LREAL;
        lrReturn_0: LREAL;
        lwReturn: LWORD;
        lwReturn_0: LWORD;
        lwReturn_1: LWORD;
        ltReturn: LTIME;
        ltReturn_0: LTIME;
        ltReturn_1: LTIME;
        ltReturn_2: LTIME;
        rReturn: REAL;
        rReturn_0: REAL;
        timReturn: TIME;
        timReturn0: TIME;
        timReturn1: TIME;
        timReturn2: TIME;
        todReturn: TIME_OF_DAY;
        todReturn0: TIME_OF_DAY;
        todReturn1: TIME_OF_DAY;
        todReturn2: TIME_OF_DAY;
        uliReurn: ULINT;
        uliReurn_0: ULINT;
        uliReurn_1: ULINT;
        wReturn: WORD;
        wReturn_0: WORD;
        wReturn_1: WORD;
        wstrReturn: WSTRING;
        wstrReturn_0: WSTRING;
END_VAR

xReturn_0 := WSTRING_TO_BOOL("FALSE");
xReturn_1 := WSTRING_TO_BOOL("TRUE");
dateReturn := WSTRING_TO_DATE("DATE#2019-9-9");
dtReturn := WSTRING_TO_DT("DT#2019-9-9-1:1:1.1");
iReturn := WSTRING_TO_INT("123abc");
lrReturn := WSTRING_TO_LREAL("4.94E-323");
lrReturn_0 := WSTRING_TO_LREAL("1.7E+308");
lwReturn := WSTRING_TO_LWORD("16#FFFF_FFFF_FFFF_FFFF");
lwReturn_0 := WSTRING_TO_LWORD("16#0123456789ABCDEF");
lwReturn_1 := WSTRING_TO_LWORD("16#0123456789ABCDEF");
ltReturn := WSTRING_TO_LTIME("LTIME#213503d23h34m33s709ms551us615ns");
ltReturn_0 := WSTRING_TO_LTIME("LTIME#0ns");
ltReturn_1 := WSTRING_TO_LTIME("LTIME#1ms");
ltReturn_2 := WSTRING_TO_LTIME("LTIME#2s");
rReturn := WSTRING_TO_REAL("6.543e21");
rReturn_0 := WSTRING_TO_REAL("1.234");
timReturn := WSTRING_TO_TIME("T#5d4h3m2s");
timReturn0 := WSTRING_TO_TIME("TIME#1s");
timReturn1 := WSTRING_TO_TIME("1s");
timReturn2 := WSTRING_TO_TIME("TIME#5s");
todReturn := WSTRING_TO_TOD("TOD#12:0:0.1");
todReturn0 := WSTRING_TO_TOD("TOD#0:0:0.0");
todReturn1 := WSTRING_TO_TOD("20:15");
todReturn2 := WSTRING_TO_TOD("TOD#20:15");
uliReurn := WSTRING_TO_ULINT("18446744073709551615");
uliReurn_0 := WSTRING_TO_ULINT("1");
uliReurn_1 := WSTRING_TO_ULINT("0");
wReturn := WSTRING_TO_WORD("16#FFFF_0000");
wReturn_0 := WSTRING_TO_WORD("34abc");
wReturn_1 := WSTRING_TO_WORD("16#34abc");

FBD implementation language

String Conversion¶

Call syntax¶

Converting to a Boolean value¶

Examples¶

Call syntax ¶

Converting to a Boolean value ¶

Examples ¶