TO_WORD block
Short summary
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Name |
TO_WORD |
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→POU type |
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Category |
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Conform to →IEC-standard |
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Graphical interface |
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Available since |
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more possible than defined in IEC-standard 
Functionality
The blocks serves for explicitly converting the value connected to input IN into a value of data type WORD.
If the connected value is within the range of values overlapping for the data type of the input and for the result value WORD, the blocks returns this value.
Observe:
If a negative value of data type REAL or LREAL is connected to the input, the blocks returns the value 0. If a negative value of a different data type is connected, the block returns a value according to the data type of the return value.
If converting data types to the TIME data type and vice versa, the conversion is always based on seconds.
If a value of data type STRING is connected to the input, the value is converted to a decimal value (base: 10, allowed digits: 0 to 9) and then this decimal value is converted to a value according to the target data type . The following special cases might occur (see under "Example for usage within ST-editor" ) :
If the value starts with the character + , with blanks or tabs (= so-called whitespace) and the value is within the range of values for the target data type, the value is converted to a positive decimal value (without these characters). In this case, the output ENO is set to value TRUE .
Details on this conversion: The character + as prefix for the value is ignored, blanks and tabs (= so-called whitespace) are ignored as well.If the value starts with the character – and the value is within the range of values for the target data type, the value is converted analogously to a connected, negative INT value. In this case, the output ENO is set to value TRUE as well.
Details on this conversion: The upper limit of the target data type is converted to the positive decimal value, this decimal value is increased by the value 1 and then the STRING value (in fact the corresponding decimal value) is subtracted. The result is converted to a value appropriate to the target data type.If the value contains an invalid character, the block returns the value 0. In this case, the output ENO is set to value FALSE .
Valid characters
invalid characters
digits (base: 10, numbers: 0 to 9)
Example for value with valid character: '7'other characters such as letters
Example for value with invalid character: '12a3', 'a123'one character + or – as a prefix of the value
Example for value with valid character: +2 or –3repetitions of + or – at the beginning of the value, the character + or – within the value
Example for value with invalid character: '++1', '1–3'single underscore characters _ within the value
Example for value with valid character: 1_2 or 1_2_3underscore character _ at the beginning or the end of the value, several characters _ behind one another
Example for value with invalid character: _12, 12_ or 1__2If the STRING value to be converted exceeds the upper limit of the target data type, the block returns the upper limit of the target data type. In this case, the output ENO is set to value FALSE as well.
If a value of data type CHAR is connected to the input, the conversion is analogous to a STRING value. But different to the STRING conversion, the CHAR conversion supports single digits digits 0 to 9 only. For all other characters (letters, the characters +, - and _), the block returns the value 0 and the output ENO is set to value FALSE .
Explicit conversion according to IEC-standard
The IEC-standard defines an explicit conversion of the following data types to WORD:
LINT, DINT, INT, SINT, ULINT, UDINT, UINT, USINT, LWORD, DWORD, BYTE, BOOL
The IEC-standard (Edition 3.0) defines a binary transfer for the following data types of the input . But contrary to this, the appropriate value is converted according to the IEC-standard (Edition 2.0).
SINT
Inputs, return value
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Identifier |
Description |
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Inputs: |
IN |
REAL, LREAL, USINT, UINT, UDINT, ULINT, SINT, INT, DINT, LINT, TIME, BOOL, BYTE, WORD, DWORD, LWORD, STRING, CHAR or TIME_OF_DAY |
value to be converted |
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Return value: |
– |
WORD |
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Input EN and output ENO are available when →calling the block. See "Execution control: EN, ENO" for information on input EN and output ENO.
Internal error diagnostic for block
The block checks the value connected to the input. The output ENO of the block is set to value FALSE (or an equivalent) in the following cases:
A STRING value contains an invalid character. (Moreover for this case, the block returns the value 0.)
A STRING value exceeds the upper limit of the target data type. (Moreover for this case, the block returns the upper limit of the target data type.)
The CHAR value is an invalid character. (Moreover for this case, the block returns the value 0.)
Example for usage within ST-editor
The calculated values are evaluated by using the Assert block .
FUNCTION_BLOCK ExampleToWord VAR result : WORD; END_VAR result := TO_WORD(IN := DINT#12); Assert(result = 16#000C); END_FUNCTION_BLOCKFUNCTION_BLOCK ExampleToWordString VAR resultStr1, resultStr2, resultStr3, resultStr4, resultStr5, resultStr6, resultStr7, resultStr8, resultStr9, resultStr10, resultStr11, resultStr12, resultStr13, resultStr14 : WORD; CheckENO1, CheckENO2, CheckENO3, CheckENO4, CheckENO5, CheckENO6, CheckENO7, CheckENO8, CheckENO9, CheckENO10, CheckENO11, CheckENO12, CheckENO13, CheckENO14 : BOOL; END_VAR resultStr1 := TO_WORD(IN:='12', ENO=>CheckENO1); Assert(resultStr1 = 16#000C); Assert(CheckENO1 = TRUE); resultStr2 := TO_WORD(IN:=' 3', ENO=>CheckENO2); Assert(resultStr2 = 16#0003); Assert(CheckENO2 = TRUE); resultStr3 := TO_WORD(IN:='+2', ENO=>CheckENO3); Assert(resultStr3 = 16#0002); Assert(CheckENO3 = TRUE); resultStr4 := TO_WORD(IN:='-3', ENO=>CheckENO4); Assert(resultStr4 = 16#FFFD); Assert(CheckENO4 = TRUE); resultStr5 := TO_WORD(IN:='1_2', ENO=>CheckENO5); Assert(resultStr5 = 16#000C); Assert(CheckENO5 = TRUE); resultStr6 := TO_WORD(IN:='1_2_3', ENO=>CheckENO6); Assert(resultStr6 = 16#007B); Assert(CheckENO6 = TRUE); resultStr7 := TO_WORD(IN:='123a45', ENO=>CheckENO7); Assert(resultStr7 = 16#0000); Assert(CheckENO7 = FALSE); resultStr8 := TO_WORD(IN:='a1234', ENO=>CheckENO8); Assert(resultStr8 = 16#0000); Assert(CheckENO9 = FALSE); resultStr9 := TO_WORD(IN:='++1', ENO=>CheckENO9); Assert(resultStr9 = 16#0000); Assert(CheckENO9 = FALSE); resultStr10 := TO_WORD(IN:='1-3', ENO=>CheckENO10); Assert(resultStr10 = 16#0000); Assert(CheckENO10 = FALSE); resultStr11 := TO_WORD(IN:='_12', ENO=>CheckENO11); Assert(resultStr11 = 16#0000); Assert(CheckENO11 = FALSE); resultStr12 := TO_WORD(IN:='12_', ENO=>CheckENO12); Assert(resultStr12 = 16#0000); Assert(CheckENO12 = FALSE); resultStr13 := TO_WORD(IN:='1__2', ENO=>CheckENO13); Assert(resultStr13 = 16#0000); Assert(CheckENO13 = FALSE); resultStr14 := TO_WORD(IN:='70000', ENO=>CheckENO14); (* The upper limit for WORD is 16#FFFF. This evaluates to the decimal value 65.535. *) Assert(resultStr14 = 16#FFFF); Assert(CheckENO14 = FALSE); END_FUNCTION_BLOCKWhen creating your application within the ST-editor, enter a call of a block by typing the text as requested by the syntax or use Content Assist.