IEC operator for conversions from the variable type STRING to a different type.
STRING_TO_<data type>
Specify the operand of type STRING matching the IEC61131-3 standard. The value must correspond to a valid constant (literal) of the target type. This applies to the specification of exponential values, infinite values, prefixes, grouping character ("_") and comma. Additional characters after the digits of a number are allowed, as for example, 23xy. Characters preceding a number are not allowed.
The operand must represent a valid value of the target data type.
NOTE: If the data type of the operand does not match the target type, or if the value exceeds the range of the target data type, then the result depends on the processor type and is therefore undefined.
Conversions from larger types to smaller types may result in loss of information.
|
|
|
LOSS OF DATA |
|
When converting mismatched data types or when the value being converted is larger than the target data type, be sure that the result is validated within your application. |
|
Failure to follow these instructions can result in injury or equipment damage. |
|
Example |
Conversion result |
|---|---|
|
LD 'TRUE' |
TRUE |
|
Example |
Conversion result |
|---|---|
|
b := STRING_TO_BOOL('TRUE'); |
TRUE |
|
w := STRING_TO_WORD('abc34'); |
0 |
|
w := STRING_TO_WORD('34abc'); |
34 |
|
t := STRING_TO_TIME('T#127ms'); |
T#127ms |
|
r := STRING_TO_REAL('1.234'); |
1.234 |
|
bv := STRING_TO_BYTE('500'); |
244 |
|
Example |
Conversion result |
|---|---|
|
TRUE |
