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IronPLC supports IEC 61131-3 Structured Text excluding I/O mapping.

Data Types

IEC 61131-3 defines a set of elementary data types and mechanisms for creating derived types.

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Examples on supported data type pages are interactive — edit the code and see results in your browser. Powered by the IronPLC Playground.

Elementary Types

Type	Size	Description
BOOL	1 bit	Boolean
SINT	8 bits	Signed short integer
INT	16 bits	Signed integer
DINT	32 bits	Signed double integer
LINT	64 bits	Signed long integer
USINT	8 bits	Unsigned short integer
UINT	16 bits	Unsigned integer
UDINT	32 bits	Unsigned double integer
ULINT	64 bits	Unsigned long integer
REAL	32 bits	Single-precision floating point
LREAL	64 bits	Double-precision floating point
BYTE	8 bits	Bit string of 8 bits
WORD	16 bits	Bit string of 16 bits
DWORD	32 bits	Bit string of 32 bits
LWORD	64 bits	Bit string of 64 bits
STRING	Variable	Single-byte character string
WSTRING	Variable	Double-byte character string
TIME	32 bits	Duration
LTIME	64 bits	Duration (Edition 3)
DATE	32 bits	Calendar date
LDATE	64 bits	Calendar date (Edition 3)
TIME_OF_DAY	32 bits	Time of day
LTIME_OF_DAY	64 bits	Time of day (Edition 3)
DATE_AND_TIME	64 bits	Date and time of day
LDATE_AND_TIME	64 bits	Date and time of day (Edition 3)

Derived Types

Type	Description
Enumerated types	Named set of values
Subrange types	Integer type restricted to a range
Array types	Fixed-size indexed collection
Structure types	Record with named fields
Reference types	Pointer to a variable (Edition 3)