Elementary Data Types according to IEC 61131-3

Data type 1 Size in bits Range Default initial value

BOOL Boolean 1 TRUE / FALSE FALSE

SINT Short integer 8 -128 to 127 0

INT Integer 16 -32,768 to 32,767 0

DINT Double integer 32 -2,147,483,648 to 2,147,483,647 0

LINT Long integer 64 -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807 0

USINT Unsigned short integer 8 0 to 255 0

UINT Unsigned integer 16 0 to 65,535 0

UDINT Unsigned double integer 32 0 to 4,294,967,295 0

ULINT Unsigned long integer 64 0 to 18,446,744,073,709,551,615 0

REAL Real numbers 32 -3.402823466 E+38 (approx. 7 digits)
to
-1.175494351 E-38 (approx. 7 digits)
and
+1.175494351 E-38 (approx. 7 digits)
to
+3.402823466 E+38 (approx. 7 digits)
See the note below the table concerning REAL and LREAL processing. 0.0

LREAL Long real numbers 64 ~ -1.798 E+308 (approx. 15 digits)
to
~ -2.225 E-308 (approx. 15 digits)
and
~ +2.225 E-308 (approx. 15 digits)
to
~ +1.798 E+308 (approx. 15 digits)
See the note below the table concerning REAL and LREAL processing. 0.0

TIME Duration 32 -24d20h31m23s648ms up to 24d20h31m23s647ms t#0s

LTIME Long duration 64 - 106751d23h47m16s854ms775us808ns up to +106751d23h47m16s854ms775us807ns LTIME#0ns

BYTE Bit string of length 8 8 0 to 255
(16#00...16#FF) 0

WORD Bit string of length 16 16 0 to 65,535
(16#00...16#FFFF) 0

DWORD Bit string of length 32 32 0 to 4,294,967,295
(16#00....16#FFFFFFFF) 0

LWORD Bit string of length 64 64 0 to 18,446,744,073,709,551,615
(16#00....16#FFFFFFFFFFFFFFFF) 0

LDATE / LD Long date 64 min. : 1677-09 -22
max. : 2262-04-11 LDATE#1970-01-01

LTIME_OF_DAY / LTOD Long time of day 64 min. : 00:00:00.0
max. : 23:59:59.999999999
See the note below the table concerning LTOD processing. LTOD#00:00:00

LDATE_AND_TIME / LDT Long date with time of day 64 min. : 1677-09-21-00:12:43.145224192
max. : 2262-04-11-23:47:16.854775807 LDT#1970-01-01-00:00:00

Data type	1	Size in bits	Range	Default initial value
BOOL	Boolean	1	TRUE / FALSE	FALSE
SINT	Short integer	8	-128 to 127	0
INT	Integer	16	-32,768 to 32,767	0
DINT	Double integer	32	-2,147,483,648 to 2,147,483,647	0
LINT	Long integer	64	-9,223,372,036,854,775,808 to 9,223,372,036,854,775,807	0
USINT	Unsigned short integer	8	0 to 255	0
UINT	Unsigned integer	16	0 to 65,535	0
UDINT	Unsigned double integer	32	0 to 4,294,967,295	0
ULINT	Unsigned long integer	64	0 to 18,446,744,073,709,551,615	0
REAL	Real numbers	32	-3.402823466 E+38 (approx. 7 digits) to -1.175494351 E-38 (approx. 7 digits) and +1.175494351 E-38 (approx. 7 digits) to +3.402823466 E+38 (approx. 7 digits) See the note below the table concerning REAL and LREAL processing.	0.0
LREAL	Long real numbers	64	~ -1.798 E+308 (approx. 15 digits) to ~ -2.225 E-308 (approx. 15 digits) and ~ +2.225 E-308 (approx. 15 digits) to ~ +1.798 E+308 (approx. 15 digits) See the note below the table concerning REAL and LREAL processing.	0.0
TIME	Duration	32	-24d20h31m23s648ms up to 24d20h31m23s647ms	t#0s
LTIME	Long duration	64	- 106751d23h47m16s854ms775us808ns up to +106751d23h47m16s854ms775us807ns	LTIME#0ns
BYTE	Bit string of length 8	8	0 to 255 (16#00...16#FF)	0
WORD	Bit string of length 16	16	0 to 65,535 (16#00...16#FFFF)	0
DWORD	Bit string of length 32	32	0 to 4,294,967,295 (16#00....16#FFFFFFFF)	0
LWORD	Bit string of length 64	64	0 to 18,446,744,073,709,551,615 (16#00....16#FFFFFFFFFFFFFFFF)	0
LDATE / LD	Long date	64	min. : 1677-09 -22 max. : 2262-04-11	LDATE#1970-01-01
LTIME_OF_DAY / LTOD	Long time of day	64	min. : 00:00:00.0 max. : 23:59:59.999999999 See the note below the table concerning LTOD processing.	LTOD#00:00:00
LDATE_AND_TIME / LDT	Long date with time of day	64	min. : 1677-09-21-00:12:43.145224192 max. : 2262-04-11-23:47:16.854775807	LDT#1970-01-01-00:00:00

Note
If you are using PLCnext Engineer in another user interface language and/or with another Windows system locale than English you must enter numeric values with a '.' as decimal separator (always according to the English standard). This applies, for example, when entering initial values in variables tables or REAL/LREAL literals in the code.

Note
Processing of REAL and LREAL data types
There is a limited accuracy when processing REAL and LREAL data types. This is caused by the characteristics of the processor architecture and the data type definition according to IEEE. This applies to the positive and also the negative value range.

Note
Processing of LTOD data type
In the event of an overflow (min or max value for the LTOD data type exceeded), the LTOD value is interpreted and displayed as time value in nanoseconds ("xxxxx ns").

Data types STRING and WSTRING
The data types STRING (single byte string) and WSTRING (double byte string) are also elementary data types but do not belong to the above mentioned group. The data types STRING and WSTRING have the following structure:

Byte Description

STRING data type

0...1 Capacity - Maximum number of characters that the string can hold (from 0 to UINT16.MAX).

2...3 Length - Current number of characters in the string (from 0 to Capacity).

4...84
(for an 80 characters string)
4...124
(for a user-defined string of 120 characters) String of ANSI characters followed by a trailing zero character. Each character is represented by one byte.

WSTRING data type

0-1 Capacity - Maximum number of characters that the string can hold (from 0 to UINT16.MAX).

2-3 Length - Current number of characters in the string (from 0 to Capacity).

4...165
(for an 80 characters string)
4...245
(for a user-defined string of 120 characters) String of UTF16 characters followed by a trailling zero character. Each character is represented by two bytes or, for some language characters, by four bytes.

Byte	Description
STRING data type
0...1	Capacity - Maximum number of characters that the string can hold (from 0 to UINT16.MAX).
2...3	Length - Current number of characters in the string (from 0 to Capacity).
4...84 (for an 80 characters string) 4...124 (for a user-defined string of 120 characters)	String of ANSI characters followed by a trailing zero character. Each character is represented by one byte.
WSTRING data type
0-1	Capacity - Maximum number of characters that the string can hold (from 0 to UINT16.MAX).
2-3	Length - Current number of characters in the string (from 0 to Capacity).
4...165 (for an 80 characters string) 4...245 (for a user-defined string of 120 characters)	String of UTF16 characters followed by a trailling zero character. Each character is represented by two bytes or, for some language characters, by four bytes.