Elementary data types (BOOL, INT, REAL, STRING, etc.)

The EN 61131-3 defines the basic set of data types listed in the table below, including keywords, bit length, range, and initial value.

Keyword Type BitsRange Initial value
BOOL Boolean number
1 0, 1 0
SINT Short integer
8 -128 to 127 0
INT Integer 16 -32768 to 32767 0
DINT Integer, double length
32 -2 147 483 648 to 2 147 483 647 0
LINT Long integer
64 -9223372036854775808 to 9223372036854775807 0
USINT Unsigned short integer
8 0 to 255 0
UINT Unsigned integer
16 0 to 65535 0
UDINT Unsigned integer, double length
32 0 to 4294967295 0
ULINT Unsigned long integer
64 0 to 18446744073709551615 0
REAL Floating point number (single precision)32 -3.40282347E+38 to 3.40282347E+38 (closest to zero is 1.401298E-45) 0.0
LREAL Floating point number (double precision)64 -1.7976931348623157E+308 to 1.7976931348623157E+308 (closest to zero is 4.94065645841247E-324)0.0
TIME Time period duration
64 - T#0s
LTIME Time period duration 64 units: ns T#0s
DATE Date 64 - 1.1.1970 00:00:00
LDATE Date 64 units: ns since 1.1. 1970 LDATE#1970-01-01
TIME_OF_DAY (short: TOD) Time in a day
64 - TOD#00:00:00
LTIME_OF_DAY (short: LTOD) Time in a day 64 units: ns since 1.1. 1970 LTOD#00:00:00
DATE_AND_TIME (short: DT) Absolute time
64 - -
LDATE_AND_TIME (short: LDT)Absolute time 64 units: ns since 1.1. 1970 LDT1970-01-01-00:00:00
STRING String of characters
16 max. 255 characters '' (empty string)
BYTE Sequence of 8 bits 8 16#FF 16#00
WORD Sequence of 16 bits 16 16#FFFF 16#0000
DWORD Sequence of 32 bits 32 16#FFFFFFFF 16#00000000
LWORD Sequence of 64 bits 64 16#FFFFFFFFFFFFFFFF 16#0000000000000000
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