Integers and Bit strings

Description

Integers and bit strings are first defined by the number of bytes they consume. Secondly, they are described by what they represent. Integers are signed (representing positive and negative values) or unsigned (only positive values inclusive of 0). A bit string BYTE / WORD / DWORD / LWORD represents a collection of bits.

Data Type	Bytes	Minimum Value	Maximum Value
BYTE	1	16#0	16#ff
USINT	1	0	255
SINT	1	-128	127
WORD	2	16#0	16#ffff
UINT	2	0	65535
INT	2	-32768	32767
DWORD	4	16#0	16#ffff_ffff
UDINT	4	0	4,294,967,295
DINT	4	-2,147,483,648	2,147,483,647
LWORD	8	16#0	16#ffff_ffff_ffff_ffff
ULINT	8	0	18,446,744,073,709,551,615
LINT	8	-9,223,372,036,854,775,808	9,223,372,036,854,775,807

Declaration

Number Systems

The following number systems are supported as described by the IEC 61131-3 standard.

Number System	Base	Represented by
Binary	2	0 / 1
Octal	8	0 through 7
Decimal	10	0 through 9
Hexadecimal	16	0 through 9, A through F

Literals

There are many methods for assigning integer literal values.

a : INT;

// Use the 2# prefix to indicate binary number system
a := 2#10;
print(a);
printf(a, 'b2');

// Use the 8# prefix to indicate the octal number system
a := 8#107;
print(a);           // NOTE : currently no formatter for octal numbers in printf function


// Standard decimal number system
a := -10;
print(a);

// Use the 16# prefix to indicate the hexadecimal number system
a := 16#A;
print(a);
printf(a, 'x');

For large numbers it can help to use the underscore _ character to provide some separation. Note that commas are not allowed within the literals.

a : INT;

a := 2#01001000_11001111;
a := -32_768;