REAL/LREAL
The data types REAL and LREAL are floating-point types according to IEEE 754. They are necessary for the use of decimal numbers and floating-point numbers in point representation or exponential representation.
Data type | Lower limit | Upper limit | Smallest absolute value | Storage space |
|---|---|---|---|---|
REAL | -3.402823e+38 | 3.402823e+38 | 1.0e-44 | 32-bit |
LREAL | -1.7976931348623158e+308 | 1.7976931348623158e+308 | 4.94065645841247e-324 | 64-bit |
Sample
PROGRAM MAIN
VAR
fMaxReal : REAL := 3.402823E+38; // Largest REAL number
fPosMinReal : REAL := 1.0E-44; // Smallest positive REAL number
fNegMaxReal : REAL := -1.0E-44; // Largest negative REAL number
fMinReal : REAL := -3.402823E+38; // Smallest REAL number
fMaxLreal : LREAL := 1.7976931348623157E+308; // Largest LREAL number
fPosMinLreal : LREAL := 4.94065645841247E-324; // Smallest positive LREAL number
fNegMaxLreal : LREAL := -4.94065645841247E-324; // Largest negative LREAL number
fMinLreal : LREAL := -1.7976931348623157E+308; // Smallest LREAL number
END_VAR | If the value of the REAL/LREAL number lies outside of the value range of the integer, an undefined result will be delivered when converting the data type from REAL or LREAL to SINT, USINT, INT, UINT, DINT, UDINT, LINT or ULINT. |
| Allocation of a particularly large literal In order to assign an integer literal that is larger than the upper limit of ULINT, either a comma must be set or an explicit typecast must be specified. Without such a specification as a floating-point number, information can be lost. |
See also: