BYTE_TO_LREALEX

BYTE_TO_LREALEX 1:

The conversion of unsigned numbers into floating point numbers of the type LREAL is not supported in TwinCAT 2 on the ARM platform. Unsigned numbers with the highest significant bit set may possibly be implicitly converted into negative floating point numbers. The function described here allows the explicit conversion of the type BYTE into a positive floating point number of the type LREAL in TwinCAT 2 (even if the highest significant bit was set and without compiler warning). Unsigned numbers of the type BYTE are always (implicitly and explicitly) converted into positive floating point numbers in TwinCAT3.

FUNCTION BYTE_TO_LREALEX : LREAL

VAR_INPUT
    in      : BYTE;
END_VAR

in: Number to be converted.

Sample:

PROGRAM MAIN
VAR
    nByte  : BYTE := 16#FF;
    fLreal : LREAL := 0.0;
END_VAR

fLreal value	Tc2.x ARM	Tc2.x X86	Tc3.x ARM, X86, X64
`fLreal := nByte`	`+255, Warning 1105*`	`+255`	`+255`
`fLreal := BYTE_TO_LREAL( nByte )`	`+255, Warning 1105*`	`+255`	`+255`
`fLreal := BYTE#16#FF`	`+255, Warning 1105*`	`+255`	`+255`
`fLreal := 16#FF`	`+255`	`+255`	`+255`
`fLreal := BYTE_TO_LREALEX( nByte )`	`+255`	`+255`	`+255`
`fLreal := BYTE_TO_LREALEX( BYTE#16#FF )`	`+255`	`+255`	`+255`
`fLreal := BYTE_TO_LREALEX( 16#FF )`	`+255`	`+255`	`+255`

* Conversion of unsigned integer to LREAL is not supported. The value is used as signed instead.

Requirements

Development environment	Target platform	PLC libraries to be linked
TwinCAT v2.11.0 Build >= 2255	PC or CX (x86, ARM)	TcUtilities.Lib