ROL block

Short summary

Name	`ROL`
→POU type	→function
Category	Standard (safe), Bitstring
Conform to →IEC-standard	currently restricted (IEC demands data type `ANY_INT` for the input`N` and an error handling in case of values < `0` for input `N`.)
Graphical interface
Available since	version 1.18.0 (for Neuron Power Engineer) - initial variant version 3.8.0 (for library `Standard (safe)`): block provided in this library

Functionality

The block returns the result of a bitwise rotation to the left (circular).

At input IN, enter the value to be rotated. At input N, enter the bits to left-rotate the value. The bits cleared on the one side are filled in on the other side.

Deviation from IEC-standard

If a negative value is connected to the input N, Neuron Power Engineer does not treat this as an error but performs an opposite rotation, hence a rotation to the right. This behavior is a deviation from the →IEC-standard that specifies that values < 0 for the input N are an error.

Inputs, return value

	Identifier	→Data type	Description
Inputs:	`IN`	`BOOL`, `BYTE`, `WORD`, `DWORD` or `LWORD` (corresponds to →generic data type `ANY_BIT`)	input value
Inputs:	`N`	`INT`	number of bits to rotate
Return value:	–	`BOOL`, `BYTE`, `WORD`, `DWORD` or `LWORD` (corresponds to →generic data type `ANY_BIT`)

Input EN and output ENO are available when →calling the block. See "Execution control: EN, ENO" for information on input EN and output ENO.

See:

"Blocks for safe logic" whether this block is supported for developing safety-relevant applications.
"Highlighting safe logic in the FBD-editor" for the effects when using the block as a block for safe logic.

Example for usage within ST-editor

PROGRAM Test

VAR

        result1 : BYTE;

        result2 : WORD;

    END_VAR

    result1 := ROL(IN := BYTE#16#42, N := 2);  (* The variable 'result1' evaluates to '16#09' (decimal: 9). *)

    result2 := ROL(IN := WORD#16#42, N := 2);  (* The variable 'result2' evaluates to '16#0108' (decimal: 264). *)

END_PROGRAM

When creating your application within the ST-editor, enter a call of a block by typing the text as requested by the syntax or use Content Assist.