Equipments (Devices) > SCA06 > Ladder > Data Transfer

Block that rearranges the bytes of a variable.

Ladder Representation

SWAP2_block

Block Structure

Variable type	Name	Data type	Description
VAR_INPUT	EN	BOOL	Block enabling
	Value	WORD UINT INT DWORD UDINT DINT	Input variable to be rearranged
	Type	BYTE	Variable that defines the conversion type according to Table 2
VAR_OUTPUT	ENO	BOOL	End of operation
VAR_OUTPUT	Result	BYTE USINT SINT WORD UINT INT DWORD UDINT DINT REAL(*)	Output value

Table 1. Block variables.

Type	WORD UINT INT	ENO	DWORD UDINT DINT	ENO
0	AB->AB*	TRUE	ABCD->ABCD	TRUE
1	AB->BA	TRUE	ABCD->DCBA	TRUE
2	-	FALSE	ABCD->CDAB	TRUE
3	-	FALSE	ABCD->BADC	TRUE
4 ...	-	FALSE	-	FALSE

Table 2. Conversion type (*characters A, B, C and D represents BYTES).

Operation

When this block has a TRUE value in EN, it rearranges the bytes from Value variable, storing the result in Result.

Type defines how the bytes will be rearranged, as shown in Table 2.

Note that for 16-bit variables, only options 0 and 1 are valid.

For 32-bit variables the options 0, 1, 2, and 3 are valid.

When EN has FALSE value, Result remains unchanged.

The ENO value forwards to the next Ladder block the EN value after the operation is completed. Invalid TYPE options assigns FALSE to ENO, and Result value is not changed.

NOTA!

Caution when using in Result a variable of REAL type, because the block does not perform type conversion, that is, it only reverses the bytes in memory.

Block Flowchart

SWAP2_flowchart

Example in Ladder

SWAP2_example01

The example rearranges the position of value VALUE_IN according to the type set in TYPE_IN = 1 (AB->BA), storing the final result in RESULT. The block ends with success and ENO output is activated.

Example in ST

The example below displays the instructions for applying the example above in the ST language.

VAR

VALUE_IN : INT := 16#2501;

TYPE_IN : BYTE := 1;

RES_OUT : INT;

END_VAR

RES_OUT := FB_SWAP2(

EN:=DI1,

Value:=VALUE_IN,

Type:=TYPE_IN,

ENO=>DO1);