Swap Byte (SWPB)
The SWPB instruction rearranges the order of the bytes of the Source. It places the result in the Destination.
Available Languages
Ladder Diagram
_v1.png/_jcr_content/renditions/original)
FactoryTalk Design Studio
DSL - Ladder DiagramSWPB(Source, Order Mode, Dest);
Operands
IMPORTANT:
Unexpected operation may occur if:
- Output tag operands are overwritten
- Members of a structure operand are overwritten
- Except when specified, structure operands are shared by multiple instructions.
There are data conversion rules for mixing numeric data types within an instruction. See Data Conversion.
Ladder Diagram
Operand | Data Type | Format | Description |
|---|---|---|---|
Source | INT DINT | tag | Tag that contains the bytes to rearrange. |
Order Mode | list item | This operand specifies how to reorder. Refer Order Mode table. | |
Dest | INT DINT | tag | Tag to store the bytes in a new order. Refer Dest table. |
If selecting the HIGH/LOW order mode, enter it as HIGHLOW (without the slash).
Order Mode
If the Source is an | And you want to change the bytes to this pattern(each letter represents a different byte) | Then select |
|---|---|---|
INT | AB => BA | Any option |
DINT | ABCD => DCBA | REVERSE |
ABCD =>CDAB | WORD | |
ABCD => BADC | HIGH/LOW |
Dest
If the Source is an | Then the Destination must be an |
|---|---|
INT | INT, DINT If the destination is a DINT, the result is sign extended after bytes swap. |
DINT | DINT |
Affects Math Status Flags
No
Major/Minor Faults
None specific to this instruction. See Index through arrays for array-indexing faults.
Execution
Ladder Diagram
Condition/State | Action Taken |
|---|---|
Prescan | N/A |
Rung-condition-in is false | N/A |
Rung-condition-in is true | The instruction rearranges the specified bytes. |
Postscan | N/A |
Examples
Example 1 - Swap the bytes of a DINT tag
The three SWPB instructions reorder the bytes of DINT_1 according to a different order mode. The display style is ASCII, and each character represents one byte. Every instruction places the bytes, in the new order, in a different Destination.
Ladder Diagram
Example 2 - Swap the bytes in all elements of an array
Ladder Diagram
Provide Feedback