Siemens S7-1200 - SWAP (Swap Bytes) Instruction

Basic instructions
7.6 Move operations
S7-1200 Programmable controller
System Manual, 03/2014, A5E02486680-AG
243
The FILL_BLK and UFILL_BLK instructions copy the source data element IN to the
destination where the initial address is specified by the parameter OUT. The copy process
repeats and a block of adjacent addresses is filled until the number of copies is equal to the
COUNT parameter.
FILL_BLK and UFILL_BLK instructions differ in how interrupts are handled:
● Interrupt events are
queued and processed
during FILL_BLK execution. Use the
FILL_BLK instruction when the data at the move destination address is not used within an
interrupt OB subprogram or, if used, the destination data does not have to be consistent.
● Interrupt events are
queued but not processed
until UFILL_BLK execution is complete.
Use the UFILL_BLK instruction when the move operation must be completed and the
destination data consistent, before the execution of an interrupt OB subprogram.
Table 7- 70 ENO status
ENO
Condition
Result
1 No error The IN element was successfully copied to
all COUNT destinations.
0 The destination (OUT) range exceeds
the available memory area
Elements that fit are copied. No partial
elements are copied.
7.6.4
SWAP (Swap bytes) instruction
Table 7- 71 SWAP instruction
LAD / FBD
SCL
Description
out := SWAP(in);
Reverses the byte order for two-byte and four-byte data elements. No change
is made to the bit order within each byte. ENO is always TRUE following
execution of the SWAP instruction.
1
For LAD and FBD: Click the "???" and select a data type from the drop-down menu.