Siemens SIMATIC S5-115U, User Manual

Page: 212 / 676

STEP 5 Operations S5-115U Manual
Load Operation:
During loading, information is copied from a memory area, e.g., from the PII, into ACCUM 1.
The previous contents of ACCUM 1 are shifted to ACCUM 2.
The original contents of ACCUM 2 are lost.
Example: Two consecutive bytes (IB 7 and IB 8) are loaded from the PII into the accumulator.
Loading does not change the PII (see Figure 8-2).
Figure 8-2. Execution of the Load Operation
Byte a
Byte c
L IW 8
L IB 7
Informationen
from the PII Lost
information
0 IB 7
ACCUM 2 ACCUM 1
Byte b
Byte d IB 7
Byte d Byte c Byte a
Byte b IB 7 0
Byte b
Byte a
IB 8 IB 9 IW 8
Transfer Operation:
During transfer, information from ACCUM 1 is copied into the addressed memory area, e.g., into
the PIQ.
This transfer does not affect the contents of ACCUM 1.
When transfer to the digital output area occurs, the byte or word in question in the PIQ is
automatically updated.
Example: Figure 8-3 shows how byte a, the low byte in ACCUM 1, is transferred to QB 5.
Figure 8-3. Transferring a Byte
T QB 5
Information
in the PIQ Lost
informationen ACCUM 2 ACCUM 1
Byte d Byte c Byte a
Byte d
Byte b
Byte c Byte a Byte a Byte b
Previous value
of QB 5
8-12
EWA 4NEB 811 6130-02b