Siemens SIMATIC S5-95F - Page 192

STEP 5 Operations S5-95F
Load Operation
During loading, information is copied from a memory area, e.g., from the PII, into ACCU 1.
The previous contents of ACCU 1 are shifted to ACCU 2.
The original contents of ACCU 2 are lost.
Example: Two consecutive bytes (IB7 and IB8) 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 IB 8
L IB 7
Information
from the PII
Lost
information
0 IB 7
ACCU 2 ACCU 1
Byte b
Byte d IB 7
Byte d Byte c Byte a
Byte b IB 70
Byte b
Byte a
0 IB 8 IB 8
Transfer Operation
During transfer, information from ACCU 1 is copied into the addressed memory area, e.g., into the
PIQ.
This transfer does not affect the contents of ACCU 1.
Example: Figure 8-3 shows how byte a, the low byte in ACCU 1, is transferred to QB5.
Figure 8-3. Transferring a Byte
T QB 5
Information
in the PIQ
Lost
information
ACCU 2 ACCU 1
Byte d Byte c Byte a
Byte d
Byte b
Byte c Byte aByte aByte b
Previous value
of QB5
8-12 EWA 4NEB 812 6210-02