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Addressing/Address Assignments
6.3.1
Accessing the PII
At the beginning of program scanning, the input module signal states are written to the PII. The
statements in the control program use a particular address to indicate what information is
currently needed. The control logic then reads the data that was current at the beginning of pro-
gram scanning and works with it.
Reading bit by bit
in binary operations:
Reading byte by byte
when loading into ACCUM 1:
ACCUM 1
Reading word by word
when loading into
ACCUM 1:
ACCUM 1
Reading of the PII can be inhibited.
To do so, it is necessary to act upon bit 1 of system data word SD 120 (EAF0
operations (Load and Transfer).
Bit 1="1":
Bit 1="0":
The default setting is bit 1="0" (read enabled).
Note
System data word SD 120 can be modified with the programmer function DISPL. ADDR.
only when the PLC is in the STOP mode!
6-8
A I 2.2
L IB 12
15
High-Order
Low-Order
Byte
(Value 00
)
H
L IW 40
15
High-Order
Low-Order
Byte
Figure 6-8. Accessing the PII
Reading of inputs is inhibited.
Reading of inputs is enabled.
PII
7 6 5 4 3 2 1 0
0
Byte
0
Byte
S5-115U Manual
Bit No.
Byte 2
Byte 12
Byte 40
Byte 41
) using system
H
EWA 4NEB 811 6130-02b
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