Data Transmission Using Cyclic I/O S5-95U, SINEC L2
Principle of Operation
A reserved data block (ZP DB) is responsible in the S5-95U for the word-by-word data exchange.
The cyclic I/O input area (ZPE) and cyclic I/O output area (ZPA) for the respective stations are
defined in data block ZP DB.
Figure 7-1. Functional Diagram of Cyclic I/O
Bus
Active
stations
Active/passive
stations
Evaluation of the
received data
Transmit
data
S5-95U
ZP master
ZPA ZPE
ZPE ZPA
Field device
ZP slave
ZPE ZPA
S5-95U
ZP slave
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Explanations to Figure 7-1:
The boxes filled with a pattern represent the data areas (same pattern = same data area).
The user program writes the transmit data to the ZPA of the ZP master
. The transmit data are
transmitted automatically to the respective ZP slaves and written to their ZPE
.
At the same time, the contents of the ZP slave’s ZPA
are transmitted to the corresponding ZPE
of the ZP master
where the user program can evaluate them.
The ZP master creates a ZP slave life list containing all the states of the ZP slaves that the ZP
master scans.
Note
You may read and write the complete ZPA.
You may only read out the ZPE.
7-2
EWA 4NEB 812 6112-02
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