Siemens SIMATIC S7 Configuration And Programming Manual page 19

You specify the configuration of the following in the object properties dialog of I-
slave 1:
•
to send to I-slave 2, a local address (I-slave 1) and a partner address
(I-slave 2)
•
to receive from I-slave 2, a local address (I-slave 1) and a partner address
(I-slave 2)
No further configuration of communication is necessary in the object properties
dialog of I-slave 2. The addresses are entered automatically in the object
properties dialog of I-slave 2.
You assign the configured addresses to the LADDR parameter of the
corresponding F application blocks F_SENDDP and F_RCVDP in the safety
programs (see Section 1.2.6 and manual, Section 5.4).
Address Areas
Each of the local partner addresses represents a start address of an address area
of input and output data. After configuring the local and partner addresses, the
address areas are automatically assigned. The assigned address areas for a send
and a receive connection are shown in the following table:
Communication
Connection
Send:
I-slave 1 to I-slave 2
Receive:
I-slave 1 from I-slave 2
*
The CPU of the DP master can be an F-CPU or a standard CPU.
Note
We recommend that you use addresses outside the process image as the local
and partner addresses, since the process image should be reserved for the
address areas of modules. When configuring the address areas, the next free
address outside the process image is therefore proposed.
Product Information for the S7 Distributed Safety, Configuring and Programming Manual
A5E00169432-02
Assigned Address Area on the F-CPU* of the ...
I-slave 1: 12 bytes of output and 6 bytes of input data
I-slave 2: 12 bytes of input and 6 bytes output data
DP master: 12 + 6 bytes of input data
I-slave 1: 12 bytes of input and 6 bytes of output data
I-slave 2: 12 bytes of output and 6 bytes of input data
DP master: 12 + 6 bytes of input data
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