Addressing Interface In Step 7 V5.1 (Extract) - Siemens SIMATIC IM 151/CPU Manual

Addressing
Rules for Address Allocation
You must comply with the following rules when allocating addresses for the
ET 200S with the IM 151/CPU:
Assignment of the address areas:
– Input data for the ET 200S is always output data for the DP master
– Output data for the ET 200S is always input data for the DP master
You access the data in the user program using load/transfer instructions or
SFCs 14 and 15.
The length, unit and consistency of the associated address areas for the DP
master and the DP slave must be identical.
Addresses for the master and the slave can be different in the logically identical
intermediate memory (mutually independent logical I/O address areas in the
master and the slave CPU)
When the IM 151/CPU is configured with STEP 7 for operation in the S5 or in
non-Siemens systems, it is clear that only the logical addresses within the slave
CPU are allocated. The addresses are then assigned in the master system using
the specific configuration tool of the master system.
Addressing Interface in STEP 7
The following table illustrates the principles of address allocation. You will also find
this table in the STEP 7 interface. You must set the mode "MS" (for master slave)
or "DX" (direct connection) in STEP 7 (see Section 3.5).
Table 2-4

Addressing Interface in STEP 7 V5.1 (Extract)

Mode Master
I/O
1 MS Q
2 MS Q
3 MS I
4 MS I
MS: Address areas in the
Master IM 151/CPU
slave
2-8
PROFIBUS-DP Partner
Address I/O Address
200 I
300 I
700 Q
50 Q
Address areas in the
DP master CPU
Parameters
Length Unit Consistency
128 4 Byte Unit
132 8 Byte Total length
128 4 Word Unit
136 4 Byte Unit
These address area parameters
must be identical for the DP master
and the IM 151/CPU
ET 200S Interface Module IM 151/CPU
A5E00058783-01