Direct Communication; Direct Communication With The Im 151-7 Cpu - Siemens SIMATIC ET 200S Manual

ET 200S in the PROFIBUS Network
4.5

Direct communication

You can configure the IM 151-7 CPU as an intelligent slave with STEP 7 V5.1 for
direct communication. Direct communication is a special communication
relationship between PROFIBUS-DP nodes.
Principle
Direct communication is characterized by the fact that the PROFIBUS-DP nodes
"listen in" to find out which data a DP slave is sending back to its DP master. Using
this function, the eavesdropper (recipient) can directly access changes to the input
data of remote DP slaves.
During configuration in STEP 7, you set via the relevant I/O input addresses the
address area of the recipient at which the required data of the sender is to be read.
Example
Figure 4-7 gives you an example of the relationships you can configure for direct
communication in STEP 7 with an IM 151-7 CPU. Other DP slaves can only be
senders here.
CPU
31x-2
ET 200S with
IM 151-7 CPU
(intelligent
slave 1)
Figure 4-7

Direct communication with the IM 151-7 CPU

4-12
S7-300
(DP master system 1)
ET 200S with
IM 151-7 CPU
(intelligent
slave 2)
S7-300
(DP master system 2)
DP slave CPU 31x-2
3 as DP slave
4
ET 200S IM 151-7 CPU Interface Module
PROFIBUS
DP slave
5
A5E00058783-04