Siemens SIMATIC IM 151/CPU

ET 200S in the PROFIBUS Network
3-10
ET 200S Interface Module IM 151/CPU
A5E00058783-01
3.5 Direct Communication
You can configure the IM 151/CPU as an intelligent slave with STEP 7 V 5.1 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 3-6 gives you an example of the relationships you can configure in direct
communication in STEP 7 V 5.1 with an IM 151/CPU. Other DP slaves can only be
senders here.
ET 200S with
IM 151/CPU
(intelligent
slave 2)
S7-300
(DP master system 1)
CPU
31x-2
CPU 31x-2
as DP slave
4
DP slave
3
S7-300
(DP master system 2)
ET 200S with
IM 151/CPU
(intelligent
slave 1)
DP slave
5
PROFIBUS
Figure 3-6 Direct Communication with the IM 151/CPU