Siemens S5-135U/155U - Manual (Page 21)

2-3
System Manual
C79000-G8576-C199-06
2.2 Centralized and Distributed Configuration
You can install a PLC in centralized or distributed configuration according to
your application.
IF ... THEN ...
you wish to position the modules as closely as
possible to the CC and can accept longer cable runs to
the process, choose the
centralized
configuration
you wish to position the I/O modules as closely as
possible to the process and can accept longer cable
runs to the CC, choose the
distributed
configuration
With the centralized configuration, you can install the CC and EUs in the
same cabinet or in adjacent cabinets. Data transmission is parallel. Shown in
the following figure is a centralized configuration.
EU
EU
CC
Load Power Supply
Figure 2-1 Centralized Configuration
Centralized and Distributed Configuration of a Programmable Controller