Siemens S5-135U/155U appendix Application

Centralized and Distributed Configuration of a Programmable Controller

2.1Application

The S5-135U/155U programmable controllers comprise a central controller

(CC)and, if required, one or more expansion units (EUs). You need EUs when there are insufficient slots in the CC for the modules to be used.

Various interface modules (IMs) are available for communication between the CC and the EUs and between the EUs. It is therefore possible to install an EU or EUs in the immediate vicinity of the CC (centralized configuration) or at some distance (distributed configuration). A combination of both types of configuration is also possible by connecting additional EUs in a centralized configuration with a distributed EU (see Figure 2-5).

This is clarified on the following pages.

2-2	System Manual
	C79000-G8576-C199-06