Wiring the S7-400
4-35
AutomationSystem S7-400 Hardwareand Installation
A5E00850741-01
4.20 Interconnecting the CR and ER(s)

Interconnecting the Interface Modules

When you assemble an automation system comprising a CR and one or moreERs,
you connect the racks via the connecting cables of the interface modules.
Tointerconnect the interface modules:
1. Ensurethat all the connecting cables needed for the programmable controller
are ready.Allow for the maximum cable lengths permitted for your assembly
(see Chapter 2) and check that you have the correct cables
(see Reference Manual Module Specifications, Chapter 6).
2. Startwith the send IM (the interface module in the central rack).
3. Openthe cover of the send IM.
4. Plugthe male connector of the first connecting cable into one of the female
connectors of the send IM and screw-tighten it.
Figure 4-22 Plugging a Connecting Cable into a Send IM
5. Ifyou wish to interconnect two ERs segments to this send IM, plug the
connector of the second connecting cable into the second port of the send IM.
6. Closethe cover of the send IM.