Siemens M7-400, S7-400 2.1 Function and Structure of the Racks

Racks
2-2 S7-400, M7-400 Programmable Controllers Module Specifications
A5E00069467-07
2.1 Function and Structure of the Racks
Introduction
The racks in the S7-400 have the following tasks:
•They hold the modules
•They supply the modules with operating voltage
•They connect the individual modules to each other via the signal buses
Structure of the Racks
A rack consists of the following elements:
•Mounting rail with threaded bolts for fixing the modules and lateral cutouts for
mounting the rack
•Plastic parts that function, among other things, as guides when swinging the
modules into place.
•A backplane bus, an I/O bus and, if necessary, a communication bus with bus
connector
•Connection for local ground
Figure 2-1 shows the mechanical configuration of a rack (UR1).
Aluminum carrier Plastic parts
Connection for local ground Bus connector (covered when shipped)
1 2 3 4 5 67 8 9101112131415161718
Figure 2-1 Structure of a Rack with 18 Slots
UL/CSA Note
Special requirements should be taken into consideration in the area of influence of
the UL/CSA; these may be fulfilled by installing the system in a cabinet.