1 function and structure of the racks – Siemens Simatic S7-400 User Manual
Page 72
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
6
7
8
9
10 11 12 13 14 15 16 17 18
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.