Installing the S7-400
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AutomationSystem S7-400 Hardwareand Installation
A5E00850741-01
2.14 Marking the Modules with Slot Labels

Slot Number

Once the modules are installed, you should mark each one with its slot number to
avoid the risk of mixing up modules during operation. If modules do get mixed up,
you may have to reconfigure the assembly.
The slot number is printed on the rack.
Double-width modules occupy two slots and are assigned the consecutive slot
numbers of both slots.
Triple-widthmodules occupy three slots and are assigned the c onsecutive slot
numbers of these three slots.

Fitting Slot Labels

Youuse slot labels to mark a module with its slot number. The slot labels are
provided with the rack as a “number wheel”.
Toattach the slot labels:
1. Holdthe “number dial” on the module and rotate it to the slot number for the
module inserted at this slot.
2. Useyour finger to press the slot label into the module. The label will break away
from the “number wheel”.
Figure 2-6 Fitting a Slot Label