Siemens SIMATIC S7-400 Configuration And Use Manual page 86

Configuration Variants of the S7-400
Advantages
Wiring the S7-400 with front connectors offers you the following advantages:
• Front connectors allow you to use pre-assembled cables.
• You save time and money during assembly.
• The capability to pull and plug a completely wired front connector makes
exchanging modules fast and easy.
• It makes it difficult to accidentally insert the front connectors in the wrong
direction, since they have mechanical polarization; front connectors and
modules are assigned to one another.
Fully Modular Connection
Signals can not only be connected directly to the signal modules, they can also be
connected to a remote terminal. The terminal is connected to a front connector
module that is plugged into the signal module instead of the front connector. The
distance between the terminal and signal module can reach up to 30 m.
Advantages
Wiring with a fully modular connection offers the following advantages:
• Fast, low-cost wiring
• High degree of wiring safety, orderly cabinet wiring
• The supply voltage for the module can be connected to the front connector
module or to the terminal block.
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Automation System S7-400 Configuration and Use
A5E00442711-02