Wiring the S7-400
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AutomationSystem S7-400 Hardwareand Installation
A5E00850741-01
Filtering the 24 VDC Supply
When you power the S7-400 from a battery with the ungrounded configuration, you
must provide interference suppression for the 24 VDC supply.Use a Siemens
power cable filter,such as the B84102-K40.
Insulation Monitoring
If a double fault could cause a hazardous state in the installation, you must provide
insulation monitoring.
Example of Ungrounded Operation
If you have configured an S7-400 with a local connection and you only wish to
ground the overall installation at the CR, you can operate the ERs in an
ungrounded configuration.
Note
If you connect an ER via a local connection with 5 V transfer,ungrounded
operation is mandatory for the ER.