Siemens SIMATIC S7-300 Hardware And Installation Manual page 46

Configuring
5.8.3 Installing an S7-300 with ungrounded reference potential (not CPU
312 IFM or CPU 31xC)
Introduction
If you install an S7-300 with ungrounded reference potential, any interference
currents that occur are dissipated via an RC system to the ground conductor/local
ground integrated into the CPU.
Note
Floating potential installation of an S7-300 with CPU 312 IFM or CPU 31xC is not
possible.
Application
In larger plants, it might prove necessary to install the S7-300 with floating
reference potential because of short-circuit to ground monitoring. This is the case,
for example, in chemical industry and power stations.
Floating reference potential on CPUs 313 – 318-2 DP
This connection diagram applies to the
CPU
CPU 313
CPU 314
CPU 314 IFM
CPU 314 IFM
CPU 315
CPU 315-2 DP
CPU 316-2 DP
CPU 318-2 DP
The diagram illustrats an S7-300 configuration with floating reference potential
(implemented with a jumper).
5-20
Order No.
6ES7 313-1AD03-0AB0
6ES7 314-1AE04-0AB0
6ES7 314-1AE84-0AB0
6ES7 314-5AE03-0AB0
6ES7 314-5AE83-0AB0
6ES7 315-1AF03-0AB0
6ES7 315-2AF03-0AB0
6ES7 315-2AF83-0AB0
6ES7 316-2AG00-0AB0
6ES7 318-2AJ00-0AB0
S7-300 Programmable Controller Hardware and Installation
From hardware
version
01
01
01
01
01
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03
A5E00105492-02