Potential Ratios - Siemens Simatic Operating Instructions Manual

7.2

Potential ratios

Electrical isolation
Electrical isolation for the PN/CAN LINK exists between the following switching components:
● The signals of the PROFINET interfaces are galvanically isolated from each other, from
the electronics or 24 V supply voltage and from the fieldbus interfaces.
● The CAN interface is galvanically isolated from the power supply.
Shielding
The shields of the PROFINET interface are galvanically connected.
NOTICE
Sufficient interference immunity is only achieved through EMC compliant application of the
cable shields of the PROFINET cables to a shield rail.
The shields of the CAN interface are capacitively decoupled from the shields of the
PROFINET interface to prevent compensating currents over the cable shields.
Figure 7-1
SIMATIC PN/CAN LINK
Operating Instructions, 03/2018, A5E39895388-AB
Block diagram shielding
Connecting
7.2 Potential ratios
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