Siemens SIMATIC PN/M-Bus LINK Operating Instructions Manual page 32

Connecting
7.2 Power supply and potential ratios
Shielding
PROFINET interface
The shields of the PROFINET interface are galvanically connected.
Always apply the shields of the PROFINET Ethernet cable at both ends.
M-Bus interface
You can use either shielded or unshielded M-Bus cables in the M-Bus network. However, we
do recommend the use of shielded M-Bus cables.
In accordance with the standard, the M-Bus cable shield should only be connected on the
side of the M-Bus master.
The M-Bus cable shield can alternatively be connected as follows:
● To a shield busbar (FE)
● To the M-Bus screw-type terminal. With this type of connection, there is capacitive
grounding of the cable shield.
NOTICE
Adequate immunity to interference can only be achieved by attaching the shields of the
PROFINET cables and M-Bus cables to a shield busbar in accordance with EMC
requirements.
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Operating Instructions, 03/2018, A5E44260928-AA
PN/M-Bus LINK