KROHNE MFC 300 FOUNDATION FIELDBUS EN - Manual (Page 6)

3
ELECTRICAL CONNECTIONS
6
MFC 300
www.krohne.com 02/2013 - 4001086702 - AD MFC 300 FF R02 en
All bus segments must be fitted with a terminator at both ends.
3.4 Shielding and grounding
• For optimum electromagnetic compatibility of systems it is extremely important that the
system components, and particularly the bus cables connecting the components, are
shielded and that such shields - if possible - form an unbroken cover.
• Hence, it follows that, for use in non-hazardous duty systems, the cable shield should be
grounded as often as possible.
• In Ex systems an adequate equipotential bonding in the hazardous and non-hazardous
location along the entire Fieldbus installation is strongly recommended. Multiple grounding
of the shield is of advantage.
• In explosion-proof systems the shielding must at least be connected at one end of the cable.
• NAMUR NE 21 compliance is given, provided the above recommended cable types are used.
Number of devices Cable lengths for number of devices per branch line
1 device 2 devices 3 devices 4 devices
25...32 1 m / 3.3 ft 1 m / 3.3 ft 1 m / 3.3 ft 1 m / 3.3 ft
19...24 30 m / 100 ft 1 m / 3.3 ft 1 m / 3.3 ft 1 m / 3.3 ft
15...18 60 m / 200 ft 30 m / 100 ft 1 m / 3.3 ft 1 m / 3.3 ft
13...14 90 m / 300 ft 60 m / 200 ft 30 m / 100 ft 1 m / 3.3 ft
1..12 120 m / 400 ft 90 m / 300 ft 60 m / 200 ft 30 m / 100 ft
INFORMATION!
The use of twisted and shielded cables is strongly recommended, otherwise EMC protection of
the signal converter cannot be assured.