TMT84
Wiring
Hauser
33
The fieldbus system allows three different types of shielding:
• Shielding at both ends.
• Shielding at one end on the feed side with capacitance connection to the field device.
• Shielding at one end on the feed side.
With regard to EMC, the best results are achieved in most cases with one-sided shielding on the
feed side (no capacitance connection to the field device). Operation in the event of disturbance
variables as per NAMUR NE21 is thus guaranteed.
A0008770
Fig. 8: Shielding and one-sided grounding of the fieldbus cable shielding
1
Supply unit
2
Distribution box (T-box)
3
Bus terminator
4
Grounding point for fieldbus cable shielding
5
Optional grounding of the field device, isolated from cable shielding.