A0017830
11 Inserting the cable, field housing
Inserting the cable, field housing, connection without transmitter power supply (example)
1. Release the housing screws
2. Open the housing
3. Open the cable gland (M16) and insert the cable
4. Connect the cable incl. functional grounding and close the cable gland
6.6 Shielding and grounding
Optimum electromagnetic compatibility (EMC) can only be guaranteed if the system
components and, in particular, the lines are shielded and the shield forms as complete a
cover as possible. A shield coverage of 90% is ideal.
• To ensure an optimum EMC protective effect when communicating with HART
®
, connect
the shield as often as possible to the reference ground.
• For reasons of explosion protection, you should refrain from grounding however.
To comply with both requirements, three different types of shielding are possible when
communicating with HART
®
:
• Shielding at both ends
• Shielding at one end on the feed side with capacitance termination at the field device
• Shielding at one end on the feed side
Experience shows that the best results with regard to EMC are achieved in most cases in
installations with one-sided shielding on the feed side (without capacitance termination at
the field device). Appropriate measures with regard to input wiring must be taken to allow
unrestricted operation when EMC interference is present. These measures have been
taken into account for this device. Operation in the event of disturbance variables as per
NAMUR NE21 is thus guaranteed. Where applicable, national installation regulations and
guidelines must be observed during the installation! Where there are large differences in
potential between the individual grounding points, only one point of the shielding is
connected directly with the reference ground. In systems without potential equalization,
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