Endress+Hauser RID14 Bedienungsanleitung Seite 36

Wiring
5.2.2 Fieldbus connector
Optionally, a fieldbus connector can be installed in the field housing instead of a cable gland.
Fieldbus connectors can be ordered as an accessory from Endress+Hauser (see Section
"Accessories" in the Operating Instructions).
The PROFIBUS® PA connection technology allows measuring devices to be connected to the
fieldbus via standardized mechanical connections such as T-boxes, junction box modules etc.
This connection technology using pre-fabricated junction box modules and plug-in connectors
offers considerable advantages over conventional wiring systems:
• Field devices can be removed, replaced or added at any time during normal operation.
Communication is not interrupted.
• Installation and maintenance are considerably easier.
• Existing cable infrastructures can be used and extended immediately, e.g. when creating
new star distributor systems using 4-channel or 8-channel distribution modules.
Shielding the supply line/T-box
Always use cable glands with good EMC properties, where possible with wrapround cable
shielding (Iris spring). This requires minimum differences in potential, and possibly potential
equalization.
• The shielding of the PA cable may not be interrupted.
• The shielding connection must always be kept as short as possible.
Ideally cable glands with Iris springs should be used to connect the shield. The Iris spring,
which is located inside the gland, connects the shield to the T-box housing. The shielding
braid is located under the Iris spring.
When the armored thread is screwed tight, the Iris spring is pressed against the shield,
thereby establishing a conductive connection between the shield and the metal housing.
A junction box or a plug-in connection must be considered part of the shielding (Faraday
shield). This applies in particular to remote boxes if such boxes are connected to a PROFIBUS®
PA device via a plug-in cable. In such cases, you must use a metal connector where the cable
shielding is connected to the connector housing (e.g. pre-terminated cables).
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RID14
Endress+Hauser