Endress+Hauser RID14, Руководство по эксплуатации

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RID14 Wiring
Hauser 15
A
C
D
B
A0012571
 7 Connection to the PROFIBUS® PA fieldbus cable
A Terminals - fieldbus communication and power supply
B Internal ground terminal
C External ground terminal
D Shielded fieldbus cable
• The terminals for the fieldbus connection (1+ and 2-) are not polarity sensitive.
• Conductor cross-section:
Max. 2.5 mm 2 (14 AWG)
• Always use a shielded cable for the connection.
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 Hauser (see
Section "Accessories").
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