Cable Entries; Cable Specifications - Endress+Hauser PROline prowirl 72 PROFIBUS PA Documentation Technique

PROline Prowirl 72/73 PROFIBUS PA
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Endress+Hauser
Service adapter
The service adapter is exclusively for connection to E+H approved service interfaces.
Warning!
It is not permissible to connect the service adapter in explosive atmospheres.

Cable entries

Choice of thread for cable entries, M20x1.5 or ½" NPT or G ½" thread (see also the
figures on Page 2 and Page 3, number

Cable specifications

The sensor cable connection between sensor and transmitter has an EEx i type of
protection rating (see also the figure on Page 3; number
The max. capacitance of the cable is 1 µ F/km.
The max. cable inductivity is 1 mH/km.
The cable delivered by E+H (max. 30 m) fulfils these requirements.
Fieldbus connector
The connection technology of PROFIBUS PA allows measuring devices to be connec-
ted to the fieldbus via uniform mechanical connections such as T-boxes, junction
boxes, etc. This connection technology using prefabricated distribution modules and
plug-in connectors offers substantial advantages over conventional wiring:
• Field devices can be removed, replaced or added at any time during normal
operation. The communications will not be interrupted.
• This simplifies installation and maintenance significantly.
• Existing cable infrastructures can be used and expanded instantly, e.g. when
constructing new star distributors using 4-channel or 8-channel junction boxes.
The Prowirl 72 PROFIBUS PA resp. Prowirl 73 PROFIBUS PA can therefore be supplied
with a ready-mounted fieldbus connector. Fieldbus connectors for retrofitting can be
ordered from E+H as a spare
Supply line/T-box shielding
Use cable glands with good EMC properties, if possible with all-round contact of
the cable shielding (Iris spring). This requires small differences in potential, poss.
potential equalisation.
• The PA cable shielding must be intact.
• The shielding connection must always be kept as short as possible.
Ideally, cable glands with Iris springs should be used for the shielding connection.
The shielding is positioned on the T-box housing by means of the Iris spring located
inside the gland. The shielding braid is located beneath the Iris spring. When the
armoured thread is tightened, the Iris spring is pressed against the shielding, thereby
creating a conductive connection between the shielding and the metal housing.
A connection box or a plug-in connection is to be seen as part of the screening
(Faraday shield). This applies, in particular, to remote boxes if these are connected to
a PROFIBUS PA measuring device by means of a pluggable cable. In such instances,
a metallic connector must be used where the cable shielding is positioned at the plug
housing (e.g. prefabricated cables).
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