Fig. 4-26: Shielded Signal Cable, Shield Connected At One End; Fig. 4-27: Double-Shielded Signal Cable, Shields Connected At Both Sides - Emerson Rosemount Xstream Series Instruction Manual

X-STREAM
Local on-site conditions usually differ from test
conditions and may require special measures.
This is when strong fields are expected,
potentially generating high parasitic currents
on the cable shield . Such currents result in
differences of potential between connected
housings.
Two possible measures to avoid parasitic
currents are described, whereat installation
personnel familiar with EMC problems has to
decide about the use of either measure:
• Using double-shielded cables:
In this case one shield is connected to the
analyzer's housing while the other shield
is connected to the external equipment.
This gives an advantage when both
instruments are supplied by different
supply networks (e.g. when installed in dif-
ferent buildings).
4-30
4-5 Installation - Hints on Wiring
Fig. 4-26: Shielded Signal Cable,
shield connected at one end
Fig. 4-27: Double-shielded Signal Cable,
shields connected at both sides
Shield is connected at one side of the
•
cable only (recommended to the analyzer's
housing): Protection against external
distrubances is increased but influence by
parasitic currents is prevented due to
opening the ground loop.
This measure is more costlybut offers best
immunity against distrubances from outer
fields and from parasitic currents.
Emerson Process Management GmbH & Co. OHG
Instruction Manual
HASAxE-IM-HS
07/2006