Vega VEGAPULS 11 - Page 18

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5 Connecting to power supply
VEGAPULS 11 • Two-wire 4 … 20 mA
58350-EN-200806
5 Connecting to power supply
5.1 Preparing the connection
Always keep in mind the following safety instructions:
•
Carryoutelectricalconnectionbytrained,qualiedpersonnel
authorised by the plant operator
Warning:
Only connect or disconnect in de-energized state.
Thedataforpowersupplyarespeciedinchapter"Technical data".
Note:
Power the instrument via an energy-limited circuit (power max. 100 W)
acc. to IEC 61010-1, e.g.
•
Class 2 power supply unit (acc. to UL1310)
•
SELV power supply unit (safety extra-low voltage) with suitable
internal or external limitation of the output current
Keepinmindthefollowingadditionalfactorsthatinuencetheoperat-
ing voltage:
•
Lower output voltage of the power supply unit under nominal load
(e.g. with a sensor current of 20.5 mA or 22 mA in case of fault)
•
Inuenceofadditionalinstrumentsinthecircuit(seeloadvaluesin
chapter " Technical data")
Use cable with round cross section for instruments with housing and
cablegland.Toensurethesealeectofthecablegland(IPprotection
rating),ndoutwhichcableouterdiameterthecableglandissuitable
for.
The instrument is connected with standard two-wire cable.
If electromagnetic interference is expected which is above the test
values of EN 61326-1 for industrial areas, shielded cable should be
used.
Note:
If the temperatures are too high, the cable insulation can be dam-
aged. Hence keep apart from the ambient temperature also the self-
heating of the instrument for the temperature resistance of the cable
in the connection compartment in mind
2)
.
We recommend to connect the cable screening to ground potential at
one end on the supply side when using shielded cable.
Metric threads
In the case of instrument housings with metric thread, the cable gland
is screwed in at the factory. It is sealed with plastic plugs as transport
protection.
Safety instructions
Voltage supply
Connection cable
Cable screening and
grounding
Cable gland
2)
 Withanambienttemperature≥50°C(122°F)theconnectioncableshould
besuitableforatemperaturewhichisatleast20°C(36°F)higher.