Vega MINITRAC 31 - Page 22

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5Connectingtopowersupply
MINITRAC 31 • Foundation Fieldbus
41782-EN-211203
NPT thread
Inthecaseofinstrumenthousingswithself-sealingNPTthreads,itis
notpossibletohavethecableentriesscrewedinatthefactory.The
freeopeningsforthecableglandsarethereforecoveredwithreddust
protection caps as transport protection.
Beforesetupyouhavetoreplacetheseprotectivecapswithapproved
cableglandsorclosetheopeningswithsuitableblindplugs.Unused
cableglandsdonotprovidesucientprotectionagainstmoistureand
mustbereplacedwithblindplugs.
Thesuitablecableglandsandblindplugscomewiththeinstrument.
Make sure that the cable screen and grounding are carried out ac-
cordingtoFieldbusspecication.Werecommendtoconnectthe
cable screening to ground potential on both ends.
Insystemswithpotentialequalisation,connectthecablescreening
directlytogroundpotentialatthepowersupplyunit,intheconnection
box and at the sensor. The screen in the sensor must be connected
directly to the internal ground terminal. The ground terminal outside
onthehousingmustbeconnectedtothepotentialequalisation(low
impedance).
The voltage supply and signal output are connected via the spring-
loaded terminals in the housing.
Connection to the display and adjustment module or to the interface
adapter is carried out via contact pins in the housing.
Proceedasfollows:
Theprocedureappliestoinstrumentswithoutexplosionprotection.
1. Unscrewthebighousingcover
2. Loosen compression nut of the cable gland and remove blind
plug
3. Removeapprox.10cm(4in)ofthecablemantle,stripapprox.
1cm(0.4in)ofinsulationfromtheendsoftheindividualwires
4. Insert the cable into the sensor through the cable entry
Cable screening and
grounding
Connection technology
Connection procedure