GB
11258421.0901/2012GB/D
34 WIKAoperatinginstructionstemperaturetransmitterT32.xS
Shouldthecoldjunctioncompensationbeoperatedwith
anexternalresistancethermometer(2-wireconnection),
connectthistoterminalsand.
9.3.4 Connect mV sensor
MakesurethatthemVsensorisconnectedwiththecorrectpolarity.
9.3.5 Potentiometer
Connectionofapotentiometerispossible.
9.4 HART
®
signal
TheHART
®
signalismeasureddirectlyviathe4...20mAsignalline.
Themeasuringcircuitmusthavealoadofatleast250Ω.However,
theloadmustnotbetoohigh,asotherwise,inthecaseofrelatively
highcurrents,theterminalvoltageatthetransmitterwillbetoolow.
Forthatreason,connectthecableclampsofthemodemand/or
theHART
®
communicator,asdescribed(seechapter6.5"HART
®
congurationtree"orusetheexistingcommunicationconnectorsofa
powersupply/linetransformer.TheconnectionoftheHART
®
modem
and/ortheHART
®
communicatorisnotdependantonpolarity!The
HART
®
modemortheHART
®
communicatormayalsobeconnected
paralleltotheresistor!WhenconnectinganExversionofthetrans-
mitter,observethespecialconditionsforsafeuse(seechapter10
"Notesformountingandoperatinginhazardousareas").
9. Electrical connections