D-2Problem PossibleCause PossibleSolution
No
communication
withfield device
Insufficientloop resistance
atthe HART frequenci es. Addan additiona l 250 ohm
resistorin series inthe loop.
Placethe HART Communic ator
leadsacross the re sistor and
verifyif communication has
beenrestored.
Insufficientloop current and
voltageat the field device
terminals.
Verifythat there is at least 4mA
and12V DC at the field device
terminals.
Fielddevice may be set to
HARTaddress other t han
zero(multi-drop mode).
Change275 mode to digital
polling.
Controlsystem is
communicating
HART,but the
275isnot
communicating
properly
HARTcommunication with
theHART Communicator is
beingprevented by the
controlsystem
StopHART communications on
thecontrol system and verify if
communicationbetween the
fielddevices and HART
Communicatoris restored.
Batterypack
doesnotaccepta
charge
Batterypack has been
dischargedpast the no rmal
range.
Removebattery pack and
rechargewhile it is
disconnectedfrom the
Communicator.
+24VDC
Power
250ohm resistor
24VDC
Return
Field
Device
ControlSystem field
Terminalblocks
0.1uFto
0.22uF
External
Capacitor
Shieldterminal.
Floatingat
transmitterend
250ohm
external
loopresistor
Control
SystemSide Field
Deviceside
Fielddevicemust
have4mA and 12V
DCat terminals
Explosionscan res ultin de ath or
seriousinjury. Do not exceed the
allowedloop capacitanc e.
WARNING
!