Rosemount 848T, Справочное руководство

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Reference Manual
00809-0100-4848, Rev AA
July 2009
3-3
Rosemount 848T Wireless
375 Field Communicator Connections
The Power Module needs to be connected for the 375 Field Communicator to
interface with the 848T Wireless.
Figure 3-3. Field Communicator
Connection Diagram
SENSOR CONNECTIONS
The 848T Wireless is compatible with a number of RTD and thermocouple
sensor types. Figure 3-4 on page 3-4 shows the correct input connections to
the sensor terminals on the transmitter. To ensure a proper sensor
connection, anchor the sensor lead wires into the appropriate compression
terminals and tighten the screws.
Thermocouple or Millivolt Inputs
Use appropriate thermocouple extension wire to remote mount the transmitter
from the sensor. Make millivolt input connections with copper wire. Use
shielding for long runs of wire.
RTD or Ohm Inputs
There are various RTD configurations, including the 2-, 3-, and 4-wire, used in
industrial applications. A 3- or 4-wire RTD operates within specification,
without recalibration, for lead wire resistances up to 60 ohms per lead. This is
the equivalent of 6,000 ft of 20 AWG wire. For a 2-wire RTD, both RTD leads
are in series with the sensor element, so an error can occur in lead lengths
that exceed one foot of 20 AWG wire. This error can be eliminated by using a
3- or 4-wire RTD.
Maintenance Port