Sensor Connections - Emerson Rosemount 848T Reference Manual

Reference Manual
00809-0100-4848
Figure 3-3: Field Communicator Connection Diagram
3.3

Sensor connections

The Rosemount 848T is compatible with a number of RTD and thermocouple sensor types.
Figure 3-4
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.
Emerson.com/Rosemount
shows the correct input connections to the sensor terminals on the transmitter.
Installation
September 2019
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