Reference Manual
00809-0100-4697, Rev EA
October 2011
Rosemount 848T
2-4
WIRING If the sensor is inst alled in a high-volt age en vironment and a fault cond ition or
installation error occu rs, the sens or lead s an d tra ns m itte r te rm in als co uld
carry lethal volta ges. Use extreme caution when making contact with the
leads and terminals.
NOTE
Do not apply high voltage (e.g. AC line voltage) to the transmitter terminals.
Abnormally high voltage can dama ge the unit (bus terminal s are rate d to 4 2.4
VDC).
Figure 2-3. 848T Transmitter
Field Wiring
Connections The 848T transmitter is compatible with 2 or 3-wir e RTD, thermocoup le, Ohm,
and millivolt sensor types. Figure 2-4 shows the correct input connections to
the sensor terminals on the transmitter. The 848T can also accept inputs from
analog devices using the optional analog input connector. Figure 2-5 shows
the correct input connectio ns to the analog input connector when inst alled on
the transmitte r. Tighten the termina l sc re ws to ens ure pr op er c onne ction.
Figure 2-4. Sensor Wiring
Diagram
* Intrinsically safe installations may allow fewer devices per I.S. barrier
Power
Supply
Terminators
Devices 1 through 16*
Integrated Power
Conditioner
and Filter
(Spur)
(Spur)
Signal
Wiring
FOUNDATION
fieldbus Host or
configuration tool
6234 ft (1900 m) max
(depending upon cable
characteristics)
(Trunk)
* Emerson Process Management provides 4-wire sensors for all single-element RTDs. Use these
RTDs in 3-wire configurations by clipping the fourth lead or leavi ng it disconnected and insulated
with electrical tape.
** The transmitter must be configured for a 3-wire RTD in order to recognize an RTD with a
compensation loop.
123
2-wire
RTD and
Ohms
3-wire
RTD and
Ohms*
Thermocouples /
Ohms and
Millivolts
123 123 2-Wire RTD
with
Compensation
Loop**
123