Emerson 3081FG - Manual (Page 28)

Instruction Manual
IB-106-3081 Rev. 1.5
September 2002
2-10 Installation Rosemount Analytical Inc. A Division of Emerson Process Management
Model 3081FG
pairs are recommended. Ground the trans-
mitter housing to an earth ground to prevent
unwanted electromagnetic interference
(EMI) or radio frequency interference (RFI).
NOTE
For optimum EMI/RFI immunity, shield
the 4-20 mA current loop cable and
enclose in an earth grounded metal
conduit.
NOTE
Never run signal or sensor wiring in
the same conduit, or open tray, with
power cables. Keep signal or sensor
wiring at least 12 in. (0.3 m) away from
other electrical equipment and 6.5 ft (2
m) from heavy electrical equipment.
It is necessary to prevent moisture from
entering the Model 3081 Transmitter hous-
ing. The use of weather-tight cable glands is
required. If conduit is used, plug and seal
connections on the transmitter housing to
prevent moisture accumulation in the termi-
nal side of the housing.
Moisture accumulation in the transmit-
ter housing can affect its performance
and may void its warranty.
b. Oxygen Probe Signal Connections
1. Two signals represent the O
2
value and
the cell temperature. The probe pro-
vides these values to the Model 3081
Transmitter for processing and signal
conditioning.
2. Wiring connections for the probe are
shown in Figure 2-9.
c. Model 3081 Transmitter 4-20 mA and
Signal Connections
1. A 4-20 mA signal represents the O
2
value. Superimposed on the 4-20 mA
signal is HART information that is ac-
cessible through a Model 275 Hand-
held Communicator or AMS software.
2. Two signals representing the O
2
value
and the cell temperature are supplied
to the Model 3081 Transmitter from the
oxygen probe.
3. Wiring connections for the Model 3081
Transmitter are shown in Figure 2-10.
NOTE
The ground arrangement shown in
Figure 2-10 limits the amount of noise
introduced into the electronics.
4. Connect wire shields to terminal 1.
Connect earth ground as shown.
THERMOCOUPLE
+
(GY)
THERMOCOUPLE
-(RD)
TERMINAL
BLOCK
CONDUIT
CELL
-(WH)
CELL
+
(BK)
26020004
Figure 2-9. Oxygen Probe Terminal Block