Rosemount Model 3144 and 3244MV Smart Temperature Transmitters
2-6
Transmitter Housing
Ground the transmitter housing in accordance with local electrical
requirements. An internal ground terminal is standard. An optional
external ground lug assembly (Option Code G1) can also be ordered if
needed. Ordering certain hazardous approvals automatically includes
an external ground lug (see table on page 5-9). External grounding is
recommended when using the optional transient protector (Option
Code T1).
Surges/Transients
The transmitter will withstand electrical transients of the energy level
usually encountered in static discharges or induced switching.
However, high-energy transients, such as those induced in wiring from
nearby lightning strikes, can damage both the transmitter and the
sensor.
To protect against high-energy transients, install either the integral
transient protection board (Option Code T1) or the Rosemount Model
470 Transient Protector. The integral transient protection board is
available as an ordered option or as an accessory. Refer to “Transient
Protection (Option Code T1)” on page 6-4 for more information. The
Model 470 transient protector is available only as an accessory. Refer to
the Model 470 Transient Protector Product Data Sheet (Rosemount
publication no. 00813-0100-4191) for more information.
Multichannel Installations
You can connect several transmitters to a single master power supply,
as shown in Figure 2-5. In this case, the system may be grounded only
at the negative power supply terminal. In multichannel installations
where several transmitters depend on one power supply, and the loss of
all transmitters would cause operational problems, consider an
uninterruptible power supply or a back-up battery. The diodes shown in
Figure 2-5 prevent unwanted charging or discharging of the back-up
battery.
Figure 2-5. Multichannel Installations.
Transmitter
No. 1
Readout or
Controller No. 1
Transmitter
No. 2
Readout or
Controller No. 2
Battery
Backup
To Additional
Transmitters
dc
Power
Supply
3044
-0
131A
Between 250 and
1100
Ω
If No Load
Resistor
R
Lead
R
Lead
R
Lead