Emerson Rosemount 3490 Series Reference Manual page 29

Reference Manual
00809-0100-4841
It is the responsibility of the user to ensure that any transmitter is installed in accordance
with the manufacturer's instructions supplied with the transmitter.
Cable between the control unit and the transmitter should be shielded twisted-pair with
the shield connected to terminal 3 (marked with earth symbol) on the control unit.
The shield should be left unconnected at the transmitter unless there is a terminal
specifically provided for this purpose.
Cable runs should be separate from any high voltage or mains cables to avoid crosstalk or
interference. Multi-core cable may be used if the other cores carry only low voltage (24
Vdc nominal) signals and each pair of cores is individually screened (shielded).
Loop-powered transmitters must be connected to terminals 1, 2, and 3 on the control unit
(see Figure
Figure 3-7: Loop-powered Transmitter Connections
24 V
I
IN
A. Control unit
B. Transmitter
The control unit supplies 23 Vdc from a 400 Ohm source to power transmitters. Separately
powered transmitters must be connected to terminals 2 and 3 (see
Figure 3-8: Self-powered Transmitter Connections
24 V
I
IN
A. Control unit
B. Transmitter
Emerson.com/Rosemount
3-7).
A B
1
2
3
A
1
B
2
3
Installation
January 2021
Figure 3-8).
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