Emerson Rosemount 3051CF Series Reference Manual page 89

Reference Manual
00809-0100-4774
4.6.2 Grounding the transmitter
Signal cable shield grounding
Signal cable shield grounding is summarized in
shield and unused shield drain wire must be trimmed and insulated, ensuring that the
signal cable shield and drain wire do not come in contact with the transmitter case. See
Figure 4-4
steps below to correctly ground the signal cable shield.
Do not run signal wiring in conduit or open trays with power wiring, or near heavy
electrical equipment. Grounding terminations are provided on the outside of the
electronics housing and inside the terminal compartment. Use these grounds when
transient protect terminal blocks are installed or to fulfill local regulations.
Procedure
1. Remove the field terminals housing cover.
2. Connect the wiring pair and ground as indicated in
3. Continuously connect the cable shields to the power supply ground.
4. Replace the housing cover.
5. Plug and seal unused conduit connections.
Transmitter case grounding
Always ground the transmitter case in accordance with national and local electrical codes.
The most effective transmitter case grounding method is a direct connection to earth
ground with minimal impedance. Methods for grounding the transmitter case include:
• Internal ground connection: The internal ground connection screw is inside the FIELD
TERMINALS side of the electronics housing. This screw is identified by a ground symbol
Reference Manual
the drip loop so the bottom is lower than the conduit connections and the
transmitter housing.
and Figure 4-5 for instructions on grounding the transmitter case. Follow the
a) Trim the cable shield as short as practical and insulate from touching the
transmitter housing.
Note
Do NOT ground the cable shield at the transmitter; if the cable shield touches
the transmitter housing, it can create ground loops and interfere with
communications.
a) Connect the cable shields for the entire segment to a single good earth
ground at the power supply.
Note
Improper grounding is the most frequent cause of poor segment
communications.
Emerson recommends tightening the cover until there is no gap between the cover
and the housing.
Electrical installation
Figure 4-3 and Figure 4-5. The signal cable
Transmitter wiring.
July 2020
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