Emerson Rosemount 3051 CF Series, Reference Manual

Page: 89 / 146

the drip loop so the bottom is lower than the conduit connections and the
transmitter housing.
4.6.2 Grounding the transmitter
Signal cable shield grounding
Signal cable shield grounding is summarized in Figure 4-3 and Figure 4-5 . The signal cable
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 and Figure 4-5 for instructions on grounding the transmitter case. Follow the
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
Transmitter wiring .
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.
3. Continuously connect the cable shields to the power supply ground.
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.
4. Replace the housing cover.
Emerson recommends tightening the cover until there is no gap between the cover
and the housing.
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 Electrical installation
00809-0100-4774 July 2020
Reference Manual 89