Emerson 3051SMV Reference Manual page 34

Installation
January 2017
4. Trim the cable shield as short as practical and insulate from touching the transmitter housing as
indicated in
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. To protect the fieldbus segment from
noise, grounding techniques for shield wire require a single grounding point for shield wire to avoid
creating a ground loop.
The cable shield should maintain a continuous connection to the power supply ground.

Connect cable shields for entire segment to a single good earth ground at power supply.

Improper grounding is the most frequent cause of poor segment communications.

5. Reinstall the housing cover and tighten so the cover is fully seated with metal to metal contact
between the housing and cover in order to meet explosion proof requirements.
6. Plug and seal unused conduit connections.
NOTICE
When the enclosed threaded plug is utilized in the conduit opening, it must be installed with a
minimum thread engagement in order to comply with explosion-proof requirements. For straight
threads, a minimum of seven threads must be engaged. For tapered threads, a minimum of five threads
must be engaged.
Figure 3-9. Wiring Terminals with RTD
A. Protective grounding terminal
(do not ground cable shield at the transmitter)
B. Trim shield and insulate
26
Figure 3-9 and Figure 3-10.
A
C
B
P D
C. Minimize distance
D. Insulate shield
E. Connect shield back to the power supply ground
Reference Manual
00809-0100-4853, Rev AB
C
D
E
Installation