Emerson Rosemount 2051G, Справочное руководство

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42
Reference Manual
00809-0400-4101, Rev BA
Electrical Installations
January 2018
Electrical Installations
2. For 4–20 mA HART output, connect the positive lead to the terminal marked (pwr/comm+) and the
negative lead to the terminal marked (pwr/comm–). Do not connect the powered signal wiring to the
test terminals. Power could damage the test diode.
3. Ensure full contact with Terminal Block screw and washer. When using a direct wiring method, wrap
wire clockwise to ensure it is in place when tightening the terminal block screw.
Note
The use of a pin or ferrule wire terminal is not recommended as the connection may be more susceptible
to loosening over time or under vibration.
4. Plug and seal unused conduit connection on the transmitter housing to avoid moisture accumulation
in the terminal side.
4.6.4 Grounding the transmitter
Signal cable shield grounding
Signal cable shield grounding is summarized in Figure 4-7 on page 42 . 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
“Transmitter case grounding” on page 43 for
instructions on grounding the transmitter case. Follow the steps below to correctly ground the signal
cable shield.
1. Remove the field terminals housing cover.
2. Connect the signal wire pair at the field terminals as indicated in Figure 4-6 .
3. At the field terminals, the cable shield and shield drain wire should be trimmed close and insulated
from transmitter housing.
4. Reattach the field terminals housing cover; cover must be fully engaged to comply with explosion
proof requirements.
5. At terminations outside the transmitter housing, the cable shield drain wire should be continuously
connected.
a. Prior to the termination point, any exposed shield drain wire should be insulated as shown in
Figure 4-7 (B).
6. Properly terminate the signal cable shield drain wire to an earth ground at or near the power supply.
Figure 4-7. Wiring Pair and Ground
A. Insulate shield and shield drain wire
B. Insulate exposed shield drain wire
C. Terminate cable shield drain wire to earth ground
DP
A
B
C