Emerson Rosemount 3051S MultiVariable - Page 88

Grounding to ground the transmitter case. Do not run transient protection ground wire
with signal wiring; the ground wire may carry excessive current if a lightning strike occurs.
Signal wire grounding
Do not run signal wiring in conduit or open trays with power wiring, or near heavy
electrical equipment. Ground the shield of the signal wiring at any one point on the signal
loop. See Figure 3-13. The negative terminal of the power supply is a recommended
grounding point.
Figure 3-13: Signal Wire Grounding
DP
A
E
B
C
D
F
A. Positive
B. Negative
C. Connect shield back to the power supply negative terminal
D. Insulate shield
E. Minimize distance
F. Trim shield and insulate
Power supply 4–20 mA transmitters
The DC power supply should provide power with less than two percent ripple. Total
resistance load is the sum of resistance from signal leads and the load resistance of the
controller, indicator, and related pieces. Note that the resistance of intrinsic safety
barriers, if used, must be included.
See for transmitter resistance load limits.
Note
A minimum loop resistance of 250 ohms is required to communicate with a Field
Communicator. If a single power supply is used to power more than one Rosemount
3051SMV, the power supply used and circuitry common to the transmitters should not
have more than 20 ohms of impedance at 1200 Hz.
3.4.7
Conduit electrical connector wiring (option GE or GM)
For Rosemount 3051SMV with conduit electrical connectors GE or GM, refer to the cordset
manufacturer’s installation instructions for wiring details. For FM Intrinsically Safe, non-
Installation
Reference Manual
October 2018 00809-0100-4803
88 Rosemount 3051S Multivariable Transmitter