
35
Reference Manual
00809-0100-4808, Rev DA
Installation
October 2016
Installation
Figure 3-7. Power Supply Load Limitations
3.5.2
Wiring
To make connections, perform the following procedure.
1. Remove the housing cover on the side marked “FIELD TERMINALS.” Do not remove the cover in
explosive atmospheres when the circuit is alive. All power to the transmitter is supplied over the
signal wiring.
2. Connect the lead that originates at the positive side of the power supply to the terminal marked “+”
and the lead that originates from the negative side of the power supply to the terminal marked “–”.
Avoid contact with the leads and terminals. Do not connect the powered signal wiring to the test
terminals. Power could damage the test diode in the test connection.
See
“Safety messages” on page 25
for warning information.
3. Plug and seal unused conduit connections on the transmitter housing to avoid moisture
accumulation in the terminal side of the housing. If you do not seal the unused connections, mount
the transmitter with the electrical housing positioned downward for drainage. Install wiring with a
drip loop. Arrange the drip loop so the bottom is lower than the conduit connections and the
transmitter housing.
Note
Signal wiring needs to be shielded, but use twisted pairs for best results. To ensure proper
communication, use 24 AWG or larger wire, and do not exceed 5000 feet (1500 meters).
Do not use inductive-based transient protectors, including the Rosemount 470, as they can adversely
affect the output of Rosemount 3051N 4–20 mA transmitters.The Rosemount 3051N includes the
transient protection terminal block (T1) as standard.
Signal wiring grounding
Do not run signal wiring in conduit or open trays with power wiring, or near heavy electrical equipment.
Ground the signal wiring at any one point on the signal loop, or leave it ungrounded. The negative
terminal of the power supply is a recommended grounding point.
Communication requires a minimum loop resistance of 250 ohms.
Max. Loop Resistance = 43.5 (Power Supply Voltage – 10.5) ohms
0
500
1000
1500
1935
10.5
20
30
40
55
L
oad (ohms)
Voltage (V dc)
Design
Region
Содержание Rosemount 3051N
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