Step 5: Connect Wiring And Power Up - Emerson Rosemount 3051S Quick Installation Manual

Quick Installation Guide
00825-0100-4804, Rev AB
January 2011
S 5: C
TEP ONNECT
A 3051S ERS System can be wired in a variety of configurations, depending on the hardware
that was ordered.
Standard 3051S ERS System (Figure 8)
1. Remove the housing cover labeled "Field Terminals" on both 3051S ERS sensors.
2. Using the 3051S ERS communication cable (if ordered) or an equivalent 4-wire shielded
assembly per the specifications detailed below, connect the 1, 2, A, and B terminals between
the two sensors per Figure 8.
3. Connect the 3051S ERS system to the control loop by connecting the + and - PWR / COMM
terminals to the positive and negative leads, respectively.
4. Plug and seal all unused conduit connections.
5. If applicable, install wiring with a drip loop. Arrange the drip loop so that the bottom is lower
than the conduit connections on the transmitter housings.
6. Reinstall and tighten the housing covers on both sensors so that metal contacts metal to meet
explosion-proof requirements.
3051S ERS System with Remote Display and Interface (Figure 9 and Figure 10)
1. Remove the housing cover labeled "Field Terminals" on both 3051S ERS sensors and the
remote housing.
2. Using the 3051S ERS communication cable (if ordered) or an equivalent 4-wire shielded
assembly per the specifications detailed below, connect the 1, 2, A, and B terminals between
the two sensors and remote housing in a "tree" (Figure 9) or "daisy-chain" (Figure 10)
configuration.
3. Connect the 3051S ERS system to the control loop by connecting the + and - PWR / COMM
terminals on the remote housing to the positive and negative leads, respectively.
4. Plug and seal all unused conduit connections.
5. If applicable, install wiring with a drip loop. Arrange the drip loop so that the bottom is lower
than the conduit connections on the transmitter housings.
6. Reinstall and tighten all housing covers so that metal contacts metal to meet explosion-proof
requirements.
Wiring Diagrams
Figure 8 - Figure 10 show the wiring connections necessary to power a 3051S ERS System and
enable communications with a hand-held Field Communicator.
NOTE
The wiring connection between the sensors (and remote housing if applicable) must be made
directly. An intrinsically safe barrier or other high-impedance device will cause the 3051S ERS
system to malfunction if placed in between any of the 3051S ERS sensors.
3051S ERS Cable Specifications
Cable Type: Recommend Madison AWM Style 2549 cable. Other comparable cable may be
used as long as it has independent dual twisted shielded pair wires with an outer shield. The
Power wires (pin terminals 1 & 2) must be 22 AWG minimum and the communication wires (pin
terminals A & B) must be 24 AWG minimum.
Cable Length: Up to 100 feet (31 m) depending upon cable capacitance.
Cable Capacitance: The capacitance between the communication terminals (pin terminals A &
B) as wired must be less than 5000 picofarads total. This allows up to 50 picofarads per foot (0.3
m) for a 100 foot (31 m) cable.
Cable Outside Diameter (O.D): 0.270 inches (6.86 mm)
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