Emerson 3051N User Manual

Reference Manual 

00809-0100-4808, Rev CA
June 2008

2-5

Rosemount 3051N

To commission on the bench, connect the transmitter and the communicator 
as shown in Figure 2-3. Make sure the instruments in the loop are installed in 
accordance with intrinsically safe or nonincendive field wiring practices before 
connecting a communicator in an explosive atmosphere. Connect the 
communicator leads at any termination point in the signal loop. It is most 
convenient to connect them to the terminals labeled “COMM” on the terminal 
block. Connecting across the “TEST” terminals will prevent successful 
communication. To avoid exposing the transmitter electronics to the plant 
environment after installation, set all transmitter jumpers during the 
commissioning stage on the bench.

For 4–20 mA transmitters, you will need a power supply capable of providing 
10.5 to 55 V dc at the transmitter, and a meter to measure output current. To 
enable communication, a resistance of at least 250 ohms, but within the 
transmitter load limitations (see Figure 3-7 “Power Supply Load Limitations.” 
in Section 3) must be present between the communicator loop connection and 
the power supply. Do not use inductive-based transient protectors with the 
Rosemount 3051N.

Setting the Loop to 
Manual

Whenever you are preparing to send or request data that would disrupt the 
loop or change the output of the transmitter, you must set your process 
application loop to manual. The HART Communicator will prompt you to set 
the loop to manual when necessary. Keep in mind that acknowledging this 
prompt does not set the loop to manual. The prompt is only a reminder; you 
have to set the loop to manual yourself as a separate operation.

Wiring Diagrams 
(Bench Hook-up)

Connect the bench equipment as shown in Figure 2-3 and turn on the 
HART-based Communicator by pressing the ON/OFF key. The communicator 
will search for a HART-compatible device and will indicate when the 
connection is made. If the communicator fails to connect, it will indicate that 
no device was found. If this occurs, refer to Section 4: Troubleshooting.

FIGURE 2-3. Bench Hook-up
(4–20 mA Transmitters).

See “Safety Messages” on page 2-1 for warning information.

≥

Ω