Emerson 3051N manual Process Connections Housing Rotation, ELECTRICAL CONSIDERATIONS Power Supply

Rosemount 3051N

Reference Manual

00809-0100-4808, Rev CA June 2008

Process Connections

Housing Rotation

ELECTRICAL CONSIDERATIONS

Power Supply

Rosemount 3051N connections on the transmitter flange are 1/4–18 NPT. Use your plant-approved lubricant or sealant when making the connections. The end-user is responsible for the qualification of the threaded seal interface on the transmitter’s 1/4-18 NPT connections.

Do not attempt to loosen or remove the flange bolts while the transmitter is in service.

The electronics housing can be rotated up to 180 degrees (left or right) to improve field access or to better view the optional LCD meter. To rotate the housing, perform the following procedure:

1.Loosen the housing rotation set screw using a 9/64-in. hex wrench.

2.Turn the housing up to 180 degrees to the left or right of its original (as shipped) position. Do not rotate the housing more than 180 degrees.

Over-rotation will sever the electrical connection between the sensor module and the electronics module.

3.Retighten the housing rotation set screw.

The transmitter terminal block is in the compartment of the electronics housing labeled “FIELD TERMINALS.” The other compartment contains the transmitter electronics module. Connections for the HART-based communicator are attached beneath the terminal screws on the terminal block. Figure 3-7shows power supply load limitations for the transmitter.

4–20 mA Transmitters

The dc power supply should provide power with less than 2 percent ripple. The total resistance load is the sum of the resistance of the 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.

NOTE

A minimum loop resistance of 250 ohms is required to communicate with a HART-based communicator. With 250 ohms of loop resistance, the transmitter will require a minimum of 16 volts to output 20 mA. If a single power supply is used to power more than one Rosemount 3051N transmitter, the power supply used, and circuitry common to the transmitters, should not have more than 20 ohms of impedance at 1200 Hz. For additional details, see Figure 3-7 "Power Supply Load Limitations."

See “Safety Messages” on page 3-1for warning information.

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