Emerson 00809-0100-4514, 1154 manual Conduit, Electrical Considerations

Page 16

Rosemount 1154

Reference Manual

00809-0100-4514, Rev BA January 2008

The piping between the process and the transmitter must transfer the pressure measured at the process taps to the transmitter. Possible sources of error in this pressure transfer are:

 

• Leaks

 

• Friction loss (particularly if purging is used)

 

• Trapped gas in a liquid line or trapped liquid in a gas line (head error)

 

• Temperature-induced density variation between legs (head error), for

 

differential transmitters

 

To minimize the possibility of errors, take the following precautions:

 

• Make impulse tubing as short as possible.

 

• Slope tubing at least one inch per foot up toward the process

 

connections for liquid and steam.

 

• Slope tubing at least one inch per foot down toward the process

 

connections for gas.

 

• Avoid high points in liquid lines and low points in gas lines.

 

• Use impulse tubing of sufficient diameter to avoid friction effects.

 

• Ensure that all gas is vented from liquid tubing legs.

 

• Ensure that impulse tubing is of adequate strength to be compatible

 

with anticipated pressures.

 

For differential transmitters, also consider the following:

 

• Keep both impulse legs at the same temperature.

 

• When using sealing fluid, fill both piping legs to the same level.

 

• When purging, make the purge connection close to the process taps

 

and purge through equal lengths of the same size tubing. Avoid purging

 

through the transmitter.

Conduit

The conduit connection to the transmitter is 1/2–14 NPT. Use a qualified

 

conduit seal at the conduit entry to prevent moisture from accumulating in the

 

terminal side of the housing during accident conditions. To prevent the conduit

 

from adding mechanical stress to the transmitter during seismic disturbances,

 

use flexible conduit or support the conduit near the transmitter. Install the

 

conduit seal in accordance with the manufacturer’s instructions or use the

 

procedure on page 2-8.

ELECTRICAL CONSIDERATIONS

This section contains information that you should consider when preparing to make electrical connections to the transmitter. Read this section carefully before proceeding to the electrical installation procedures.

The Rosemount 1154 pressure transmitter provides a 4–20 mA signal when connected to a suitable dc power source. Figure 2-2 on page 2-5shows a typical signal loop consisting of transmitter, power supply, and various receivers (controller, indicator, computer, etc.). The power supply must supply at least 12 volts to the transmitter terminals at 30 mA (overscale) signal, or the maximum output current required for proper system operation. Any power supply ripple appears in the output load. The supply voltage versus load limitation relationship is shown in Figure 2-3 on page 2-5.See qualification report D8400102 for details. The load is the sum of the resistance of the signal leads and the load resistance of the receivers.

2-4

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Contents Rosemount Reference ManualImportant Notice -- Errata Rosemount 1154 Alphaline Nuclear Pressure Transmitter Return of Material Changes From June 1999 to January Revision StatusNew Old Changes Rosemount Table of Contents Specifications Reference Data Maintenance TroubleshootingSection TOC-3 TOC-4 Section Introduction Overview About the TransmitterRosemount Section Installation Overview General ConsiderationsMechanical Considerations Process ConnectionsRosemount Conduit Electrical ConsiderationsTransmitter Wiring Connections Procedures InstallationMechanical Pressure Dimension Range CodeLiquid Service ElectricalTransmitter Terminal Block Rosemount Section Calibration Span Adjustment Zero AdjustmentOverview Calibration Calibration Procedures Zero and Span AdjustmentZero and Span Adjustment Screws Linearity Adjustment Damping Adjustment Linearity and Damping AdjustmentRosemount Calculate zero adjustment correction in terms of pressure Rosemount Section Operation Overview Transmitter OperationΔ-Cell Linearity Adjustment DemodulatorFV Iref Maintenance Troubleshooting OverviewSafety Messages Test Terminals Board CheckoutSensing Module Checkout Disassembly Procedure Process Flange RemovalRosemount 1154 Parts List Part DescriptionReassembly Procedure Rosemount Process Flange Reassembly Symptom Potential Source Corrective Action Post Assembly TestsOn Next Check for adequate voltage to the transmitter Specifications and Reference Data Nuclear SpecificationsPerformance Specifications Range Code Overpressure Effect Range Code Static Pressure Zero Effect Functional SpecificationsRange Code Response Time Range Code Pressure Ranges 25 to 0-150 inH2O 0-6.22 to 0-37.3 kPaPhysical Specifications Range Code Overpressure LimitRosemount Ordering Information Rosemount 1154DP, 1154HP, and 1154GP Spare Parts Rosemount 1154DP 1154HP 1154GP Part Description Order NoFor use with existing N0026 transmitter only Spare Parts Shelf Life Important Notice Rosemount Current Control Current Limit Index-2 Page ¢00809-XXXX-XXXX ¤
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