Calibration Procedure

Download Calibration Procedure

Post on 16-Dec-2015

14 views

Category:

Documents

5 download

Embed Size (px)

DESCRIPTION

descripcion proceso de calibracion

TRANSCRIPT

<ul><li><p>Calibration Procedure Copyright 2013 Eagle Research Corporation Page | 1 </p></li><li><p>Calibration Procedure Copyright 2013 Eagle Research Corporation Page | 2 </p><p> 1999-2005 Eagle Research Corporation. All rights reserved. </p><p> This manual is for informational purposes only. Eagle Research Corporation MAKES NO </p><p>WARRANTIES, EXPRESSED OR IMPLIED, IN THIS MANUAL. </p><p>XARTU, XARTU/1, XARTU/5, XA-Series. LDVI, RtPM, SCI, TALON, and Field Manager are either registered trademarks, or trademarks of Eagle Research Corporation in the United States and/or </p><p>other countries. </p><p>CALIBRATION PROCEDURE (MVDP) Multivariable Differential Pressure Transmitter with an XARTU/1 </p><p>CONTENTS </p><p>INTRODUCTION ............................................................................................................................. 3 </p><p>SAFETY CONCERNS ........................................................................................................................ 3 Atmosphere .............................................................................................................................. 3 Arcing ........................................................................................................................................ 3 High Pressure ........................................................................................................................... 3 Safety Gear ............................................................................................................................... 4 </p><p>FIVE-VALVE MANIFOLD ................................................................................................................... 4 KEYPAD / DISPLAY .......................................................................................................................... 5 CALIBRATION METHODS .................................................................................................................. 6 </p><p>STANDARD CALIBRATION METHOD .......................................................................................... 7 </p><p>CONNECTING THE INSTRUMENT ....................................................................................................... 7 FUNCTION KEYS ............................................................................................................................. 8 CALIBRATING THE MVDP TRANSMITTER STANDARD METHOD .................................................. 9 </p><p>Calibrating the Static Pressure STANDARD METHOD ........................................................ 9 Setting ZERO Static Pressure .......................................................................................................... 9 Setting SPAN Static Pressure ........................................................................................................ 10 </p><p>Calibrating the Differential Pressure STANDARD METHOD .............................................. 11 Setting ZERO Differential Pressure ................................................................................................ 11 Setting SPAN Differential Pressure ................................................................................................ 12 </p><p>MULTI-POINT CALIBRATION METHOD ..................................................................................... 13 </p><p>OPENING MULTI-POINT CALIBRATION WITH FIELD MANAGER ....................................................... 14 CONNECTING THE INSTRUMENT ..................................................................................................... 16 CALIBRATING THE MVDP TRANSMITTER MULTI-POINT METHOD ............................................. 17 </p><p>Calibrating the Static Pressure MULTI-POINT METHOD ................................................... 18 Setting ZERO Static Pressure ........................................................................................................ 20 Setting SPAN Static Pressure ........................................................................................................ 22 </p><p>Calibrating the Differential Pressure MULTI-POINT METHOD ........................................... 24 Setting ZERO Differential Pressure ................................................................................................ 24 Setting SPAN Differential Pressure ................................................................................................ 25 </p><p>RETURNING THE UNIT TO SERVICE ......................................................................................... 27 </p></li><li><p>Calibration Procedure Copyright 2013 Eagle Research Corporation Page | 3 </p><p>Introduction The Multivariable Differential Pressure Transmitter (MVDP), typically attached to the bottom of the XARTU field computer, will measure the pressures across an orifice flow plate, and provide the differential pressure it sees to circuitry for signal output. The MVDP also sends a static pressure value to circuitry as a separate signal out. These two signals are the primary components used in orifice flow calculations. Along with a separate temperature signal and other values, accurate corrected flow measurement can be accomplished. Proper calibration of the MVDP is therefore necessary to achieve dependable readings. Calibration Mode, a built-in component of the XARTU programming, allows the user to calibrate the analog inputs such as differential pressure, static pressure, and temperature. While operating in the calibration mode the RTU continues to update volume. The analog input value used for calculations is the value measured when calibration mode was initially entered. Once in calibration mode, the user can perform the following operations: </p><p> Calibrate zero only Calibrate both zero and span </p><p> XARTU/1 calibration is software based, eliminating the need for the laborious and time-consuming requirement of repetitive potentiometer adjustments, and thereby simplifying the field calibration procedures. Safety Concerns Atmosphere When working on or near pipelines carrying combustible gasses or liquids, exercise extreme caution. Make sure all ports, valves, and other fittings are securely sealed, and that no unintended leaks are present. Never smoke or use ignition sources or fire near pipe and process lines that are not purged. </p><p> Arcing In conjunction with the statement on Atmosphere, be cautious using tools that may create a spark when struck or dropped. It is recommended that you use non-arcing tools for the work, and that you wear clothing that does not easily hold a static charge. Another source of arcing is the connection and disconnection of cables and other wiring. </p><p> High Pressure Always exercise caution when working with high pressure lines and equipment. Never apply high pressure to a line until all fittings are secured, and you are at that point in the procedure requiring it. Upon completion of any steps requiring high pressure, purge the test lines before moving on to the next step. </p></li><li><p>Calibration Procedure Copyright 2013 Eagle Research Corporation Page | 4 </p><p>Safety Gear It is recommended that eye protection be used when perfoming tests on equipment requiring the use of high pressure, and that ear protection be used during times when high pressures are being purged. </p><p> Five-Valve Manifold This procedure is based on the use of a Five-Valve Instrument Manifold. This device greatly improves control and convenience when using differential transmitters, and is strongly recommended. The High (upstream) side of the MVDP is typically to the left, as you face the front, with the low side at right. An example installation is shown below (note that your manifold may have a different appearance than that shown). </p><p>Figure 1 XARTU Typical Valving Arrangement </p></li><li><p>Calibration Procedure Copyright 2013 Eagle Research Corporation Page | 5 </p><p> Keypad / Display This procedure is written around the use of: 1) an internal Keypad/Display, 2) an external Keypad/Display, or 3) Virtual Keypad included in the Meter Reader Software. If using a physical Keypad/Display, plug it into one of the I2C expansion headers as shown below at upper left. </p><p>Figure 2 XARTU/1 Processor Board Detail</p></li><li><p>Calibration Procedure Copyright 2013 Eagle Research Corporation Page | 6 </p><p> Figure 3 XARTU Keypad Layout </p><p>Calibration Methods The MVDP transmitter may be calibrated using one of two methods: Standard Calibration Multi-Point Calibration </p><p> Standard Calibration has the advantage of being done using only a pressure source, calibration gauges, and a local keypad/display - eliminating the need for Eagles Talon or Field Manager program and a computer. It is accurate, but somewhat more laborious than when using Multi-Point Calibration. Multi-Point Calibration takes advantage of automated software controls to guide you through the procedure, reducing the chance of error and oversight, and providing a more efficient method for calibrating the instrument. Talon or Field Manager software on a local computer is required for Multi-Point Calibration. Both methods will be described in the following sections. </p></li><li><p>Calibration Procedure Copyright 2013 Eagle Research Corporation Page | 7 </p><p> STANDARD CALIBRATION METHOD Connecting the Instrument NOTE: Though not necessary, it is recommended that a five-valve manifold be used both in regular service, and for calibration procedures. The following steps are based on the use of this manifold. CAUTION: If a five-valve manifold is NOT used to perform these procedures, AN EQUALIZED AND GAUGED TEST PRESSURE MUST BE APPLIED TO BOTH THE HIGH AND LOW INLETS OF THE MVDP UNIT FOR THE STATIC PRESSURE TEST! </p><p>1. Remove any electrical power from the RTU. </p><p>2. Using site valves isolate and disconnect any field pipeline connections from the 5-valve manifold. </p><p>3. Using suitable adapters, connect your pressure standard to the High side (typically the left side) of the manifold inlet port (SEE CAUTION ABOVE). Make sure all manifold valves are opened (full counter-clockwise), and that the pressure standard supply is of sufficient volume and pressure to accomplish the task. </p><p>4. The High and Low Side Shutoffs permit a path thru the manifold from the Inlet to the Outlet ports. The High and Low Side Bypass valves open a path from either side to a common center point, and to the Vent valve. The Vent valve permits exhaust of the common point to the atmosphere. With the Vent closed, and both Bypass valves open, the High and Low sides are tied together, and thus equalized. Either side may be independently isolated from, or opened to, Vent. </p><p> The Standard Calibration Method uses five primary buttons on the keypad for calibrating the DP, P and T process variables, plus the numeric keypad digits 0 9. When the RTUs calibration mode is entered, it will freeze the last analog sample of the process variables and continue to calculate volumes using those values until the calibration mode is completed or exited. </p></li><li><p>Calibration Procedure Copyright 2013 Eagle Research Corporation Page | 8 </p><p>The five keypad buttons required for calibration are as described below: cal - Freezes the last process variable sample for calculation and places the unit into calibration mode. zero - Sets the Zero point in the calibration procedure. ent - Saves the current value or exits the current section of the procedure. span - Takes the user to the full-scale span point of the transducer being calibrated. esc - Takes the user out of the current calibration sequence and returns the unit to the run mode. </p><p>Function Keys The XARTU software permits the assignment of Function keys F0 F9 to facilitate quick access to such items as Differential Pressure (DP), Pressure (P), Temperature (T), and Volume (V). Typically F1 is assigned to Volume, F2 to Pressure, F3 to Differential Pressure, and F4 to Temperature in factory-installed configurations. If your company has standardized the RTU differently, please make the necessary substitutions as you work through this Calibration Process. If you have specific documentation you may wish to complete the Table below for future reference and use during Calibration Procedures. </p><p>Function Key Default </p><p>Function Key Our Company </p><p>Description </p><p>F0 </p><p>F1 Volume #1 </p><p>F2 Pressure #1 </p><p>F3 Differential Pressure #1 </p><p>F4 Temperature #1 </p><p>F5 </p><p>F6 </p><p>F7 </p><p>F8 </p><p>F9 </p><p> Figure 4 Function Key Cross-Reference Table </p><p> The XARTU /1 uses the five special keys plus the 0 9 numeric keys to accomplish all of the calibration tasks. </p></li><li><p>Calibration Procedure Copyright 2013 Eagle Research Corporation Page | 9 </p><p>Calibrating the MVDP Transmitter STANDARD METHOD **CAUTION** Be careful in applying pressure to the unit under test! Assure that all fittings are securely made up, and that pressures applied are within the established limits of the transducer range. Have a quick method handy to shut off pressure in the event of a hazard or an overpressure. </p><p>Calibrating the Static Pressure STANDARD METHOD </p><p>Static Pressure is calibrated first. Begin by setting all valves as shown: Close (turn CW) both main Shutoff valves and the Vent valve. Open (CCW) both Bypass valves. This will assure that equalized pressure will be placed on both sides of the Differential Pressure element inside, and damage does no occur. CAUTION applying high pressure to the unit with either bypass valve closed can damage the differential element. NOTE repeatedly pressing the esc button on the keypad at any time will exit the calibration procedure. </p><p>Setting ZERO Static Pressure </p><p>1. Apply operating power to the RTU (see its Installation and Operating Manual). </p><p>2. Press Function Key F3 to display the live Pressure window (remember to consult your cross-reference table if different). </p><p>3. Apply full pressure to the High Inlet port, according to the established range of the MVDP. </p><p>4. Open the High Side Shutoff valve. </p><p>5. Check for leaks while allowing the unit to stress for about 45-60 seconds. </p><p>6. Close the High Side Shutoff valve, and Open the Vent valve. </p><p>7. Press the blue cal key on the units keypad to enter Calibration Mode. If the unit being calibrated requires a password, you must enter it now at the PASSWORD? prompt. The display will now alternate between CALIBRATING and the parameter label in this case PRESSURE #1. </p><p>8. Allow the reading to stabilize on the display and press zero on the keypad: </p><p> ZERO&gt; XX.XX NEW?&gt; . </p></li><li><p>Calibration Procedure Copyright 2013 Eagle Research Corporation Page | 10 </p><p> 9. XX.XX represents the current value of the parameter being calibrated. </p><p>10. On the keypad, type in 0.00 and ent (or simply ent) if 0.00 is already there. The display will show Calculating. Briefly, then display the new point. </p><p> Zero for the unit is now set, and you may...</p></li></ul>

Recommended

View more >