K-Tec manual Appendix D Interface Applications, MT2000 Interface

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LRV=(A+ML) * ÖOILdc
URV=A * ÖOILdc

9.4 APPENDIX D: Interface Applications

MT2000 Interface

 

 

It is possible to use an MT2000 to determine the level of an interface but certain require-

 

ments must be met:

 

1.

The dielectric constant of the upper liquid must be low (between 2 and 3).

 

2.

The dielectric constant of the lower liquid must be higher than the upper liquid (10 or

 

 

greater).

A

3.

The interface layer must be contained within a few inches.

 

4.

A means of venting all vapor/gas from the top of the chamber must be available.

 

5.The standard MT2000 can only measure the interface of two liquids in a completely flooded chamber. For interface measurements with vapor space above the upper fluid, the MT2000 interface option must be used. Refer to the MT2000 Total and Interface

Level Transmitter Data Sheet on the K-TEK website (www.ktekcorp.com).

ML OIL

CAUTION:

1.If the dielectric constant of the upper phase varies it will have an impact on the accuracy of the measurement. Should it change significantly it can be necessary

 

to re-trim the MT2000. Refer to Appendix A for the Sensor Trim information.

 

2.

If the chamber does not remain totally flooded the interface measurement will not

Wa-

 

 

be correct.

 

3.

A means of venting all vapor/gas must be incorporated. This is typically accom-

Figure 9.3

 

plished by installing a “bleed ring” between the top flange on the chamber and

the MT2000.

4.A means of moving the interface between two known points is extremely beneficial, and is generally ac- complished using “drain rings” at the upper and lower process connections. This will allow setting 0% and 100% interface levels at the transmitter to make calibration (and resetting sensor trim if needed) much more accurate.

5.The MT2000 can only measure the interface between two liquids be operated in a chamber or vessel that MUST remains completely flooded. If this condition is not met, the measurement will be invalid. If the installation will have a vapor space continuously present in top of the chamber the M4AI module (MT2000 interface module) must be used. Refer to the MT2000 Total and Interface Level Transmitter Data Sheet on the K-TEK website (www.ktekcorp.com).

As discussed in the Ultra Low Dielectric Mode (ULD) section, the signal’s rate of propagation, or time of flight, changes when passing through a low dielectric product. Using this concept and the response of the MT2000 in a high dielectric, an interface level can be determined and tracked. In order to setup the calibration range of the trans- mitter, one of the following needs to be available: the dielectric constant of the upper liquid, the actual level of the product, or the ability to manipulate the product. If the dielectric constant of the upper liquid is known, the calibration points can be determined using the formulas from the ULD mode. As shown in drawing (A), the LRV can be deter- mined with the formula LRV=(A+ML) * (Ödc). The URV can be determined using the formula URV=A * (Ödc).

If the dielectric constant of the upper level is not known but the actual level is known. Using the same concept as above we can reverse calculate the dielectric constant and then determine the LRV and URV. For instance, if the actual interface level was at point A on the example figure on this page with that dimension being 6 inches and the displayed measurement from the transmitter was 8.5 inches. Divide the displayed value by the actual value (8.5/6= 1.416). Squaring this answer will result in the dielectric constant of the product (1.4162 = 2.00). Now that the dielec- tric constant is known, the LRV and URV can be set using the previous formulas.

If the level can be manipulated, the calibration points can be set using the push buttons. One thing to note at this point is that the calibration points are not going to match the actual liquid level and may be confusing to some cus- tomers. In addition, the range of the calibration will not correspond to the actual measured movement of the level. To compensate for this, the transmitter can be re-trimmed in process if the level can be manipulated. Note that the 38 raw counts per inch will change when this is done. It may also be necessary to re-trim the unit if the LRV falls at an unacceptable level (recognized by flashing numbers on the LRV screen). This can occur if the probe is short or the dielectric constant of the upper liquid is higher than 2.

K-TEK recommends that the EC or other chamber used have a vent and drain to truly set the interface at real world points (in other words fill to the upper connection with water and then drain the water down till the oil water interface is at the CL of the lower nozzle).

MT2000-0200-1 Rev f (10-2007) DCN0160

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Contents Guided Wave Radar Level Transmitter Table of Contents Appendices List of FiguresIntroduction Measurement cycle consists of the following Ambient TemperatureOverview Storage InformationUltra Low Dielectric ULD Measure Method Direct Reflect Mode standard cont’dMounting Requirements InstallationURV = Probe Length LRV = 0 in. / 0 mm Factory Default ConfigurationShortening of Probe MT2000 Guided Wave Radar GuidelinesMT2000 Guided Wave Radar Guidelines cont’d WiringQuickstart Procedure CommissioningQuickstart Procedure cont’d Verify Proper Power-UpSetting the 4mA and 20 mA Points Using the Pushbutton Menu Calibration Menu LCD Menu OperationThreshold Level Parameter THV and Gain Setting GS Detailed Configuration Parameters Direct Mode Blanking MenuThreshold Level Parameter THV and Gain Setting GS cont’d Advanced Parameter SettingsL1O KO & KG Advanced Parameter Settings cont’dUltra Low Dielectric ULD Mode Configuration = H * Sqrt DC H + LDC = I + H L / H2 DAC TrimFigure Ultra Low Dielectric ULD Mode Configuration cont’dAdvanced Output Configuration Setting the DAC trimBench Calibration of the 4mA & 20mA Points 6 4mA & 20mA Calibration Using Actual Level InputJumper Switch Settings Reversing The Output Action Using Actual Level InputTroubleshooting Information Possible SymptomsValid Current Loop Outputs Interoperability and Conformance Class Possible Symptoms cont’dElectronics Module Replacement Honeywell DE Output OptionCompatibility Hart Protocol Interface OptionOperating Modes Hart CommunicatorLRV Glossary of TermsAppendix a Sensor Trim AppendicesEND CFG Menu Configuration 2 Hidden MenuTMP To clear the linearization table To access the linearization tableSetting up Linearization Table Points Appendix C LinearizationMT2000 Interface Appendix D Interface ApplicationsChannel B Use and setup of the oscilloscope for the MT2000Scope Settings Channel a PrerequisitesAppendix F CE Certificate of Conformity Appendix G Exida Certificate MT2000-0200-1 Rev f 10-2007 DCN0160 MT2000-0200-01 Rev f 10-2007 DCN0160 MT2000-0200-1 Rev f 10-2007 DCN0160 10b Appendix I Mounting Configurations3a, 3b 10aYear Warranty for Appendix J Warranty Statement
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