Micro Motion Enhanced Density Application Manuals & Guides

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Instruction Manual

P/N 20002315, Rev. A February 2005

Micro Motion

Enhanced Density Application

Theory, Configuration, and Use

Micro Motion

Enhanced Density Application

Theory, Configuration, and Use

For technical support, phone the support center nearest you:

• In U.S.A., phone 1-800-522-MASS (1-800-522-6277)

• In Canada and Latin America, phone (303) 527-5200

• In Asia, phone (65) 6770-8155

• In the U.K., phone 0800 - 966 180 (toll-free)

• Outside the U.K., phone +31 (0) 318 495 670

©2005, Micro Motion, Inc. All rights reserved. Micro Motion is a registered trademark of Micro Motion, Inc. The Micro Motion and Emerson logos are trademarks of Emerson Electric Co. All other trademarks are property of their respective owners.

Chapter 1 Before You Begin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.1 Purpose of manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.2 Terminology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.3 Transmitter interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.4 Procedures described in this manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Chapter 2 Enhanced Density Theory and Background . . . . . . . . . . . . . . . . . . . . 3

2.1 About this chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2.2 Enhanced density application overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2.3 Measuring density, specific gravity, and concentration . . . . . . . . . . . . . . . . . . . . . . . . 3

2.3.1 Definition of density, specific gravity, and concentration . . . . . . . . . . . . . . 3

2.3.2 Effects of temperature on density, specific gravity, and concentration. . . . 4

2.3.3 Calculating concentration from density . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2.4 Defining a Micro Motion enhanced density curve . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2.5 Enhanced density application example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Chapter 3 Loading a Standard or Custom Curve . . . . . . . . . . . . . . . . . . . . . . 13

3.1 About this chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

3.2 Standard and custom curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

3.3 Loading procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

3.3.1 Using ProLink II . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

3.3.2 Using the display on Series 3000 4-wire transmitters . . . . . . . . . . . . . . . 16

3.3.3 Using the display on Series 3000 9-wire transmitters . . . . . . . . . . . . . . . 17

Chapter 4 Configuring a User-Defined Curve. . . . . . . . . . . . . . . . . . . . . . . . . 19

4.1 About this chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

4.2 Measurement units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

4.3 Configuration steps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

4.3.1 Using ProLink II . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

4.3.2 Using the display on Series 3000 transmitters. . . . . . . . . . . . . . . . . . . . . 24

4.4 Curve fitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Chapter 5 Using an Enhanced Density Curve. . . . . . . . . . . . . . . . . . . . . . . . . 29

5.1 About this chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

5.2 Specifying the active curve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

5.2.1 Using ProLink II . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

5.2.2 Using the display on Series 3000 transmitters. . . . . . . . . . . . . . . . . . . . . 30

5.3 Using enhanced density process variables. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

5.4 Modifying the curve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

5.5 Saving a density curve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Enhanced Density Application: Theory, Configuration, and Use i

Contents continued

Chapter 6 Advanced Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

6.1 About this chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

6.2 Maximum order during curve fit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

6.3 Density curve trim . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

6.3.1 Offset trim . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

6.3.2 Slope and offset trim . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Appendix A Isotherm and Concentration Curve Ranges . . . . . . . . . . . . . . . . . . 37

A.1 About this appendix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

A.2 Fewer versus more points. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

A.3 Fewer versus more points, and required ranges. . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Appendix B Configuration Records . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

B.1 About this appendix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

B.2 Electronic versus paper configuration records . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

B.3 Derived variable: Density at reference temperature . . . . . . . . . . . . . . . . . . . . . . . . . 41

B.4 Derived variable: Specific gravity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

B.5 Derived variable: Mass Conc (Dens) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

B.6 Derived variable: Mass Conc (SG) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

B.7 Derived variable: Volume Conc (Dens) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

B.8 Derived variable: Volume Conc (SG) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

B.9 Derived variable: Conc (Density) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

B.10 Derived variable: Conc (SG) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

ii Enhanced Density Application: Theory, Configuration, and Use

Chapter 1

Before You Begin

1.1 Purpose of manual

This manual is designed to provide two types of information: how the enhanced density application works, and how to configure and use the enhanced density application.

1.2 Terminology

• Enhanced density curve – A three-dimensional surface that describes the relationship between temperature, concentration, and density.

• Standard curves – A set of curves that are supplied by Micro Motion as part of the enhanced density application, and are suitable for use in many processes. These curves are listed and described in Chapter 3.

• Custom curve – A curve that has been built by Micro Motion according to customer requirements.

• User-defined curve – A curve built by a customer, using the enhanced density application.

Theory and Background User-Defined CurvesStandard or Custom CurvesBefore You Begin

1.3 Transmitter interfaces

Depending on your transmitter, one or more of the following interfaces is available for the enhanced density application:

• ProLink II – available for all transmitters except the Series 3000 9-wire

• PocketProLink – available for all transmitters except the Series 3000 9-wire

• The display (PPI) on the Series 3000 9-wire (ALTUS) transmitter

• The display (PPI) on the Series 3000 4-wire (MVD) transmitter

This manual shows the ProLink II interface and the Series 3000 display interfaces. The PocketProLink interface is similar to the ProLink II interface.

1.4 Procedures described in this manual

There are two configuration procedures:

• If you purchased the standard curves or one or more custom curves, all you need to do is to load the curve(s) into a transmitter slot. Instructions for loading a curve into a slot are provided in Chapter 3.

• If you did not purchase standard or custom curves, you can configure your own curve(s), using your own process data. Instructions for configuring a user-defined curve are provided in Chapter 4.

Enhanced Density Application: Theory, Configuration, and Use 1

Before You Begin continued

After all curves have been loaded or defined, the active curve must be specified. Minor customization of the curve is possible. The enhanced density application is now available for use in transmitter configuration. Instructions for specifying the active curve, modifying a curve, and using a curve are provided in Chapter 5.

The optional density curve trim is described in Chapter 6.

2 Enhanced Density Application: Theory, Configuration, and Use

Chapter 2

Enhanced Density Theory and Background

2.1 About this chapter

This chapter provides a conceptual overview of the relationship between density and concentration and how concentration can be calculated from density. Additionally, this chapter discusses how this calculation is implemented in the enhanced density application. Finally, this chapter provides an example of enhanced density used in a real-world application.

Note: This chapter does not provide configuration instructions. For assistance with loading a standard or custom curve provided by Micro Motion, see Chapter 3. For instructions on configuring a user-defined curve, see Chapter 4.

2.2 Enhanced density application overview

Micro Motion sensors provide direct measurements of density, but not of concentration. The enhanced density application calculates enhanced density variable,s such as concentration or density at reference temperature, from density process data, appropriately compensated for temperature.

Theory and Background User-Defined CurvesStandard or Custom CurvesBefore You Begin

The derived variable, specified during configuration, controls the type of concentration measurement that will be produced (see Section 2.3.1). Each derived variable allows the calculation of a subset of enhanced density process variables (see Table 2-1). The available enhanced density process variables can be used in process control, just as mass, volume, and other process variables are used. For example, an event can be defined on an enhanced density process variable.

2.3 Measuring density, specific gravity, and concentration

Density, specific gravity, and concentration are central concepts in the enhanced density application. This section defines these terms and describes the characteristics that are relevant to the enhanced density application.

2.3.1 Definition of density, specific gravity, and concentration

Density is a measure of mass per unit volume. Density measurements apply to both pure substances such as mercury or silver and compounds such as air and water. Typical density units include:

•kg/m

•g/cm

• lb (mass)/ft

• lb (mass)/gal

Enhanced Density Application: Theory, Configuration, and Use 3

Enhanced Density Theory and Background continued

Specific gravity is the ratio of two densities:

Density of Process Fluid at Reference Temperature T1

-------------------------------------------------------------------------------------------------------------------------------------------------------

Density of Reference Fluid at Reference Temperature T2

Water is typically used as the reference fluid. The T1 and T2 temperature values may be different. Specific gravity has no units. The following reference temperature combinations are frequently used to calculate specific gravity:

• SG20/4 – Process fluid at 20 °C, water at 4 °C (density = 1.0000 g/cm

• SG20/20 – Process fluid at 20 °C, water at 20 °C (density = 0.9982 g/cm

• SG60/60 – Process fluid at 60 °F, water at 60 °F (density = 0.9990 g/cm

Concentration describes the quantity of one substance in a compound in relation to the whole, for example, the concentration of salt in salt water. Concentration is typically expressed as a percentage. Concentration can be based on mass or volume:

-----------------------------------------------------------

Total Mass of Solution

Volume of Solute

-----------------------------------------------------------------

Total Volume of Solution

Mass of Solute

)

Typical concentration units include:

• Degrees Plato

• Degrees Balling

•Degrees Brix

• Degrees Baume (light or heavy)

• Degrees Twaddell

• %Solids/Mass

• %Solids/Volume

•Proof/Mass

• Proof/Volume

2.3.2 Effects of temperature on density, specific gravity, and concentration

Density always changes with temperature; as temperature increases, density decreases (for most substances). See Figure 2-1. The amount of change is different for different substances.

4 Enhanced Density Application: Theory, Configuration, and Use

Enhanced Density Theory and Background continued

Figure 2-1 Density affected by temperature

Temperature = 4 °C Temperature = 25 °C

100 kilograms

100.0 liters Density at 4

°C = 1000 kg/m

100 kilograms

100.3 liters Density at 25

°C = 997 kg/m

Specific gravity does not vary with changing temperature, because it is defined at reference temperatures.

When concentration is measured, the solute and the solvent typically have different responses to temperature, that is, one expands more than the other as temperature increases. Therefore:

• Concentration values based on mass are not affected by temperature. This is the most common type of concentration measurement. See Figure 2-2.

• Concentration values based on volume are affected by temperature. These concentration measurements are rarely used, with the exception of the distilled spirits industry (proof is a concentration measurement based on volume).

Figure 2-2 Concentration not affected by temperature

Theory and Background User-Defined CurvesStandard or Custom CurvesBefore You Begin

55 kg sucrose 45 kg water 100 kg sucrose solution

55 °Brix concentration

at all temperatures

Enhanced Density Application: Theory, Configuration, and Use 5

Enhanced Density Theory and Background continued

Because of these temperature effects, there is not a one-to-one relationship between density and concentration (see Figure 2-3). A three-dimensional surface – concentration, temperature, and density – is required. This three-dimensional surface is the enhanced density curve. Different process fluids have different enhanced density curves. A typical enhanced density curve is shown in Figure 2-4.

Figure 2-3 Relationship between density and concentration at two different temperatures

1.8

1.6

)

1.4

1.2

Density (g/cm

1.0

Temperature 1

Temp 1

Temperature 2

Temp 2

0.8

0 50 100

Figure 2-4 Example density curve

1.6

1.5

1.4

1.3

Y axis:

Density

1.2

1.1

Concentration (%)

100

Z axis: Temperature

1.0 12

X axis: Concentration

6 Enhanced Density Application: Theory, Configuration, and Use

Enhanced Density Theory and Background continued

2.3.3 Calculating concentration from density

There are two main steps in calculating concentration (see Figure 2-5):

1. Applying temperature correction to density process data. This step maps the current point on the enhanced density surface to the equivalent point on the reference temperature isotherm, producing a density-at-reference-temperature value.

2. Converting the corrected density value to a concentration value. Because all density values have been corrected for temperature, any change in density must be a result of change in composition of the process fluid, and a one-to-one conversion can be applied.

The enhanced density curve data stored in the transmitter contains the coefficients required to collapse the surface to the density-at-reference-temperature curve, and to map that curve to the concentration axis.

Figure 2-5 Enhanced density calculations

1.6

1.5

1.4

1.3

Y axis:

Density

1.2

1.1

1.0

X axis: Concentration

100

Theory and Background User-Defined CurvesStandard or Custom CurvesBefore You Begin

Reference temperature isotherm

Z axis: Temperature

2.4 Defining a Micro Motion enhanced density curve

This section provides a conceptual overview of the process of defining an enhanced density curve. Specific configuration instructions are provided for standard or custom curves in Chapter 3, and for user-defined curves in Chapter 4.

There are five steps involved in defining an enhanced density curve:

• Specifying the derived variable

• Specifying required reference values

• Defining the enhanced density surface

• Mapping density at reference temperature to concentration

• Curve fitting

Enhanced Density Application: Theory, Configuration, and Use 7

Enhanced Density Theory and Background continued

Step 1 Specifying the derived variable

The enhanced density application can calculate concentration using any of several different methods, for example, mass concentration derived from reference density, or volume concentration derived from specific gravity. The method used, and therefore the concentration measurement in effect, is determined by the configured “derived variable.”

Depending on the specified derived variable, different enhanced density process variables are available for use in process control. Table 2-1 lists the derived variables and the available process variables for each derived variable. Be sure that the derived variable you choose will provide the enhanced density process variables required by your application, and can be calculated from the data that you have.

Note: All “net” process variables assume that the concentration data is based on percent. This includes Net mass flow rate, Net volume flow rate, and the related totals and inventories. If you will be using a “net” process variable for process measurement, ensure that your concentration values are based on percent solids.

Table 2-1 Derived variables and available process variables

Available process variables

Derived variable – ProLink II label and definition

Density @ Ref

Density at reference temperature

Mass/unit volume, corrected to a given reference temperature

Specific gravity

The ratio of the density of a process fluid at a given temperature to the density of water at a given temperature. The two given temperature conditions do not need to be the same

Mass Conc (Dens)

Mass concentration derived from reference density

The percent mass of solute or of material in suspension in the total solution, derived from reference density

Mass Conc (SG)

Mass concentration derived from specific gravity

The percent mass of solute or of material in suspension in the total solution, derived from specific gravity

Volume Conc (Dens)

Volume concentration derived from reference density

The percent volume of solute or of material in suspension in the total solution, derived from reference density

Density at reference temperature

✓✓

✓✓✓

✓✓ ✓ ✓

✓✓✓✓ ✓

✓✓ ✓ ✓

Standard volume flow rate

Specific gravity

Concentration Net

mass flow rate

Net volume flow rate

8 Enhanced Density Application: Theory, Configuration, and Use

Enhanced Density Theory and Background continued

Table 2-1 Derived variables and available process variables (continued)

Available process variables

Derived variable – ProLink II label and definition

Volume Conc (SG)

Volume concentration derived from specific gravity

The percent volume of solute or of material in suspension in the total solution, derived from specific gravity

Conc (Dens)

Concentration derived from reference density

The mass, volume, weight, or number of moles of solute or of material in suspension in proportion to the total solution, derived from reference density

Conc (SG)

Concentration derived from specific gravity

The mass, volume, weight, or number of moles of solute or of material in suspension in proportion to the total solution, derived from specific gravity

Density at reference temperature

✓✓✓✓ ✓

✓✓ ✓

✓✓✓✓

Standard volume flow rate

Specific gravity

Concentration Net

mass flow rate

Net volume flow rate

Theory and Background User-Defined CurvesStandard or Custom CurvesBefore You Begin

Step 2 Specifying required reference values

Depending on the derived variable, different reference values are required for the enhanced density calculation. Table 2-2 lists and defines the reference values that may be required. Table 2-3 lists the derived variables and the reference values that each requires.

Table 2-2 Reference value definitions

Reference value Definition

Reference temperature of process fluid The temperature to which density values will be corrected

Reference temperature of water The T2 temperature value to be used in calculating specific gravity

Reference density of water The density of water at the T2 reference temperature

Table 2-3 Derived variables and required reference values

Reference values

Reference temperature

Derived variable

Density @ Ref ✓

SG ✓✓✓

Mass Conc (Dens) ✓

Mass Conc (SG) ✓✓✓

Volume Conc (Dens) ✓

Volume Conc (SG) ✓✓✓

Conc (Dens) ✓

Conc (SG) ✓✓✓

of process fluid

Reference temperature of water

Reference density of water

Enhanced Density Application: Theory, Configuration, and Use 9

Enhanced Density Theory and Background continued

Step 3 Defining the enhanced density surface

The enhanced density surface provides the information required to perform temperature correction on density process data, that is, to map process density values to density at reference temperature. To define the enhanced density surface:

1. Specify 2 to 6 temperature values that will define the temperature isotherms

2. Specify 2 to 5 concentration values that will define the concentration curves

3. For each data point (intersection of a temperature isotherm with a concentration curve), specify the density of the process fluid at the corresponding temperature and concentration. For example, to define the enhanced density surface shown in Figure 2-6, with 6 temperature isotherms and 5 concentration curves, you must specify the density of the process fluid at Concentration A and Temperature 1, at Concentration A and Temperature 2, and so on through Concentration E and Temperature 6.

Figure 2-6 Example density curve

Concentration curves A–E

1.6

1.5

1.4

1.3

Y axis:

Density

1.2

1.1

1.0 12

X axis: Concentration

100

Z axis: Temperature

Micro Motion recommends:

• Specifying the reference temperature as one of the temperature isotherms

• Selecting a range of temperature values that includes and is slightly larger than the range of expected process temperatures

• Selecting a range of concentration values that includes and is slightly larger than the range of expected process concentrations

Data for many process fluids can be obtained from published tables. Data for sodium chloride is shown in Table 2-4.

Temperature isotherms 1–6

10 Enhanced Density Application: Theory, Configuration, and Use

Enhanced Density Theory and Background continued

Table 2-4 Density of sodium chloride (NaCl) in water (H

Concentration % 0 °C 10 °C 25 °C 40 °C 60 °C 80 °C 100 °C

1 1.00747 1.00707 1.00409 0.99908 0.9900 0.9785 0.9651

2 1.01509 1.01442 1.01112 1.00593 0.9967 0.9852 0.9719

4 1.03038 1.02920 1.02530 1.01977 1.0103 0.9988 0.9855

8 1.06121 1.05907 1.05412 1.04798 1.0381 1.0264 1.0134

12 1.09244 1.08946 1.08365 1.07699 1.0667 1.0549 1.0420

16 1.12419 1.12056 1.11401 1.10688 1.0962 1.0842 1.0713

20 1.15663 1.15254 1.14533 1.13774 1.1268 1.1146 1.1017

24 1.18999 1.18557 1.17776 1.16971 1.1584 1.1463 1.1331

26 1.20709 1.20254 1.19443 1.18614 1.1747 1.1626 1.1492

O) at different temperatures and concentrations

Step 4 Mapping density at reference temperature to concentration

Note: If density at reference temperature or specific gravity was specified as the derived variable, conversion to concentration is not required because these two variables are not measures of concentration. Therefore, this step is omitted.

The enhanced density application must be able to map the density-at-reference-temperature curve to concentration. This is accomplished by:

Theory and Background User-Defined CurvesStandard or Custom CurvesBefore You Begin

• Specifying 2 to 6 concentration values. Micro Motion recommends using the same values that were used in Step 3.

• For each concentration value, specifying the corresponding density of the process fluid at reference temperature.

Again, data for many process fluids can be obtained from published tables. For example, if the process fluid is sodium chloride in water, and the specified reference temperature is 25 °C, the third column of data in Table 2-4 provides the required values.

Step 5 Curve fitting

When data entry is complete, the transmitter automatically generates the enhanced density curve. There are two measures of the goodness of a density curve:

• The outcome of the curve-fitting algorithm. Concentration will be calculated from the input data only if the curve fit results are

Good. If the curve fit results are Poor or Fail, you must

repeat the process with modified data. Options include:

- Correcting inaccurately entered data

- Reconfiguring the curve using fewer temperature isotherms or concentration curves

If the curve fit results are

Empty, the curve-fitting calculation has not completed or has failed.

Wait for another minute, or reenter your data.

• The curve fit error. This value is based on the average error of the curve fit and does not include any error values used to define the density curve, or any error in the density or temperature measurements.

Note: Determination of the overall accuracy of the concentration calculation is complex and can be laborious. If this information is required, contact Micro Motion customer service.

Enhanced Density Application: Theory, Configuration, and Use 11

Enhanced Density Theory and Background continued

The curve fit error is reported in the concentration unit that is currently active. It may be represented as a value like the following:

In this example, if the concentration unit for the density curve is % solids, the average curve fit error is 0.000084337 % solids.

2.5 Enhanced density application example

A plant uses a caustic cleaning solution (NaOH in H To meet emission standards, the total concentration of NaOH in the wastewater cannot exceed 5%. The concentration standard is defined on mass (rather than volume).

Without the enhanced density application

Based on testing, the cleaning solution is assumed to flow into the discharge tank at a concentration of 50%. Therefore, to comply with emission standards, one unit of the cleaning solution should be diluted with 19 units of water. Periodically, samples are tested in the lab to monitor compliance.

This approach has the following drawbacks:

• The concentration of the cleaning solution may be different from the original sample.

• The concentration of the cleaning solution may vary beyond tolerances.

• Laboratory testing is slow and expensive, and may not catch serious variance: some batches may be in violation of standards, while other batches contain more water than required, which is unnecessary expense.

• Processing waste one batch at a time is inefficient.

• There is no provision for handling bad batches.

8.4337E-5

O) and discharges it into the city water system.

With the enhanced density application

A continuous blending process is implemented. A downstream flowmeter with the enhanced density application is configured to measure concentration (mass). Through a PLC, the flowmeter controls an upstream valve that controls the flow of water into the static mixer.

Using this technology:

• Any variation in the concentration of the cleaning solution flowing into the discharge tank is compensated for, immediately and automatically.

• No laboratory testing is required.

• Batching is eliminated, along with bad batches.

12 Enhanced Density Application: Theory, Configuration, and Use

Chapter 3

Loading a Standard or Custom Curve

3.1 About this chapter

This chapter defines standard and custom curves, and provides instructions for loading them.

Note: If the standard curves are not appropriate for your application, you did not purchase custom curves, and you require transmitter output based on enhanced density, you must configure one or more curves to meet your application requirements. See Chapter 4 for instructions.

Note: For information on using and modifying an existing curve, see Chapter 5.

3.2 Standard and custom curves

When the enhanced density application is purchased, a set of six standard curves is supplied. These curves, with the measurement units they are based on, are described in Table 3-1.

These curves are supplied in several different ways:

• For Series 3000 transmitters, if the Food and Beverage Option is purchased, the curves are preloaded into transmitter memory. (The Food and Beverage Option is not available for Series 2000 transmitters.)

Theory and Background User-Defined CurvesStandard or Custom CurvesBefore You Begin

• For Series 2000 transmitters purchased with the enhanced density application, the curves are supplied on the enhanced density CD.

• If ProLink II is purchased, the curves are supplied on the ProLink II installation CD.

In addition, custom curves may be purchased. These curves are defined at the factory using customer-supplied data. Custom curves can be preloaded onto the transmitter at the factory, or the customer can load the curve file(s) into the transmitter.

Table 3-1 Standard curves and associated measurement units

Name Description Density unit Temperature unit

Deg Balling Curve represents percent extract, by mass, in

solution, based on °Balling. For example, if a wort is 10 °Balling and the extract in solution is 100% sucrose, the extract is 10% of the total mass.

Deg Brix Curve represents a hydrometer scale for sucrose

solutions that indicates the percent by mass of sucrose in solution at a given temperature. For example, 40 kg of sucrose mixed with 60 kg of water results in a 40 °Brix solution.

Deg Plato Curve represents percent extract, by mass, in

solution, based on °Plato. For example, if a wort is 10 °Plato and the extract in solution is 100% sucrose, the extract is 10% of the total mass.

g/cm

°F

°C

°F

Enhanced Density Application: Theory, Configuration, and Use 13

Loading a Standard or Custom Curve continued

Table 3-1 Standard curves and associated measurement units (continued)

Name Description Density unit Temperature unit

HFCS 42 Curve represents a hydrometer scale for HFCS 42

(high fructose corn syrup) solutions that indicates the percent by mass of HFCS in solution.

HFCS 55 Curve represents a hydrometer scale for HFCS 55

(high fructose corn syrup) solutions that indicates the percent by mass of HFCS in solution.

HFCS 90 Curve represents a hydrometer scale for HFCS 90

(high fructose corn syrup) solutions that indicates the percent by mass of HFCS in solution.

g/cm

°C

3.3 Loading procedures

If a curve has been provided as a file, it must be loaded into a transmitter slot using ProLink II. See Section 3.3.1. This procedure can be used with any transmitter that can be accessed by ProLink II. It can also be used for any user-defined curve that has been saved to a file.

If a curve has been preloaded into transmitter memory on a Series 3000 transmitter, it must be loaded into a slot using the transmitter display.

• To load a preloaded curve into a slot on the Series 3000 4-wire transmitter, see Section 3.3.2.

• To load a preloaded curve into a slot on the Series 3000 9-wire transmitter, see Section 3.3.3.

If a curve has been preloaded into transmitter memory on a Series 2000 transmitter, it has already been loaded into a slot.

3.3.1 Using ProLink II

Note: This method cannot be used with preloaded curves. The curve must be available as a file.

To load a curve file into a slot using ProLink II:

1. Set the transmitter measurement units for temperature and density to the units used to create the curve you are loading.

• For standard curves, see Table 3-1 for the units to use.

• For custom curves supplied by Micro Motion, see the information provided with the curve.

For information on configuring the measurement units, see your transmitter documentation.

2. Click

ProLink > Configuration > ED Setup. A window similar to Figure 3-1 is displayed.

3. If necessary, change the derived variable. If you are loading a standard curve, set the derived variable to Mass Conc (Dens). If you are loading a custom curve, set the derived variable to the derived variable used by the custom curve. The list of available process variables is updated to match the derived variable.

Warning: Changing the derived variable will erase all existing curve data.

4. Use the loaded (Density Curve 1–6), and click

5. Click the

Curve being configured dropdown list to specify the slot into which the curve will be

Apply.

Load this curve from a file button and specify the curve file to be loaded.

6. Repeat Steps 4 and 5 to load as many curves as required. Make sure that all loaded curves use the same derived variable.

14 Enhanced Density Application: Theory, Configuration, and Use

Loading a Standard or Custom Curve continued

7. If desired, check the Lock/Unlock ED curves checkbox to lock the curves. When curves are locked, no curve parameters can be changed. You can specify a different active curve. You can also specify a different curve to configure, so that you can view the curve parameters, but you cannot change any of those parameters.

Note: The Lock/Unlock ED Curves option is available only on Series 2000 transmitters v4.1 and higher, Series 2000 F

OUNDATION

™

fieldbus transmitters v3.0 and higher, or Series 3000 transmitters

v6.1 and higher.

Figure 3-1 ED Setup window – Loading a curve

Specify the slot (see Step 4) Specify the file to load (see Step 5)

Specify the derived variable (see Step 3)

Theory and Background User-Defined CurvesStandard or Custom CurvesBefore You Begin

Lock the curves (see Step 7)

Enhanced Density Application: Theory, Configuration, and Use 15

Loading a Standard or Custom Curve continued

3.3.2 Using the display on Series 3000 4-wire transmitters

If the Food and Beverage option was purchased, the display can be used to load a standard curve into any slot. To load a standard curve using the display:

1. Open the

Density functions menu (see Figure 3-2). If the derived variable is not Mass conc

(Dens), it will be automatically set to Mass conc (Dens). Changing the derived variable will automatically erase all enhanced density curves in the transmitter. A warning is displayed, allowing you to cancel the action if desired.

2. Select

Load standard curve.

3. Select the slot (Empty curve 1 – 6).

4. Select the curve to be loaded. Any existing data in the selected slot is overwritten.

When loading curves, ensure that the transmitter is connected to the core processor. Curve data is stored in the core processor.

Figure 3-2 Series 3000 4-wire transmitter menu

Configuration

Configure curve

Measurements

Density functions

Load standard curve

Empty curve 1 – 6

Deg Balling Deg Brix Deg Plato HFCS 42 HFCS 55 HFCS 90

16 Enhanced Density Application: Theory, Configuration, and Use

Loading a Standard or Custom Curve continued

3.3.3 Using the display on Series 3000 9-wire transmitters

The display on the Series 3000 9-wire transmitter can be used to load a standard curve into any slot. All curves must be standard or all curves must be custom; you cannot mix standard, custom, and user-defined curves.

To load a standard curve using the display:

1. Using the

Density functions menu (see Figure 3-3), configure the data source from which the

derived variable will be calculated.

2. If the frequency input will be used as the flow source for the enhanced density application, configure the frequency input to represent mass flow. For information on configuring the frequency input, see your transmitter documentation.

3. Using the

Density functions menu:

a. Set the derived variable to Standard.

b. Select the slot (Density curve 1 – 6).

c. Select the curve to be loaded. Any existing data in the selected slot is overwritten.

Figure 3-3 Series 3000 9-wire transmitter menu

Theory and Background User-Defined CurvesStandard or Custom CurvesBefore You Begin

Data sources

Derived variable

Standard

Configuration

Measurements

Density functions

Density curve 1 – 6Configure curve

None Deg Balling Deg Brix Deg Plato HFCS 42 HFCS 55 HFCS 90

Enhanced Density Application: Theory, Configuration, and Use 17

18 Enhanced Density Application: Theory, Configuration, and Use

Chapter 4

Configuring a User-Defined Curve

4.1 About this chapter

This chapter provides information on configuring a user-defined enhanced density curve. Micro Motion recommends that you review Section 2.4 before starting this procedure.

Note: If you are loading a pre-defined curve (a standard or custom curve, or a curve that has been saved to a file), follow the instuctions in Chapter 3.

Note: For information on using and modifying an existing curve, and saving a curve to a file, see Chapter 5.

4.2 Measurement units

When a density curve is configured, the measurement units used to enter temperature and density in the curve data must match the measurement units configured for transmitter processing. If you subsequently change the transmitter’s temperature or density unit, all configured curves will be automatically updated to use the new unit. For information on configuring measurement units, see the transmitter documentation.

4.3 Configuration steps

To configure a user-defined curve using ProLink II, see Section 4.3.1.

To configure a user-defined curve using the Series 3000 display, see Section 4.3.2.

4.3.1 Using ProLink II

Follow the steps in this section to configure a user-defined curve.

Theory and Background User-Defined CurvesStandard or Custom CurvesBefore You Begin

1. Click

2. Specify the derived variable by selecting it from the dropdown list. Derived variables are listed

Note: Changing the derived variable will erase all existing curve data in the transmitter. All curves in the transmitter m ust use the same derived variable. Be sure that any existing curves have been saved to a file before changing the derived variable. See Section 5.5 for information on saving an enhanced density curve to a file.

3. Up to six curves can be configured. Specify the curve to be configured by selecting it from the

Enhanced Density Application: Theory, Configuration, and Use 19

ProLink > Configuration > ED Setup. A window similar to Figure 4-1 is displayed.

and defined in Table 2-1.

dropdown list.

Configuring a User-Defined Curve continued

Figure 4-1 ED Setup window – Configuring a curve

Specify the derived

variable (see Step 2)

Select the curve to configure (see Step 3)

Name the curve (see Step 4a)

Specify reference data (see Step 4b)

Specify extrapolation alarm limit (see Step 4c)

Specify concentration unit label (see Step 4d)

Specify special label (see Step 4d)

Lock the curves (see Step 10)

4. Specify curve setup data:

a. Name the curve as desired. The name can contain a maximum of 8 characters.

b. Specify reference data. Different derived variables require different reference data.

ProLink II enables and disables reference data textboxes as appropriate to your derived variable. Enter data in all textboxes that are enabled, which will include some or all of the following:

• Reference temperature (for the process fluid). Enter the temperature to which the density will be corrected. Enter the temperature value in the temperature units that are currently configured on the transmitter.

• Water reference temperature. Specify the water reference temperature to be used in calculating the specific gravity. Enter a value between 32 °F and 212 °F (0 °C and 100 °C), using the temperature units that are currently configured on the transmitter.

• Water reference density. This value represents the water density as calculated by the transmitter. Modify as required. Enter the value in the density units that are currently configured on the transmitter.

c. Specify the extrapolation alarm limit. This specifies how much the process temperature

and process density can vary above and below the density curve’s defined range before an extrapolation alarm will be posted. For example, if the highest temperature isotherm is 100 °C, and the extrapolation alarm limit is set to 5%, an alarm will be posted if the actual process temperature exceeds 105 °C.

20 Enhanced Density Application: Theory, Configuration, and Use

Configuring a User-Defined Curve continued

Note: As the value for extrapolation alarm limit is increased, the probability of inaccurate enhanced density calculations also increases. Micro Motion recommends using the default value for extrapolation alarm limit.

d. Specify the label to be used for the concentration unit. Pre-defined labels are listed in

Table 4-1. Table 4-1 also describes the typical use of each label. If none of the pre-defined labels is appropriate, select

Special, then enter the text to be used for the label.

Note: The label specified here is used for display purposes, and has no effect on transmitter processing. However, for consistency and ease of use, select a label that appropriately represents the values you will enter in Steps 6 and 7.

e. Click

Apply.

Table 4-1 Concentration unit labels and definitions

Label Typical density curve represents

% Plato Percent extract, by mass, in solution, based on °Plato. For example, if a wort is 10 °Plato and

the extract in solution is 100% sucrose, the extract is 10% of the total mass

% Solids/Mass Percent mass of solute or of material in suspension in the total solution

% Solids/Volume Percent volume of solute or of material in suspension in the total solution, calculated at

reference temperature

degBalling Percent extract, by mass, in solution, based on °Balling. For example, if a wort is 10 °Balling

and the extract in solution is 100% sucrose, the extract is 10% of the total mass

degBaume (H) The conversion for °Baume heavy. The fluid reference temperature is 60 °F and the water

reference temperature is 60 °F. (°Baume is calculated when fluid reference temperature and water reference temperature are both set to 60 °F.)

degBaume 145

This label should be used for fluids heavier than water.

degBaume (L) The conversion for °Baume light. The fluid reference temperature is 60 °F and the water

reference temperature is 60 °F. (°Baume is calculated when fluid reference temperature and water reference temperature are both set to 60 °F.)

degBaume

This label should be used for fluids lighter than water.

degBrix A hydrometer scale for sucrose solutions that indicates the percent by mass of sucrose in

solution at a given temperature. For example, 40 kg of sucrose mixed with 60 kg of water results in a 40 °Brix solution.

degTwaddell A value from which the specific gravity of liquids can be calculated, using the following

formula:

Tx 200 d 1–()×=

where T× is the reading in degrees Twaddell, and d is the required specific gravity

Proof/Mass The proof of the solution, based on mass, and calculated at reference temperature. A value of

50 here is equivalent to a value of 25 using % Solids/Mass.

Proof/Volume The proof of the solution, based on volume, and calculated at reference temperature. A value

of 50 here is equivalent to a value of 25 using % Solids/Volume.

Special Select this option if none of the labels in this table describes your density curve. You will be

allowed to enter a label of your choice.



–=





----------------------------------------------



SpecificGravity

145

----------------------------------------------

SpecificGravity

140

130–=

Theory and Background User-Defined CurvesStandard or Custom CurvesBefore You Begin

5. Click

ProLink > Configuration > ED Curve Config. A window similar to Figure 4-2 is

displayed, showing data for the curve that is currently being configured.

Enhanced Density Application: Theory, Configuration, and Use 21

Configuring a User-Defined Curve continued

This window has two main work areas:

• Process Fluid Density at Specified Temperature and Concentration is used to define the three-dimensional surface described in Section 2.3.2. During the curve-fitting procedure, the enhanced density application will calculate coefficients that will be used to map all points on this surface to their equivalent values at reference temperature.

• Process Fluid Density at Reference Temperature and Specified Concentration is used to enter data that will be used to map density values at reference temperature to the equivalent concentration values.

If you specified Density @ Ref or SG as the derived variable, the Process Fluid Density at Reference Temperature and Specified Concentration work area is disabled, because the derived variable is not a concentration value and therefore this conversion is not required.

Figure 4-2 ED Curve Config window

Concentration curves (see Step 6a)Temperature isotherms (see Step 6b)

Data point textboxes (see Step 6c)

Curve fit results (see Step 8)

22 Enhanced Density Application: Theory, Configuration, and Use

Concentration points (see Step 7a)

Density at reference temperature (see Step 7b)

Configuring a User-Defined Curve continued

6. In the Process Fluid Density at Specified Temperature and Concentration work area:

a. In the

Concentration % textboxes, enter the concentration values that identify the

concentration curves (see Figure 2-6). Enter the values as percentages, in the concentration unit that you want to be used for calculating the derived variable and enhanced density process variables. Minimum number of concentration curves is two; maximum number is five.

Note: If you specified Density @ Ref as the derived variable, enter two to five density values at reference temperature.

b. In the

Temp Iso textboxes, enter the temperature values that define the temperature

isotherms (see Figure 2-6). Minimum number of temperature isotherms is two; maximum number is six.

c. For each data point (intersection of concentration curve and temperature isotherm), enter

the density of the process fluid at the corresponding concentration curve and temperature isotherm. For example, for Point A1, enter the density of the process fluid at concentration A and temperature 1.

Note: You must enter a value for each data point. If any data points are undefined, the curve fitting results will be Empty or Fail.

7. If you specified Density @ Ref or SG as the derived variable, the Process Fluid Density at Reference Temperature at Specified Concentration work area is disabled. Continue with

Step 8.

Theory and Background User-Defined CurvesStandard or Custom CurvesBefore You Begin

If you specified any other derived variable, enter the following in the Process Fluid Density at Reference Temperature at Specified Concentration work area:

a. In the

Concentration % textboxes, enter the concentration points that will define the

curve used to convert density values at reference temperature to concentration values. Enter the values as percentages, in the concentration unit that you want to be used for calculating the derived variable and enhanced density process variables. Minimum number of concentration points is two; maximum number is six. These values may or may not match the concentration curves that you defined in Step 6a.

b. For each concentration point, enter the corresponding density or specific gravity value of

the process fluid at the displayed reference temperature. This is the temperature that you configured in Step 4b.

8. Click

Apply. The transmitter will attempt to fit a density curve to the configured values. The

results of the curve fit algorithm are shown in the

Curve Fit Results textbox. See Section 4.4

for a discussion of curve fitting.

9. Repeat Steps 3 through 8 for as many density curves as required. Note that all density curves must use the same derived variable.

10. If desired, check the

Lock/Unlock ED curves checkbox on the ED Setup window (see

Figure 4-1) to lock the curves. When curves are locked, no curve parameters can be changed. You can specify a different active curve. You can also specify a different curve to configure, so that you can view the curve parameters, but you cannot change any of those parameters.

Note: The Lock/Unlock ED Curves option is available only on Series 2000 transmitters v4.1 and higher, Series 2000 F

OUNDATION

™

fieldbus transmitters v3.0 and higher, or Series 3000 transmitters

v6.1 and higher.

Enhanced Density Application: Theory, Configuration, and Use 23

Configuring a User-Defined Curve continued

4.3.2 Using the display on Series 3000 transmitters

Note: The instructions in this section apply to both 4-wire and 9-wire transmitters.

1. From the

Measurement menu, select Density functions. See Figure 4-3.

2. Specify the derived variable.

3. If you are using a Series 3000 9-wire transmitter:

a. Configure the data source from which the derived variable will be calculated. See

Figure 4-3.

b. If the frequency input will be used as the flow source for the enhanced density application,

configure the frequency input to represent mass flow. For information on configuring the frequency input, see your transmitter documentation.

4. Select

Configure curve.

5. Specify the slot (Density curve 1–6).

6. Use the appropriate flowchart to enter data for your curve.

•For Density at reference temperature and Specific gravity, see Figure 4-4.

• For all other derived variables, see Figure 4-5.

7. When all values are entered, the transmitter will attempt to fit a density curve to the configured values. The results of the curve fit algorithm are shown in the Section 4.4 for a discussion of curve fitting.

Figure 4-3 Density functions menu

Curve Fit Results screen. See

(1)

(1) Series 3000 9-wire transmitters only.

Derived variable

None Density at ref S.G. Mass conc (Dens) Mass conc (SG) Volume conc (Dens) Volume conc ( SG) Conc (Dens) Conc (SG)

Measurements

Density functions

Configure curveDI next curveData sources

24 Enhanced Density Application: Theory, Configuration, and Use

Configuring a User-Defined Curve continued

Figure 4-4 Density functions menu – Density at Ref and S.G.

2Density curve 1 3 4 5 6

Density at ref S.G.

Product name

Other derived variables

See Figure 4-5

Fluid ref. temp Temperature isotherms m Concentration curves n

Temperature 1 Temperature 2 Temperature m

Density at concentration n

Density at concentration 2

Density at concentration 1

• Density at temperature 1

• Density at temperature 2

• Density at temperature m

Curve fit results

Fluid ref. temp Temperature isotherms m Concentration curves n

Temperature 1 Temperature 2 Temperature m

Density at concentration n

Density at concentration 2

Density at concentration 1

• Density at temperature 1

• Density at temperature 2

• Density at temperature m

Water ref temp

Calc. water density

Theory and Background User-Defined CurvesStandard or Custom CurvesBefore You Begin

Curve fit results

Enhanced Density Application: Theory, Configuration, and Use 25

Configuring a User-Defined Curve continued

Figure 4-5 Density functions menu – Mass conc (SG), Volume conc (SG), Conc (SG), Mass conc (Dens),

Volume conc (Dens), Conc (Dens)

2Density curve 1

3 4 5 6

Mass conc (SG)

Volume con c (S G)

Conc (SG)

Product name

Fluid ref. temp Temperature isotherms m Concentration curves n

Temperature 1 Temperature 2 Temperature m

Density at concentration n

Density at concentration 2

Density at concentration 1

• Density at temperature 1

• Density at temperature 2

• Density at temperature m

Mass conc (Dens)

Volume conc (Dens)

Conc (Dens)

Product name

Fluid ref. temp Temperature isotherms m Concentration curves n

Temperature 1 Temperature 2 Temperature m

Density at concentration n

Density at concentration 2

Density at concentration 1

• Density at temperature 1

• Density at temperature 2

• Density at temperature m

Water ref temp

Calc. water density

Number of data points p Output units

SG 1 Concentration point 1 SG 2 Concentration point 2 SG p Concentration point p

Curve fit results

26 Enhanced Density Application: Theory, Configuration, and Use

Number of data points p Output units

Reference density 1 Concentration point 1 Reference density 2 Concentration point 2 Reference density p Concentration point p

Curve fit results

Configuring a User-Defined Curve continued

4.4 Curve fitting

There are two measures of the goodness of a density curve:

• The outcome of the curve-fitting algorithm. The concentration will be calculated from the input data only if the curve fit results are must repeat the process with modified data. Options include:

- Correcting inaccurately entered data

- Reconfiguring the curve using fewer temperature isotherms or concentration curves

Good. If the curve fit results are Poor or Fail, you

If the curve fit results are

Empty, the curve-fitting calculation has not completed or has failed.

Wait for another minute, or reenter your data.

• The curve fit error. This value is based on the average error in the curve fit, and does not include any error in the entered data or any error in the density or temperature measurements.

Note: Determination of the overall accuracy of the concentration calculation is complex and can be laborious. If this information is required, contact Micro Motion customer service.

The curve fit error is reported in the concentration unit that is currently active. It may be represented as a value like the following:

8.4337E-5

In this example, if the concentration unit for the density curve is % solids, the expected curve fit error is 0.000084337 % solids.

Theory and Background User-Defined CurvesStandard or Custom CurvesBefore You Begin

Enhanced Density Application: Theory, Configuration, and Use 27

28 Enhanced Density Application: Theory, Configuration, and Use

Chapter 5

Using an Enhanced Density Curve

5.1 About this chapter

This chapter discusses the following topics:

• Specifying the active curve

• Using enhanced density process variables in transmitter configuration

• Modifying a curve

• Saving a curve to a file

5.2 Specifying the active curve

Only one curve can be active (in use by the transmitter) at a time. Specify the active curve using either ProLink II or the display on a Series 3000 transmitter.

Advanced Options Configuration RecordsRangesUsing Curves

5.2.1 Using ProLink II

To specify the active curve using ProLink II:

1. If the

2. Click

3. Click on

Note: If you are using a Series 3000 transmitter, curves that were loaded through the display are marked with an asterisk (*). This mark does not affect processing in any way.

4. Click Apply.

ED Process Variables window is open, close it.

ProLink > Configuration > ED Setup. The window shown in Figure 5-1 is displayed.

Active Curve. All curves that have been loaded into slots are listed. Select the

desired curve from the list.

Enhanced Density Application: Theory, Configuration, and Use 29

Using an Enhanced Density Curve continued

Figure 5-1 ED Setup window – Specifying the active curve

Specify the active

curve (see Step 3)

5.2.2 Using the display on Series 3000 transmitters

To specify the curve to use for enhanced density calculations using the display on a Series 3000 transmitter, use the

Density curves option in the View menu. See Figure 5-2.

Figure 5-2 View menu – Specifying the active curve

Density curves

Loaded curves

View

30 Enhanced Density Application: Theory, Configuration, and Use

Using an Enhanced Density Curve continued

5.3 Using enhanced density process variables

When the enhanced density application is enabled and an active curve has been specified, any of the available enhanced density process variables can be used like any other process variable. For example:

• Transmitter outputs can be configured to report enhanced density process variables.

• Events can be defined on enhanced density process variables.

• A discrete input can be configured to reset an enhanced density total.

Enhanced density process variables are automatically included in transmitter configuration options.

Note: All “net” process variables assume that the concentration data is based on percent. This includes “net” totals and inventories.

5.4 Modifying the curve

An existing density curve may be modified. The following parameters can be modified without affecting the enhanced density calculations:

• Curve name

• Concentration unit label and optional text string

• Extrapolation alarm limit

Note: As the value for extrapolation alarm limit is increased, the probability of inaccurate enhanced density calculations also increases if the measured density varies beyond the defined density curve. Micro Motion recommends using the default value for extrapolation alarm limit.

Note: Information on performing a density curve trim is provided in Chapter 6.

Do not change any other parameters. In particular, if you change the derived variable, all data is erased for all existing curves.

If you are using ProLink II and the view configuration information for the active curve, but you will not be allowed to make any changes. To make changes, you must first close the

If the density curves have been locked, you will be allowed to change the active curve and to view configuration information for any curve, but you will not be allowed to change any curve parameters.

5.5 Saving a density curve

Micro Motion recommends that all modified or user-defined curves be saved to a file.

Advanced Options Configuration RecordsRangesUsing Curves

ED Process Variables window is open, you will be allowed to

ED Process Variables window.

Note: This feature requires ProLink II and is not available with Series 3000 9-wire transmitters.

To save a curve to a file:

1. Click

2. Use the

3. Click the

ProLink > Configuration > ED Setup.

Curve being configured dropdown list to specify the curve to save, and click Apply.

Save this curve to a file button and specify the file name and location.

4. Repeat these steps for all density curves on your transmitter.

The following are saved to the file:

• Extrapolation alarm limit

• Concentration units label

• Curve trim values

Enhanced Density Application: Theory, Configuration, and Use 31

Using an Enhanced Density Curve continued

The following are not saved to the file:

• Derived variable

• Density and temperature measurement units

Note: Micro Motion recommends keeping a configuration record on paper as well as saving the curve electronically. Configuration record forms are provided in Appendix B.

32 Enhanced Density Application: Theory, Configuration, and Use

Chapter 6

Advanced Options

6.1 About this chapter

This chapter provides information on the following advanced options:

• Curve fit maximum order

• Density curve trim

6.2 Maximum order during curve fit

Curve Fit Max Order defines the maximum order of polynomial to use for the curve fit. The curve

fitting algorithm will always use one fewer than the number of concentration curves used to define the density curve, up to the configured maximum value.

For example, if

• If you enter 3 concentration points, the algorithm will use a second-order polynomial.

• If you enter 4 concentration points, the algorithm will use a third-order polynomial.

• If you enter 5 concentration points, the algorithm will still use a third-order polynomial.

Max Order is set to 3:

Advanced Options Configuration RecordsRangesUsing Curves

Micro Motion recommends leaving

6.3 Density curve trim

Before beginning the density curve trim, click the

Setup

The density curve trim is a field adjustment used to bring the transmitter’s concentration output values closer to reference values over a restricted density and temperature range.

Two modifications can be made to the enhanced density curve: offset only or slope and offset. For most applications, adjusting the offset is sufficient.

6.3.1 Offset trim

To perform an offset trim:

window (see Figure 3-1). This enables the Trim Slope and Trim Offset textboxes.

1. Obtain a good reference value for the concentration of the process fluid. Use the same concentration unit that the enhanced density application is configured to produce (e.g., mass concentration derived from density).

2. Obtain the concentration value calculated by the Micro Motion enhanced density application at the equivalent density and temperature (the measured value).

3. Subtract the reference value from the measured value.

4. (Series 3000 9-wire transmitters only) Divide the value from Step 3 by 100.

5. Enter the result as the trim offset value.

Max Order set to 3.

Show Advanced User Options button on the ED

Enhanced Density Application: Theory, Configuration, and Use 33

Advanced Options continued

Note: Ensure that you use the correct sign: If the reference value is higher than the measured value, enter a positive Trim Offset value; if the reference value is lower than the measured value, enter a negative Trim Offset value.

6. Obtain a new measured value and compare it to the reference value. If it is acceptably close to the reference value, the offset trim is complete. If it is not acceptably close, repeat the trim.

Example

6.3.2 Slope and offset trim

To perform a slope and offset trim:

1. Compare transmitter output to reference values at two points. You will have two reference concentration values and two measured concentration values.

2. Enter both sets of values into the following equation:

Reference concentration, measured in °Brix: 64.21

Transmitter concentration reading, in

Series 3000 9-wire transmitters:

°Brix: 64.93

64.21 64.93– 0.72–=

0.72–

-------------- 0.0072–= 100

Enter a value of –0.0072 for trim offset.

All other transmitters:

64.21 64.93– 0.72–=

Enter a value of –0.72 for trim offset.

Example

ReferenceConcentration A MeasuredConcentration×()B+=

3. Solve for A (slope).

4. Solve for B (offset), using the calculaled slope and one set of values.

5. Enter the results as the trim slope and the trim offset values.

First comparison point:

• Reference concentration: 50.00%

• Measured concentration: 49.98%

Second comparison point:

• Reference concentration: 16.00%

• Measured concentration: 15.99%

Populate equations:

50.00 A 49.98×()B+=

16.00 A 15.99×()B+=

34 Enhanced Density Application: Theory, Configuration, and Use

Advanced Options continued

Solve for A:

50.00 16.00– 34.00=

49.98 15.99– 33.99=

34.00 A 33.99×=

A 1.00029=

Solve for B:

50.00 1.00029 49.98×()B+=

50.00 49.99449 B+=

B 0.00551=

Enter a value of 1.00029 for trim slope.

Enter a value of 0.00551 for trim offset.

Advanced Options Configuration RecordsRangesUsing Curves

Enhanced Density Application: Theory, Configuration, and Use 35

36 Enhanced Density Application: Theory, Configuration, and Use

Appendix A

Isotherm and Concentration Curve Ranges

A.1 About this appendix

This appendix discusses good practices in selecting temperature isotherms and concentration curve values and ranges when defining enhanced density surfaces.

A.2 Fewer versus more points

Sodium hydroxide (NaOH caustic soda) concentration is being measured.

• Under normal operating conditions, the concentration is 20% ± 3%.

• The process is stable at approximately 30°C ± 10 °C.

Table A-1 shows the minimum number of values that must be entered to enable measurement:

Table A-1 Two isotherms and two concentration curves

Isotherms 16% concentration 24% concentration

20.00 °C 1.1751 g/cm

40.00 °C 1.1645 g/cm

This defines the simplest possible surface. For most process fluids, measurement accuracy is improved by adding more concentration and/or temperature values. Table A-2 and Figure A-1 illustrate a density curve that contains density values at two temperature isotherms and three concentration curves.

Table A-2 Two isotherms and three concentration curves

Isotherms 16% concentration 20% concentration 24% concentration

20.00 °C 1.1751 g/cm

40.00 °C 1.1645 g/cm

Advanced Options Configuration RecordsRangesUsing Curves

1.2191 g/cm

1.2079 g/cm

1.2629 g/cm

1.2512 g/cm

1.2629 g/cm

1.2512 g/cm

Enhanced Density Application: Theory, Configuration, and Use 37

Isotherm and Concentration Curve Ranges continued

Figure A-1 Enhanced density surface derived from Table A-2

1.28

Density

in g/cm

1.20

1.10

% Concentration

A.3 Fewer versus more points, and required ranges

Sodium hydroxide (NaOH caustic soda) concentration is being measured.

• The concentration varies from 16% to 50%.

• The temperature varies from 15 °C to 60 °C.

The set of data points used in the previous example are not sufficient here because, for a significant amount of time, the measured density would be outside the defined surface and past the extrapolation alarm limit. Table A-3 shows a set of data points that are chosen to include all expected temperature and concentration values. The resulting enhanced density surface is shown in Figure A-2.

Table A-3 Four isotherms and five concentration curves

16%

Isotherms

15.00 °C 1.1776 g/cm

20.00 °C 1.1751 g/cm

40.00 °C 1.1645 g/cm

60.00 °C 1.1531 g/cm

concentration

24% concentration

1.2658 g/cm

1.2629 g/cm

1.2512 g/cm

1.2388 g/cm

32% concentration

1.3520 g/cm

1.3490 g/cm

1.3362 g/cm

1.3232 g/cm

40% concentration

1.4334 g/cm

1.4300 g/cm

1.4164 g/cm

1.4027 g/cm

Temperature in °C

50% concentration

1.5290 g/cm

1.5253 g/cm

1.5109 g/cm

1.4967 g/cm

Micro Motion recommends selecting a range of temperature and concentration curves that extend past the expected process variation. For example, given the variation described above, you might specify two additional temperature isotherms, one at 10.00 °C and one at 65 °C, and change the concentration curves so that they range from 12% to 55%.

38 Enhanced Density Application: Theory, Configuration, and Use

Isotherm and Concentration Curve Ranges continued

Figure A-2 Enhanced density surface derived from Table A-3

1.6

Density

in g/cm

Advanced Options Configuration RecordsRangesUsing Curves

1.0 16

% Concentration

Temperature in °C

Enhanced Density Application: Theory, Configuration, and Use 39

40 Enhanced Density Application: Theory, Configuration, and Use

Appendix B

Configuration Records

B.1 About this appendix

This appendix provides worksheets or configuration records for each type of enhanced density curve. Make copies as required.

B.2 Electronic versus paper configuration records

Using ProLink II, you can save each enhanced density curve to a file, for backup or copying to other transmitters. Instructions are provided in Chapter 5.

However, the derived variable and the density and temperature units are not saved to the file. Micro Motion recommends using both methods: keeping paper configuration records as well as saving the curve to a file.

B.3 Derived variable: Density at reference temperature

Curve number: __________________________ Curve name: __________________________ Density unit: __________________________ Process fluid reference temperature: __________________________ Extrapolation alarm limit: __________________________ Trim slope: __________________________ Trim offset: __________________________ Concentration units label: __________________________

Temperature

isotherms Reference density values at concentrations A–E

Advanced Options Configuration RecordsRangesUsing Curves



#Value

Enhanced Density Application: Theory, Configuration, and Use 41



C A ______ % B ______ % C ______ % D ______ % E ______ %

Curve number: __________________________ Curve name: __________________________ Density unit: __________________________ Process fluid reference temperature: __________________________ Water reference temperature: __________________________ Water reference density: __________________________ Extrapolation alarm limit: __________________________ Trim slope: __________________________ Trim offset: __________________________ Concentration units label: __________________________

Temperature

isotherms Reference density values at concentrations A–E



#Value



C A ______ % B ______ % C ______ % D ______ % E ______ %

Specific gravity values at concentrations A–F

A ______ % B ______ % C ______ % D ______ % E ______ % F ______ %

48 Enhanced Density Application: Theory, Configuration, and Use

Index

Active curve 29

Concentration

definition 3

Concentration curve 10

recommended ranges 37 Concentration unit label 21 Configuration records 41 Configuring a user-defined curve

using display 24

using ProLink II 19 Curve

configuration records 41

configuring a user-defined curve

using display 24

using ProLink II 19 curve definition overview 7 loading a standard or custom curve 13

using display 16, 17

using ProLink II 14 modifying 31 saving 31 specifying active curve

using display 30

using ProLink II 29 types 1

Curve fit error 11, 27 Curve fit max order 33 Curve fitting 11, 27 Curve trim 33 Custom curves 1

using display 16, 17

using ProLink II 14

Data point 10 Density

definition 3

Density curve

see Curve

Derived variable

available process variables 8 definition 3 in configuring user-defined curves 19 options 8

Enhanced density application

configuration overview 7 configuration records 41 curve fitting 27 example 12

interfaces 1 Enhanced density curve see Curve Enhanced density process variables 31 Extrapolation alarm limit 20

Food and Beverage option 13

Interfaces 1 Isotherm 10

recommended ranges 37

Label

for concentration unit 21 Loading a standard or custom curve

using display 16, 17

using ProLink II 14 Lock/unlock ED curves 15, 23

Max order 33 Measurement units

in configuring user-defined curves 19

in loading standard or custom curves 14 Modifying a curve 31

PPI

see Interfaces Process variables 31

Index

Enhanced Density Application: Theory, Configuration, and Use 49

Index continued

Recommended ranges

concentration curves 37 isotherms 37

Reference density of water

definition 9 in configuring user-defined curves 20

Reference temperature of process fluid

definition 9 in configuring user-defined curves 20

Reference temperature of water

definition 9 in configuring user-defined curves 20

Saving a curve 31 Specific gravity

definition 3

Standard curves 1

description 13 loading

using display 16, 17 using ProLink II 14

Temperature isotherm

see Isotherm Terminology 1 Trim 33

User-defined curves 1

configuring

using display 24 using ProLink II 19

50 Enhanced Density Application: Theory, Configuration, and Use

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Micro Motion Enhanced Density Application Manuals & Guides

Specifications and Main Features

Frequently Asked Questions

User Manual

Contents

Before You Begin

1.1 Purpose of manual

1.2 Terminology

1.3 Transmitter interfaces

1.4 Procedures described in this manual

Enhanced Density Theory and Background

2.1 About this chapter

2.2 Enhanced density application overview

2.3 Measuring density, specific gravity, and concentration

2.3.1 Definition of density, specific gravity, and concentration

2.3.2 Effects of temperature on density, specific gravity, and concentration

2.3.3 Calculating concentration from density

2.4 Defining a Micro Motion enhanced density curve

2.5 Enhanced density application example

Loading a Standard or Custom Curve

3.1 About this chapter

3.2 Standard and custom curves

3.3 Loading procedures

3.3.1 Using ProLink II

3.3.2 Using the display on Series 3000 4-wire transmitters

3.3.3 Using the display on Series 3000 9-wire transmitters

Configuring a User-Defined Curve

4.1 About this chapter

4.2 Measurement units

4.3 Configuration steps

4.3.1 Using ProLink II

4.3.2 Using the display on Series 3000 transmitters

4.4 Curve fitting

Using an Enhanced Density Curve

5.1 About this chapter

5.2 Specifying the active curve

5.2.1 Using ProLink II

5.2.2 Using the display on Series 3000 transmitters

5.3 Using enhanced density process variables

5.4 Modifying the curve

5.5 Saving a density curve

Advanced Options

6.1 About this chapter

6.2 Maximum order during curve fit

6.3 Density curve trim

6.3.1 Offset trim

6.3.2 Slope and offset trim

Isotherm and Concentration Curve Ranges

A.1 About this appendix

A.2 Fewer versus more points

A.3 Fewer versus more points, and required ranges

Configuration Records

B.1 About this appendix

B.2 Electronic versus paper configuration records

B.3 Derived variable: Density at reference temperature

B.4 Derived variable: Specific gravity

B.5 Derived variable: Mass Conc (Dens)

B.6 Derived variable: Mass Conc (SG)

B.7 Derived variable: Volume Conc (Dens)

B.8 Derived variable: Volume Conc (SG)

B.9 Derived variable: Conc (Density)

B.10 Derived variable: Conc (SG)

Index