Uncertainty Test Type

Uncertainty Test Type
 

Section 1

 

1.1 Test Types

Our Uncertainty Test Type add-on modules are available to assist you in your calculation of measurement uncertainty budgets for the use in uncertainty statements. As you read through this manual, you may note the flexible power and ease-of-use of our Uncertainty Budget Calculation and Document Uncertainty Component packages. Whether you are looking for a quick summary of combined uncertainty or are planning to integrate known UUT or standard uncertainties with field-discovered uncertainty contributors, the Uncertainty Test Type Packages will allow you to document uncertainty electronically on your calibration history records in ProCalV5

 

1.2 Set Up Test Type Packages Screen

The Set Up Test Type Packages screen (shown in Figure 1) is used to add, modify and if necessary delete test type packages from the database.   This screen is invoked by selecting the “Set Up Test Type Packages…” option on the File menu when the System Options and Defaults screen is open.

 

                                                                                                                                                                                    Figure 1
 

 1.3 Adding New Test Types

To add a new test type to your database you must first copy the required library file(s) “*.bpl” into the folder labeled “bin” under the ProCalV5 directory (typically “C:\Program Files\Prime Technologies\ProCal V5\bin”) in Windows Explorer, or by using a supplied installation package.  The “.bpl” file contains all the information necessary for the test type’s automatic and proper setup in ProCal.  Once the file has been copied into the correct folder you may launch the Set Up Test Type Packages screen.  Once the screen is open you may click the Add New Record button or select “New Record” from the screen’s File menu.  This will invoke a browser screen titled Choose New Package File that automatically directs you to the “bin” folder in which all the “.bpl” files reside. Select one of the “.bpl” files and click the Open button or double-click the file name.

 

Once the correct file has been selected you will be returned to the new test type record which will already be set up for you.  In this instance you can save the record, making it available for application to all types of item master records in the system (i.e. instruments, loops, systems, test instruments, in addition to any PM records that may require a calibration).   Once a test type has been saved to the database, as long as it is marked as “Active”, it will be available for selection on the Test Type field’s drop-down list on the Calibration Points tab in all screens where that tab exists.  

 

Although you will have no ability to change the test type’s calibration requirements, you do have the ability to make some customizations to it in terms of field label changes and also giving users the ability to edit target setpoints and when entering calibrations using that test type.  Please reference section 8 of the ProCalV5 User Manual for information on modifying test type packages once they have been imported into the database.

 

1.4 Distributing Test Types

Test Types only need to be installed in the System Option and Defaults screen once, but for all Client, Administrator, or Mobile Workstations, the “bpl” file must be present in the “bin” directory one level down from the ProCalV5 installation directory.

Again, this may be accomplished manually using Windows Explorer or batch file scripts, or by using a supplied installation package.

In general, the process is:

  1. Install the package(s) on the first workstation.
  2. Use the System Options and Defaults screen’s File menu item for set up test type packages. Add a new package and select the .bpl for the new package. Save the package.
    1. For this package, this process must be done twice. Once for “UncCalc1.bpl” and once for “UncComp1.bpl”.
  3. For all other workstations, simply install the package(s) on each workstation, without registering them with the database.

1.5 Configuration Relevant to Uncertainty Test Types

On the Additional Inputs tab, the user can configure the Restrict Editing checkbox for the various Test Type Inputs. (See Figure 2 below) When these boxes are checked, users cannot change the input values during Calibration Entry. When unchecked, users may make modifications to values.

These values include:

  • On Uncertainty Budget Calculation Test Type:
    1. Coverage Factor (k)
    2. Num of Sig Figures
  • On Document Uncertainty Component Test Type:
    1. Distribution
    2. Uncertainty Value

 

Since these Test Input values may impact the resulting calculations of Uncertainty values during Calibration, you may consider checking these Restrict Editing checkboxes here, so that users cannot modify the values from their defaults given on the Master Record.

                                                                                                                                                                                  Figure 2

Section 2

2.1 Introduction

The Uncertainty Budget Calculation Test Type Package for ProCalV5 allows the user to calculate an Expanded Uncertainty value for a given engineering unit and Coverage Factor (k), expressed in the desired number of significant figures. The user can manipulate component values, add components or remove components from the list of values that are used to calculate the Uncertainty. These values can then be displayed on customized reports or viewed in the electronic record.

 

2.2 Master Record Setup

On the Master Instrument Record Screen, (or any other calibrated master record screen such as Loop, System, or Test Instrument, or a Calibration PM item) under the Calibration Points tab, a test type package can be assigned to the Master Instrument Record through the Test Type pull down menu.

 

In Figure 3 below, the gauge under test is given a pre-determined specification for its Uncertainty Budget Calculation. Note that other test groups can be used on the same calibration for the typical accuracy or repeatability tests.

 

                                                                                                                                                                                  Figure 3

To allow Uncertainty Budget calculations on a master record:

 

  1. Create a new Test Point Group for this item.
  2. On the new Test Point Group, assign a Group Name (optional) and choose “Uncertainty Budget Calculation” on the Test Type field. Hit the TAB key or select another field. You will notice that the test point grid and certain fields are removed from the screen. This is because they are not applicable to this portion of the test.
  3. Choose a Unit. This is the unit that is used in expressing the uncertainty. For automatic uncertainty component linking, this Unit must match the Unit selected on the Document Uncertainty Component groups for the Test Instrument or other test group. See section 5 for more information on component linking for uncertainty calculations.
  4. Optionally, enter a range for this unit.
  5. Click the Show Group Options button to bring up the Additional Test Type Inputs grid.
  6. Choose a Coverage Factor (k) from the drop down list and enter the Number of Significant Figures (Num of Sig Figures) you want the final Uncertainty value rounded to.
  7. Save the record. Now, the Test Type for calculating an uncertainty budget is assign to this record.

 

Usage of the Uncertainty Budget Calculation Test Type is done during entry of a Calibration record.

 

2.3 Calibration Record Entry and Calculation

When a Calibration for an item that uses the Uncertainty Test Type is entered, the Uncertainty calculation appears as a test point group to have data entered into it during Calibration. The Test Results tab will display the test point group created to use this test type.

 

When displaying a test group using this package, the test point grid is removed and the Test Type Inputs and Test Type Outputs grids are displayed, as shown in Figure 4. Test Type inputs are populated with data set up on the Master Record. Depending upon your configuration (See Section 2), you may be able to edit the data in this grid to use different values for this calibration record. The Coverage Factor and Num of Sig Figures grids are important later in this section when using the pop-up Uncertainty Budget window.

 

After entering other calibration data and choosing your test standards, click the View/Calculate button to start the calculation of your Uncertainty Budget.

 

                                                                                                                                                                                  Figure 4

 

On the pop-up Uncertainty Budget screen, (Figure 5 below) the user can enter uncertainties discovered during calibration and apply them to the current list for Uncertainty computation. The user may also want to remove a default uncertainty component or reinitialize the list from an updated list of Test Instruments used (assigned on the Calibration record) and other test groups (See Section 5 for more information on automatic linking of Uncertainty components).

                                                                                                                                                                                  Figure 5

2.4 Uncertainty Calculations

Standard Uncertainty = Round (Num of Sig Figures- (LOG10 (Uncertainty/divisor)))

Standard Uncertainty

Std unc = RND(s-(Log10(U(i)/d)))                              

Where     s = Num of significant figures

Ui = Uncertainty value

d = Divisor

________________________________________________________________

Combined Standard Uncertainty = Round (Num of Sig Figures- (LOG10(SQRT(SUMSQ(Standard Uncertainty))))

Combined Standard Uncertainty

                                                                                                                                           2

Combined std unc = rnd(s-(Log10(√ std unc)   )

________________________________________________________________

Expanded Uncertainty = Round (Num of Sig Figures- (LOG10(Combined std unc * C)))

Expanded Uncertainty

Expanded unc = rnd(s-(Log10(Combinedstd unc) * C)

Where     C = Coverage Factor

________________________________________________________________

Expanded Uncertainty Rounded up = Round (Num of Sig Figures- 1-(LOG10(Expanded unc)))

Expanded Uncertainty Rounded up

Expanded unc = rndup(s-1-(Log10(Expanded unc)))

To begin calculating uncertainties on the pop up Uncertainty Budget screen, the user must click the “Add Component” button, unlocking or creating modifiable grid columns under the Component Description, Uncertainty U(x), and Distribution fields.  

The user can then enter data into these grid columns, and the data entered into Uncertainty U(x) is calculated with the divisor associated with the chosen distribution for that particular Uncertainty Component, and the Standard Uncertainty for that component is displayed according to the calculation. The Divisor and Standard Uncertainty grids are not modifiable, as they are contingent on the data entered in the other grids. Click the “Apply” button to save changes.

The result of the calculation of multiple different uncertainty components is shown in the read-only Combined Standard Uncertainty field. Notice in figure 6 below, that this field changes with the addition of new components.

 

 

                                                                                                                                                                                  Figure 6

The coverage factor is used as a multiplier of the Combined Standard Uncertainty in order to obtain the Expanded Uncertainty, as seen in Figure 7 below. The Expanded Uncertainty is automatically calculated using the RSS (root sum square) method against the list of Standard Uncertainty values as they are entered. The Coverage Factor and the number of significant figures used to round the Expanded Uncertainty are drawn from the Test Type Input grids on the Test Results tab.

 

                                                                                                                                                                                  Figure 7

A component can be deleted by clicking the “Remove Component” Button. Note that when a component is removed, the data entered for that component becomes the default for any new added components until the pop up Uncertainty Budget screen is closed by clicking the “Close” Button. Removed components can also be restored by clicking the “Reset” Button.

 

For information on the functionality of the “Reinitialize Data” button, see section five on Uncertainty Linking.

 Section 3

3.1 Documenting Uncertainty Components

Master records may use the Document Uncertainty Component TTP (test type package) to specify an uncertainty component. This TTP permits the user to use an Engineering Unit, an Uncertainty Value, and a Distribution for a single component. Multiple test groups can be defined to further define multiple uncertainty components for a single item.

3.2 Master Record Setup

On any Master Record screen, under the Calibration Points tab, the “Document Uncertainty Component” test type package can be assigned to the Master Instrument Record through the Test Type pull down menu.

Figure 8 below shows a Test Instrument used as a reference gauge that has a Document Uncertainty Component group for documenting the uncertainty related to its own readability.

 

                                                                                                                                                                                  Figure 8

To document a component of uncertainty on a master record:

 

  1. Create a new Test Point Group for this item.
  2. On the new Test Point Group, assign a Group Name (optional) and choose “Document Uncertainty Component” on the Test Type field. Hit the TAB key or select another field. You will notice that the test point grid and certain fields are removed from the screen. This is because they are not applicable to this portion of the test.
  3. Fill in a value for the Uncertainty Value Description. This is used during component linking for the Component Description field on the Uncertainty Budget screen when Uncertainty Budgets are calculated.
  4. Choose a Unit. This is the unit that is used in expressing the uncertainty. For automatic uncertainty component linking, this Unit must match the Unit selected on the Uncertainty Budget Calculation group for another group on this item, or for the items that this Test Instrument is used for during calibration. See section 5 for more information on component linking for uncertainty calculations.
  5. Optionally, enter a range for this unit.
  6. Click the Show Group Options button to bring up the Additional Test Type Inputs grid.
  7. Choose a Distribution from the drop down list and enter the Uncertainty Value.
  8. Save the record.

3.3 Calibration Record Entry

When a Calibration for an item that uses the Document Uncertainty Component test type package is entered, the test point group with this data appears as any other test group. For the most part this data is just for reference here.

 

Important Notes:

  • There is no data entry required for this group, as it does not factor into the Pass/Fail determination of the calibration record.
  • Depending on the Test Type Package configuration, the user may be able to edit the data in the Test Type Inputs grid that appears on the Calibration screen. This does NOT affect Master Record data, but may affect the Uncertainty Budget Calculation Test Type, if it is attached to the same calibrated item.

 

Section 4

4.1 Uncertainty Linking

The Uncertainty Budget Calculation Test Type has the ability to automatically load uncertainty components for matching Units from two sources:

 

  1. Test Point Groups on Test Instruments assigned to the Calibration record.
  2. Other Test Point Groups on the master record undergoing calibration

If you have documented an Uncertainty Component of a particular unit on an Instrument, and you perform an Uncertainty Budget Calculation of this same unit on that same Instrument, that component (or multiple components if multiple groups are used) is automatically pulled in as a component of uncertainty during calculation.

4.2 Uncertainty Budget Calculation with Automatic Linking

When an item is calibrated and one Test Point Group on this item includes the Uncertainty Budget Calculation TTP, if the user has assigned the appropriate standards this test group will automatically bring in all uncertainty components of these standards by default. The package will also auto-load any other uncertainty components defined for the item under test.

By clicking the “View/Calculate” button on the Calibration screen, the user can also manipulate component values, add components or remove components from the list. These values can then be displayed on customized reports or viewed in the electronic record.

The user may also want to remove a default uncertainty component or Reinitialize the list from an updated list of Test Instruments used (assigned on the Calibration record) and other test groups.

Furthermore, the user may choose to Add or Remove components of Uncertainty as they wish.

If they would like to reset to the current set of test point groups or test standards associated with the current Calibration record, they may choose the Reinitialize Data button.

 

WARNING: Clicking “Reinitialize Data” will cause any Uncertainty components you’ve entered to be removed from the grid. The Uncertainty Budget Screen will warn you if you choose to use this function.

 
 
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