Scales and Balances with Minimum Weight

Scales and Balances with Minimum Weight
 

SET UP TEST TYPE PACKAGES SCREEN 

The Set Up Test Type Packages screen (shown below) 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.

 

ADDING NEW TEST TYPES 

To add a new Test Type to your database you must first copy the required library file “ScaleBalanceMinWeight.bpl” into the folder labeled “bin” under the ProCalV5 directory (typically “C:\Program Files\Prime Technologies\ProCal V5\bin”) in Windows Explorer. 

 

The “ScaleBalanceMinWeight.bpl” file contains all the information necessary for the Test Type’s automatic and proper setup in ProCalV5. 

 

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 the required file “ScaleBalanceMinWeight.bpl” 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 set points and such when entering calibrations using that Test Type.

 

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 “ScaleBalanceMinWeight.bpl” file must be present in the “bin” directory one level down from the ProCalV5 installation directory. 

 

DEFINITIONS FOR THE SCALES & BALANCES W/MINIMUM WEIGHT TTP 

  • CTL – Calibration Tolerance Limit: This describes the standard limit of passing or failing each section of the test. A measurement or calculation is considered to be failed if it is outside of this limit. 
  • PCTL – Process Calibration Tolerance Limit: This describes an expanded limit of passing or failing each section of the test. A measurement or calculation is considered to be a higher-level failure if it is outside of this limit. 
  • LSDU – Least Significant Digit Unit: This number defines the unit of the CTL and PCTL. For example, if the LSDU is 0.001 g and the CTL is 5 for the Corner Test, the actual limit is +/- 0.005 g.
  • Calibration Code: This A/B/C/D code helps describe the state of the passing/failing of the test. 

 

ENTERING ITEMS USING THE SCALES & BALANCES W/MINIMUM WEIGHT TTP 

When creating a new master record that uses the Scales and Balances Test Type, the Test Type must be applied to the record through the Calibration Points tab on the master record screen. Once a new group has been added to the record, click the Test Type drop-down list and select Scales and Balances from the available Test Types, as shown in the figure below:

 

 

Once the Test Type has been selected, the inputs will change according to the settings defined by the library file. This test verifies the accuracy of a Scale or Balance. The test is configured by specifying the unit of Measurement and Accuracy of the device being tested and setting the Limits for the various tests. 

Collection of calibration data involves 4 tests on the device:

  • Zero Check
  • Repeatability Test
  • Minimum Weight test [the tester has the option of not performing the Minimum Weight test] 
  • Corner (Shift) Check [the tester has the option of not performing the Corner (Shift) Test]. 

 

All tests must pass for the calibration to be considered successful. The Test Type inputs used in this test should be entered through the Group Options box, which can be accessed by clicking the Show Group Options button on the right side of the screen. This interface is shown in the figure below:

 

The inputs are as follows: 

  • Capacity – Capacity value [This is for information only]
  • Corner (Shift) CTL – Decimal value for the CTL for the Corner (Shift) test. Expressed in # of LSDUs. This is a +/- from the Center Reading.
  • Corner (Shift) PCTL – Decimal value for the PCTL for the Corner (Shift) test. Expressed in # of LSDUs.
  • Min Weight Test Required – A drop-down field with options of ‘Yes’ and ‘No’
  • Minimum Weight Factor – Decimal value for the Minimum Weight
  • Repeatability CTL – Decimal value for the CTL for the Repeatability test. Expressed in # of LSDUs. This is the maximum allowable Standard Deviation of the readings
  • Pan Design – A drop-down field with options of ‘Circle’ and ‘Square’
  • Process Tolerance % – Decimal value for the calculating of the Minimum Weight
  • Process Tolerance Res – Decimal value for rounding the Process Tolerance
  • Repeatability PCTL – Decimal value for the PCTL for the Repeatability test Expressed in # of LSDUs.
  • Repeatability Readings – This is the number of readings that will be taken during the Repeatability Test
  • Safety Factor – Decimal value used for calculating the “Smallest Net Sample Weight” Zero Check CTL – Decimal value for the CTL for the Zero Check test. Expressed in # of LSDUs. This is the maximum deviation from zero.
  • Zero Check PCTL – Decimal value for the PCTL for the Zero Check test. Expressed in # of LSDUs. This is the maximum deviation from zero.
  • Zero Check Readings – This is the number of readings that will be taken during the Zero Check Test

 

Field Omissions - All Test Group fields will be eliminated except for Output Resolution and Output Signal Type. All Grid Fields will be eliminated 

 

Field Re-labeling - Output Resolution will be re-labeled ‘LSDU Res’ (LSDU stands for Least Significant Digit Unit. This field value is the number of decimal places used for all measurement readings and the LSDU value.).Plus / Minus field will be relabeled ‘LSDU’. Output Signal Type will be labeled ‘Unit of Meas’. See the figure below. 

Note: The Calculate and Restore Defaults buttons are not accessible and serve no function for the Test Type 

 

ENTERING CALIBRATION RECORDS 

Once a Master record is created that uses the Scales and Balances with Minimum Weight Test Type, the Calibration data can be entered on the Test Results tab of the Calibration record. See figure below:

 

Clicking the View/Enter Data button the Scale/Balance Test Data screen appears. As Found readings may be entered for the Zero Check, Repeatability, and Corner (Shift)

 

The tabbed notebook section of the scales and balances screen containing three (3) different sub-screens or “Pages” available for data entry. These pages are logically grouped on the tabs of the notebook. Each page and its associated fields are described below. To open a page, click its tab with your mouse

 

ZERO CHECK TAB This tab page may be used to enter data for the Zero Check test. In the fields provided you may type the Warm-Up Time (optional), Tare Reading, Weight Applied, As Found, and As Left readings. After entering the data, if you wish to save the record, click the Apply button. Click the Close button to close the screen without saving your changes. 

The Warm-Up time is formatted as follows: HH:MM:SS, where MM < 60:SS < 60 

 

Note: Tare Reading and Weight Applied do not have separate values for As Found and As Left. One value is stored for both As Found and As Left. The As Left Entered check box controls the As Left Entered output value of the related test. When unchecked, the related As Left test entry section of the tab will read “Same as As Found” for all applicable fields. 

You may use the As Found and As Left buttons in the Data View box to view or enter readings for the Trials. 

 

 

REPEATABILITY TAB This tab page may be used to enter data for the Repeatability test. In the fields provided you may enter the Warm-Up Time (optional), Tare Reading, Weight Applied, As Found, and As Left readings. If you selected “Yes” for the Minimum Weight test, there will be two additional fields: 

  • Scales and Balances with Minimum Weight
  • Smallest Net Sample Weight

After entering the data, if you wish to save the record, click the Apply button. Click the Close button to close the screen without saving your changes. 

After entering the readings for the Repeatability test and selecting the Apply button, the Mean, Standard Deviation, Scales and Balances with Minimum Weight and Smallest Net Sample Weight will be displayed. The Calculations are as follows:

  • Mean: ā = (a1 + a2 + a3 + … + an) / n
  • Standard Deviation: Ss = √∑(ai - ā)2 / (n - 1) 

Minimum Weight Calculation 

If Min Weight Test Required is “Yes”, the following calculations are performed using the current test’s Repeatability data: 

 

NOTE: For the sake of this calculation consider the term “Deviation Factor” below to be a temporary variable. The Process Tolerance % will be rounded to the number of decimal places determined by the “Process Tolerance Res” before being used in this calculation.

If Standard Deviation < (0.41 * LSDU): 

Deviation Factor = (0.41 * LSDU); 

otherwise 

Deviation Factor = Standard Deviation; 

[NOTE: In other terms, choose the greater value between the Standard Deviation and (0.41*LSDU)]

  • Scales and Balances with Minimum Weight: ( ([Minimum Weight Factor] * Deviation Factor) / ([Process Tolerance %] / 100 )
  • Smallest Net Sample Weight: [Safety factor] * [Calculated Minimum Weight] . Round result to “LSDU Res” 

The As Left Entered check box controls the As Left Entered output value of the related test. When unchecked, the related As Left test entry section of the tab will read “Same as As Found” for all applicable fields.

 

 

 

CORNER SHIFT TAB 

This tab page may be used to enter data for the Corner (Shift) test or you may select the checkbox Skip Corner Test. If you elect to skip the Corner test you will be required to enter a reason. In the fields provided you may type the Warm-Up Time, Weight Applied, Center Reading, As Found, and As Left readings. After entering the data, if you wish to save the record, click the Apply button. Click the Close button to close the screen without saving your changes. 

After entry of the Center reading, CTL and PCTL High and Low Limit columns (read-only, display-only) will be populated next to each Position reading. 

The Pan Design displays the value select from the Test inputs 

The As Left Entered check box controls the As Left Entered output value of the related test. When unchecked, the related As Left test entry section of the tab will read “Same as As Found” for all applicable fields. 

You may use the As Found and As Left buttons in the Data View box to view or enter readings for the Trials. 

Note: If you enter data onto the Corner (Shift) Tab and then elect to check the Skip Corner Test checkbox, all data will be erased.

 

With Corner Test:

 

Skip Corner Test:

 

PASS/FAIL CRITERIA 

All Tests will have As Left Data record if there is an As Found failure. Pass / Fail criteria is the same for both As Found & As Left 

Zero Check 

All reading within ± (Zero Check CTL * LSDU) (PCTL check also performed on As Found data)

Repeatability Check 

Calculated Standard Deviation Ss ≤ (Repeatability CTL value * LSDU) (PCTL check also performed on As Found calculated Standard Deviation) 

Corner Test 

CTL = Corner (Shift) CTL * LSDU 

(this is to express the CTL as the unit of measure.)

 CTL ≤ (Center Reading – Corner Reading) ≤ CTL (PCTL check also performed on As Found data) 

Any As Found Failure occurs: Group’s As Found Status is set to Failed, otherwise Passed. If Failed, the technician can adjust it. 

Any As Left Failure occurs: Group’s As Left Status is set to Failed, otherwise Passed. 

 

Group Calibration Code 

A = all tests: As Found and As Left passed 

B = any As Found failure (out of CTL), all As Left tests passed 

C = any AS Found failure (out of PCTL), all As Left tests passed. 

D = any As Found failure (out of CTL) + any As Left failure (out of CTL).

 

 
 
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