Physical Quantities and Calculation Formulas


When you are Configuring a Calculated Point, use the Configure Units, Quantities, and Formulas dialog to help choose the calculation required by the point.

To Add/Edit New Quantities or Calculation Formulas

  1. There are a few ways to access the Configure Units, Quantities and Formulas dialog.
    1. Via Create Point or Rename Point (both are accessible from the Digital Twin Explorer treeview context menu)
    2. Via Configure Point – an option on the Digital Twin Explorer treeview context menu and the Digital Twin Explorer Selection Tool menu. Click the button to open the dialog.
  2. The most common way to access would be, as you Build the Structure, you will reach the Create Point dialog. From the Choose Point Type drop-down, select the Calculated Point option.
  3. Expand the Point Units drop-down and choose from the available options.
  4. To the right of the Point Units field is an icon, click it.
  5. On the Configure Units, Quantities, and Formulas dialog review the existing units. If none are suitable, click the Add button to create a new unit or formula.
    • The Physical Quantities tab presents all units currently in the database. Adding a new unit will include it in the database, making it available for future use.
    • By choosing from the Units table, you attach meaning to a Point and its data. The current master set is shown below with the added Physical Quantity.
      Units Physical Quantity Description
      Mpy Velocity mils per year
      Mmpy Velocity millimetres per year
      Mils Length thousandth of an inch
      Mm Length millimetre
      Litres Volume litres
      V Electrical Voltage voltage, power / current
      °C Temperature degrees centigrade
      °F Temperature degrees Fahrenheit
      m/s Velocity metres per second
      pH pH potential of hydrogen
      Ppm Concentration parts per million
      Ppb Concentration parts-per-billion, 10−9
      gm/barrel Concentration grams per barrel
      Gms Mass grams
      Bar Pressure  
      ft/s Velocity feet per second
      Psi Pressure pounds per square inch
      Amps Electrical Current amperes
      mA Electrical Current milli-amperes
      USGPM Volumetric Flow Rate US gallons per minute
      Gallons Volume gallons
      IBCs Volume intermediate bulk containers
      Drums Volume drums
    • This list shows all available Units in the system. You may select or type in a Physical Quantity to associate with the Units.
    • The Calculation Formulas tab presents all Formulas currently in the database. Adding a new Formula will include it in the database, making it available for future use.
    • Left-Click in a cell to edit the Formula or the Name.
    • Enter a name for the formula, the formula string, and assign it to a physical quantity.
  6. After editing the Physical Quantities and Calculation Formulas, save and close the dialog.
  7. Select the required units for the calculation point from the Point Units drop-down. This will in turn, link the calculation point to any formulas with Physical Quantities that match the calculation point unit’s Physical Quantities. The matching formulas will appear in the Formula Helper drop-down within Calculation Designer.

Deleting Physical Quantities and Calculation Formulas

On the Configure Units, Quantities, and Formulas dialog, review the existing options. Choose the unit or formula that you wish to eliminate then click the Delete button.
Note: Deleting a Units and Physical Quantities row from the dialog will only delete the link between the units and the physical quantity. It will not delete the units or the physical quantity, which will remain available from the drop-down.
Note: Deleting a Calculation Formulas row from the dialog will delete the name and the formula from the system. It will not delete the physical quantity, which will remain available from the drop-down.