Define Derived Parameter

Derived parameters provides the option to define the parameters using expressions based on the use case scenarios.

Perform the following steps to define derived parameters:

  1. Click Parameter > Derived tab.

    When adding a record for any parameter under the Parameter section (Constructional, Operational, Derived, Predicted, or Physical Property), if a parameter is already associated with any of these categories, it does not appear in the add record parameter list. For example, if you add a record for a Constructional parameter, the same parameter is not available for selection in Constructional or any other listed categories.

  2. Click Add Record button.

  3. Select the Derived parameters required for this system template by selecting the check box next to them.

    You can also search the required parameters using the search box in the top right corner of the window.

  4. Click Add.

  5. In Derived tab after adding the parameter, click Define button in the Formula column. Expression Builder window opens.

    APM application enables you to define derived parameters by providing mathematical expression based on constructional, operational or other derived parameters of the same template. You can define derived parameters using mathematical expression at system template level. When you instantiate the template and create specific equipment instance, you can specify further details for the derived parameter calculation such as calculation frequency, OT tags to be used for calculation etc.

  6. Enter the details to define the derived parameter. Following table provides description of the fields and options in Expression Builder window.

    Field

    Description/Action

    Name

    Enter a unique name for the Expression.

    Description

    Enter short description of the Expression.

    Keyword

    Enter a Keyword.

    Expression

    Define an expression/formula to derive the parameter from other parameters and functions.

    Functions

    1. Click the tab to view the options. Various functions are grouped under three categories, namely Trigonometry, Logarithmic, Mathematical and Aggregation.

    2. Click a category to view the functions under them.

    3. Click a function to use it in the expression. The function appears in the Expression field.

      You can also use the search box on the top of the tab to search a function to use it in a expression.

    Parameters

    1. Click the tab to view the options. All the parameters are grouped under five categories, namely Constructional, Operational, Derived, Predicted and Reference.

    2. Click a category to view the parameters under them.

    3. Click a parameter you want to use it in the expression. Select the nature of the parameter from the options displayed. The function appears in the Expression field.

      You can also use the search box on the top of the tab to search a Parameters to use it in a expression.

    Operators

    1. Click the tab to view the options.

    2. Click Mathematical, Comparison, Logical and Conditional to view the Operators under them.

    3. Click an Operator to use it in the expression. The Operator appears in the Expression field.

      You can also use the search box on the top of the tab to search an Operator to use it in a expression.

    Constants

    1. Click the tab to view the available constants.

    2. Click a Constant to use it in the expression. The Constant appears in the Expression field.

      You can also use the search box on the top of the tab to search a constant to use it in a expression.

    For more information about the Functions and Operators and Expression Grammar see Calculation Engine.

  1. Click Validate button to validate the Expression created. "Successfully validated" message appears at the bottom of the window.

  2. Click Save.

You must define expressions for all the derived parameters before submitting for review or approval.