Creating Equations

Use

When you prepare industry-relevant compliance requirements at your company, you can identify regulatory equations that must be used for the calculation of the environmental data (for example, calculation of produced emissions). Either you can identify these equations in the regulations, permits, policies, or depending on the business case, you can specify equations of your own in the compliance requirements. The equations control the mechanism of identification and calculation of environmentally-relevant data at the company, and later on, the reporting of this data to the authority or the supervisory organization.

At this stage, you can enter the equations in the compliance requirement paragraphs and pre-define their future use in compliance scenarios by specifying some additional details. An equation definition consists of a result and a mathematical expression. The result of the equation stands for the environmentally-relevant data that is the focus of the compliance requirement. When you define equations, you can specify the following types of results:

Final

The final results represent the final values that are the product of the calculations. You can use final results for direct reporting to the authorities. Depending on the use case, you can also use final results in other expressions of the same equation (similarly to the intermediate results).
Intermediate

The intermediate results represent transitional values that are used (for example, as input variables) in other expressions of the same equation. You cannot use intermediate results for direct reporting of data to the authorities. Instead, you can specify various expressions with intermediate results that can be reused in the equation for calculating environmental data. This way, the expressions with intermediate results facilitate the definition of larger, error-prone equations. Using expressions with intermediate results in the equation, you can fragment the larger expressions semantically (grouping similar expression fragments by function, for example data aggregations), or by nature (for example, CO₂-related or NO_X-related expression fragments) and reuse them within other expressions.

The mathematical expression of an equation consists of numbers (constants), mathematical functions, operators, and input variables that are used in the calculations. Note that you can reuse the intermediate or final results (output variables) as input variables within the expressions of the equation. However, to avoid recursive references between expressions, there are sequence dependencies and restrictions that are implemented in the Check Consistency functionality. Additionally, to ensure the correctness of the entered dimensions, you can use the Check Dimensions functionality.

The equations conform to the lifecycle of the compliance requirement. When the requirement is released, the equation is also released for active usage.

For more information, see: Editing Compliance Requirements.

Prerequisites

You have prepared the environment management master data in the system. Depending on the equation that you wish to create, you must have created one of the following: chemicals (mixtures or listed substances) or physical parameters.

For more information about environmental management master data, see: Preparing Locations and Chemical Data for Environment Management.
You have specified chemical properties in Customizing for SAP EHS Management Environment Management Master Data Configuration Specify Chemical Properties.
You have specified units of measurement in transaction CUNI.

Procedure

To create a new equation, choose Add.
Enter a name and description of the equation.
In the Results section, proceed as follows:
1. To create a new equation with a given result, choose Add.
2. In the Result drop down menu, enter the type of the result, Final or Intermediate.
3. In the Output Variable Name, enter the name of the result.
  
  The output variable name that you enter is a reference to the result of the created expression. Anytime, when you create other expressions in the same equation, you can use the output variables of the expressions as input variable for the newly created expressions.
4. Enter information in the other, optional fields if needed.
  
  Note
  The information that you provide about the data period, the subject of the result (a chemical or a physical parameter), and the unit construct the title of the result. The title of the final result is essential for specifying the environmental data that is produced by the calculation. However, this information is optional for the creation of the equation. If you do not specify this information at this stage, you will have to specify it later on when you create calculation based on this equation.
5. Choose OK.
Enter an expression and optionally a description for each of the newly created results.

For more information about the operators and functions that you can use in the expression, see: Calculation Operators and Functions.
In the Input Variables section, specify the variables in the provided expressions (intermediate or final).
1. You can add the input variables from the expressions manually, using the Add button. Otherwise, you can use the functionality that scans the expressions and adds all potential variables.
2. Enter the name and optionally the description of the added variable.
3. In the Expected Data Source sub-section, enter the information that is required.
  
  You can specify what data is expected for the input variable when the equation is used productively in calculations.
  Caution
  - At this stage, the expected environmental data that you specify in this section is optional. However later on, when you create calculations using the equation, the specified environmental data becomes a prerequisite for the input variables of the calculation. Later on, the application does not mark the fields as mandatory but there is a functional check that prevents the assignment of data that differs from the data specified at this step.
  - If you specify expected data source which data period differs from the data period of the result, you have to aggregate the data periods that are smaller than the data period of the result. You can do that by using aggregation functions in the expression.
Save your entries.

At this point, you only define the equations as a basis for future calculations. Later on, you can map real data to these equations and perform calculations of environmentally-relevant data.

For more information about using predefined equations, see the section Creating Calculations with Predefined Equations of the following procedure: Creating Calculations.