> For the complete documentation index, see [llms.txt](https://docs.videc.de/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.videc.de/acron-9.3/en/anlagenkonfiguration/verfahrensgroessen/kennzahl.md).

# Key figure

The basic structure of a key figure corresponds to that of a standard calculation variable.

A key figure is created on the basis of the selected [key figure template](/acron-9.3/en/anlagenkonfiguration/kennzahlvorlagen.md). This template assigns default values to all required properties of the key figure.

[Process variables or fixed values](/acron-9.3/en/anlagenkonfiguration/verfahrensgroessen/kennzahl/register_formel.md) must be assigned to the individual formula parameters.

When allocating the process variables, a validation process ensures that only process variables with units originating from the template category are offered for selection.

<details>

<summary></summary>

The template unit is kg/m³. When creating the key figure, the variable allocation function offers only process variables with units of the Mass/Volume category, such as mg/l, g/l, kg/m³, etc.

</details>

Key figure units are converted automatically.

All other settings can be changed as required, except for the formula and the unit categories.

Note

The key figure templates are set up so that the formulas are as far as possible generally applicable. The various key figures are obtained by appropriate allocation of the matching process variables. There is a template for daily polluting loads for example. The individual key figures for COD, BOD5, total nitrogen etc. are obtained by allocating the relevant process variable to the parameter for the substance concentration.


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