> For the complete documentation index, see [llms.txt](https://docs.enlyze.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.enlyze.com/en/concepts/downtimes/categories-and-assignment.md).

# Categories & assignment

After a downtime is automatically detected, the question is: **why** was the machine stopped? Assigning reasons to downtimes makes the difference between a mere availability number and a real analysis.

## Downtime categories

ENLYZE distinguishes three categories of downtimes:

### Planned

Planned downtimes are anticipated interruptions that are part of regular operations. Examples:

* Changeovers and product switches
* Planned maintenance
* Cleaning
* Breaks (when configured as planned downtime)

### Unplanned

Unplanned downtimes occur unexpectedly and are typically the biggest levers for improvement. Examples:

* Technical breakdowns
* Material shortages
* Process errors
* Staffing shortages

### No production planned

This category covers periods when no production was scheduled at all. Examples:

* Weekends and public holidays
* Cancelled or unscheduled shifts
* Plant shutdowns

{% hint style="info" %}
Downtimes categorized as "No production planned" are not considered in the OEE calculation. Only downtimes during scheduled production time affect availability.
{% endhint %}

## The downtime catalog

All configured downtime reasons together form the **downtime catalog**. Within the three categories, reasons can be organized into groups, for example by machine section or fault type.

The catalog is the binding selection list for assignment: whoever assigns a reason to a downtime always picks from the catalog. New reasons cannot be created on the spot, and users with the Operator role cannot edit the catalog (see [Roles & permissions](/en/administration/user-management.md#roles-and-permissions)). If a cause is missing from the catalog, the downtime gets an inaccurate reason or none at all. A catalog that is as complete as possible is therefore the prerequisite for a meaningful downtime analysis.

How to build and evolve a complete catalog is described under [Build the downtime catalog](/en/production-optimization/downtimes/defining-reasons.md).

## Assigning reasons

Assigning a reason to each detected downtime is the basis of every downtime analysis. There are different ways to assign downtime reasons:

### Manual assignment

By default, an employee assigns a reason to each downtime in the ENLYZE App. The configured reasons are organized into categories and groups. A downtime can also be split into multiple segments if different reasons apply (e.g. 30 minutes changeover, then 45 minutes breakdown).

### Automation via shift schedules

Shift times can be configured in ENLYZE. Downtimes outside of shift times are automatically classified as "No production planned". This significantly reduces the manual effort.

### Automation via machine signals

Some machines provide information about the reason for a downtime through the controller (fault codes, status messages). These signals can be evaluated via [computed variables](/en/concepts/understanding-machine-data/variables-and-time-series.md#computed-variables) and automatically assigned to the appropriate downtime reasons.

## Why assignment matters

Without assignment, the analysis only shows **that** the machine was stopped and **for how long**. Only with reasons does the following become visible:

* Which downtime causes occur most frequently (Pareto analysis)
* Where the biggest levers for improvement lie
* Whether changeover times are systematically too long
* How the distribution changes over time

{% hint style="info" %}
How to set up the downtime catalog in the ENLYZE App is described under [Build the downtime catalog](/en/production-optimization/downtimes/defining-reasons.md). How to assign reasons is described under [Assign reasons to downtimes](/en/production-optimization/downtimes/assigning-reasons.md).
{% endhint %}

## Related topics

* [Detection](/en/concepts/downtimes/detection.md): How downtimes are automatically detected.
* [Availability](/en/concepts/understanding-oee/availability.md): How downtimes affect OEE.
* [6 Big Losses](/en/concepts/understanding-oee/6-big-losses.md): Downtimes in the context of the six major loss sources.