> 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/resources/data-infrastructure/data-sources.md).

# Data sources

A **data source** is a device or system that ENLYZE connects to via a connector to make its data accessible. From the connected data sources, ENLYZE extracts the data, prepares it, models it, and harmonizes it.

ENLYZE distinguishes two kinds of data sources:

* **OT data sources** are devices on the shop floor, such as controllers (PLCs), sensors, or energy meters. From these, ENLYZE receives time-series and process data. Which OT data sources are supported and how they are connected is covered under [OT connectivity](/en/connect/ot-connectivity.md).
* **IT data sources** are IT systems, such as ERP, MES, or QMS systems. From these, ENLYZE typically receives the production context (production run, product, scrap, etc.). How IT systems are connected and read out is covered under [IT connectivity](/en/connect/it-connectivity.md).

Currently, only **OT data sources** are shown in the app: they are modeled in ENLYZE and connected through connectors so you can understand where which data comes from. **IT systems** are connected and read out by ENLYZE via individual ETL (Extract, Transform, Load) jobs and do not appear explicitly in the app.

{% hint style="info" %}
ENLYZE can generally also write data back to connected systems.
{% endhint %}

## Data sources in the platform

In the data sources overview you see all data sources across all machines, organized by site and machine, with connector type and connection status.

<figure><img src="/files/jPjLcJaUj3u6tKyjhfBF" alt="The data sources overview in the Platform area as a table"><figcaption><p>The data sources overview with site, machine, host, connector, last readout, and edge device.</p></figcaption></figure>

The detail view of a data source shows the manufacturer and device model, the connection details, the assigned connector and [edge device](/en/resources/data-infrastructure/edge-devices.md), and the status of the last readout including any errors.

[**Open in the app**](https://app.enlyze.com/platform/data-sources)

## Variables

A **variable** is a concrete data point that ENLYZE reads from a data source, for example a temperature, a speed, or a counter value. A data source typically provides several variables, of which you record the relevant ones.

Recorded variables are given a display name, a unit, and, if needed, a scaling factor in ENLYZE, and are then available in near real time and historically.

## Relationships

* A data source belongs to exactly one [machine](/en/resources/production-hierarchy/machines.md).
* OT data sources are connected through an [edge device](/en/resources/data-infrastructure/edge-devices.md).
* OT data sources deliver one or more variables.

## Connecting data sources

How to connect data sources technically is explained in the [OT connectivity](/en/connect/ot-connectivity.md) and [IT connectivity](/en/connect/it-connectivity.md) sections.