# Test Groups Configuration

A *test group* is a logical container which groups one or more DUT's together with one or more power supplies and temperature sensors. You need to define at least one test group.

![Groups](https://1704635928-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FH5etzy4TvPRLxLRNfHlb%2Fuploads%2Fgit-blob-a2904c61a0bb638f70afbe1166f17d56bc4d378f%2FDLG_PW_Groups.png?alt=media)

To **add a test group** simply click on an empty row in the grid and type a name. To **delete a test group** select a row and press the DEL key on your keyboard.

The **Max. Runtime** parameter is the desired runtime in hours of the tests running under this group. You can later change this parameter in the [F10 - test parameter configuration](https://docs.irs.systems/ltt/documentation/ltt-gui-manual/lttgui/dialogs/f10testparameterconfiguration) dialog.

The **TCC mask** determines, which of the total of 8 [TCC inputs](https://docs.irs.systems/ltt/documentation/ltt-gui-manual/lttgui/hwcontrol/tcc-control-gui) you want to use for this group. You can use all 8 inputs or just a subset of them. You can also use the same inputs in multiple groups. The TCC mask determines, which TCC indicators are displayed for each group in main window's [group display](https://docs.irs.systems/ltt/documentation/ltt-gui-manual/lttgui/mainwindow/groupdisplay) or in the [F10 - test parameter configuration](https://docs.irs.systems/ltt/documentation/ltt-gui-manual/lttgui/dialogs/f10testparameterconfiguration) dialog.

{% hint style="info" %}
If you move your mouse cursor over such an TCC input indicator, a tooltip appears, showing the TCC indicator index. The index goes from 1 to 8 (left to right).
{% endhint %}

Finally you assign one or more of the **available power supplies (PS) and temperature sensors (TS)** to each group. Those are defined in the [module configuration file](https://docs.irs.systems/ltt/documentation/ltt-gui-manual/configuration/moduleconfiguration), which you need [setup](https://docs.irs.systems/ltt/documentation/ltt-gui-manual/gettingstarted/initial-setup-guide) before running the project wizard. Multiple power supplies and temperature sensors are differentiated by a 1-based index following its fixed prefix (PS or TS). In TestStand you can [refer to those power supplies and temperature sensors](https://docs.irs.systems/ltt/documentation/teststand/predefinedvariables#PS_TS_INDEX) by using that index.

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[go to initial setup guide](https://docs.irs.systems/ltt/documentation/gettingstarted/initial-setup-guide#SETUP_GUIDE)