# Predefined Variables

URL: https://irs.systems/en/docs/ltt/documentation/ltt-gui-manual/teststand/predefinedvariables

There are certain variable structures in **FileGlobals** and **StationGlobals**, which need to be present for a LTT testplan to work properly. A LTT testplan need to have an item named **LTT** and of type **LTT\_Client\_Data** placed in its FileGlobals.

![FileGlobals](/docs/assets/ltt/assets/ts-fileglobals.png)

The `FileGlobals.LTT.CFG` container contains variables representing the current test configuration. Those variables are automatically filled at start.

**TestStation, DutName, DutType, Group, OrderName, QualName**

Those variables are filled with the data entered in [F11 dialog](../LTTGUI/Dialogs/F11testconfiguration/) of LTT GUI.

**BasePath**

Path to the directory where your LTT sequence file is located.

**PS\_Index, PS\_Indizes, TS\_Index, TS\_Indizes**

A DUT belongs to a [test group](/en/docs/ltt/documentation/ltt-gui-manual/lttgui/dialogs/f3projectwizard/testgroupsconfiguration) and a test group can have one or more power supplies and temperature sensors assigned. The _X\_Index_ variable holds the **zero based (!)** index of the assigned power supply/temperature sensor, whereas the _X\_Indizes_ array holds all assigned indexes. You rarely need to use those since the assigned PS and TS are automatically controlled and usually do not need your further assistance.

![FileGlobals CFG](/docs/assets/ltt/assets/ts-fileglobals-cfg.png)

The `FileGlobals.LTT.RV` container contains variables representing various runtime values which get updated frequently during testplan execution.

**Runtime, Cycles**

The current runtime of this test in seconds. The current [cycles](/en/docs/ltt/documentation/ltt-gui-manual/teststand/customsteptypes/cyclestartend) of this test.

**OpModeSeq, OpMode**

The currently executing operation mode. Note that the variable _OpModeSeq_ holds the exact sequence name, whereas the variable _OpMode_ holds the name of the operation mode (without the sequence prefix).

**HW**

`FileGlobals.LTT.RV.HW` contains voltages and currents of all configured power supplies as well as the temperatures of all configured temperature sensors. Use the `FileGlobals.LTT.CFG.XX_Index` variables to determine which PS/TS is relevant for that particular DUT.

**HW.TCC**

The current TCC value. Please note that this value is not [masked](/en/docs/ltt/documentation/ltt-gui-manual/lttgui/dialogs/f3projectwizard/testgroupsconfiguration). It represents the value of all 8 bits of the TCC input.

![FileGlobals RV](/docs/assets/ltt/assets/ts-fileglobals-rv.png)

A LTT testplan need to have an item named **LTT** and of type **LTT\_Global\_Settings** placed in its StationGlobals.

![StationGlobals](/docs/assets/ltt/assets/ts-stationglobals.png)

The `StationGlobals.LTT` container is mainly used for internal parameters which you do not need to know or modify, nor should you. An exception is the `StationGlobals.LTT.MESSY` container. In that you will find some variables of relevance.

| Variable     | Description                                                                                                                                                                                                                                                               |
| ------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| ENABLED      | If false no MesSy setup is performed in LTT process model. This can be used to run a LTT testplan without MesSy. Be aware that if you have MesSy API calls in your testplan those will fail. You can, however, check this variable as a precondition in every MesSy step. |
| ERR\_TOL\_MS | TODO: description. (for MesSy V1 compatibility)                                                                                                                                                                                                                           |
| TIMEOUT\_S   | MesSy communication timeout.                                                                                                                                                                                                                                              |
| VERSION      | MesSy version: 1 or 2. This is set by GUI!                                                                                                                                                                                                                                |