# Changing MesSy Version

The new LTT software can be used with both **MesSy V2** and **MesSy V1**. During installation you have to choose for one option but you can switch to the other MesSy version at any time afterwards.

{% hint style="warning" %}
Before you setup the MesSy version in LTT software make sure that LTT GUI is closed.
{% endhint %}

To switch from one MesSy version to the other you need to perform some configuration changes in different places. The following table describes those changes.

| Location of change    | What to change                                            |
| --------------------- | --------------------------------------------------------- |
| ltt\_main\_config.xml | Change the parameter `<MessyVersion>X</MessyVersion>` to: |

```
- 1 for MesSy V1
- 2 for MesSy V2 |
```

\| ltt\_messy\_config.xml | The MesSy signal mapping file has a different format for MesSy V2 compared to MesSy V1.

You will find an example signal configuration for MesSy V1 here: `50_LTT_SW\LTT TS\examples\ltt_messy_config_V1.xml`

You will find an example signal configuration for MesSy V2 here: `50_LTT_SW\LTT TS\examples\ltt_messy_config_V2.xml`

Depending on what you have chosen during installation, one of those signal configuration files is copied to `50_LTT_SW\LTT Config\ltt_messy_config.xml` for use in a LTT testplan.

If you want to create a testplan for the other version of MesSy, simply copy the corresponding MesSy signal configuration file from `50_LTT_SW\LTT TS\examples\` to `50_LTT_SW\LTT Config\ltt_messy_config.xml`. | | LTT Template.seq | With the LTT installer there comes a LTT template sequence file - one for each MesSy version.

You will find the LTT template sequence file for MesSy V1 here: `50_LTT_SW\LTT TS\lib\IRS.MesSy\V1\LTT Template.seq`

You will find the LTT template sequence file for MesSy V2 here: `50_LTT_SW\LTT TS\lib\IRS.MesSy\LTT Template.seq`

Depending on what you have chosen during installation, one of those template sequence files is copied to `50_LTT_SW\LTT TS\LTT Template.seq`.

If you want to create a testplan for the other version of MesSy, simply copy the corresponding template sequence file to `50_LTT_SW\LTT TS\LTT Template.seq`. | | [LTT GUI - Project Wizard (F3)](/ltt/documentation/ltt-gui-manual/lttgui/dialogs/f3projectwizard.md) | Open the project wizard in LTT GUI and go to [Test Station Configuration](/ltt/documentation/ltt-gui-manual/lttgui/dialogs/f3projectwizard/teststationconfiguration.md). Read the corresponding chapter for more informations. |

{% hint style="info" %}
For TestStand integration read chapter [MesSy Integration](/ltt/documentation/ltt-gui-manual/teststand/messyintegration.md).
{% endhint %}


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