> For the complete documentation index, see [llms.txt](https://docs.irs.systems/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.irs.systems/ltt/documentation/ltt-gui-manual/teststand/operationmodes/parameters.md).

# Parameters

Although not mandatory it is common for an operation mode to have parameters.

{% hint style="info" %}
Operation mode parameters are defined as FileGlobal variables in TestStand.
{% endhint %}

![Operation Mode Parameter](/files/81zZeEcn3wsJje27hxWl)

The `FileGlobals.LTT.OM` structure is an array of containers. Each container represents the parameters for a single operation mode sequence. **The container must be named exactly like the operation mode sequence itself**. Within each operation mode parameter container you can add as many variables as needed. **Only variables of type *****string*****, *****bool***** and *****numeric***** are supported**.

For each operation mode parameter variable you set a **name**, a **default value** and a **description** (as variable comment). When the testplan is loaded in GUI you can see a list of all operation modes with their parameters in [F10 dialog](/ltt/documentation/ltt-gui-manual/lttgui/dialogs/f10testparameterconfiguration.md). There you can modify individual parameters, even during the testplan is running. The default parameter values entered in TestStand remain untouched. If you run without GUI you work with the default parameters. You need to change the values in TestStand if they do not fit your current need.

![Operation Mode Parameter Compare](/files/aGfdZloMMEJp0bZidSSS)


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://docs.irs.systems/ltt/documentation/ltt-gui-manual/teststand/operationmodes/parameters.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.