---
title: "system.vision.openWindowInstance"
description: "Operates exactly like system.vision.openWindow, except that if the named window is already open, then an additional instance of the window will be opened."
---

# system.vision.openWindowInstance

> Operates exactly like system.vision.openWindow, except that if the named window is already open, then an additional instance of the window will be opened.

:::info Backwards Compatibility
This function replaces [system.nav.openWindowInstance](versioned_docs/version-8.1/appendix/scripting-functions/system-nav/system-nav-openWindowInstance.md). Any scripts containing Vision Client scoped functions that were replaced with system.vision syntax will still work to maintain backwards compatibility.
:::

This function is used in **Python Scripting**.

## Description
When called in a Vision Client, it operates exactly like [system.vision.openWindow()](appendix\scripting-functions\system-vision\system-vision-openWindow.md), except that if the named window is already open, then an additional instance of the window will be opened. There is no limit to the number of additional instances of a window that you can open.

When called in the Designer, it operates similar to system.vision.openWindow(), except that if the named window is already open the function will swap to the opened window. Additional instances will not be opened. A warning is issued indicating why a new instance was not opened.

:::note
This function is available on secondary desktops via the [system.vision.desktop](system-vision-desktop.md) function. See the [Multi-Monitor Clients](ignition-modules\vision\common-tasks-in-vision\multi-monitor-clients\multi-monitor-clients.md) page for more details on secondary desktops.
:::

## Client Permission Restrictions
This scripting function has no [Client Permission](../../../ignition-modules/vision/vision-project-properties/vision-project-properties.md#vision-permissions-properties) restrictions.

## Syntax
`system.vision.openWindowInstance(path, [params])`

### Parameters
Type | Parameter | Description 
------- | ------- | ------
String| `path` | The path to the window to open.
Dictionary[String, Any]| `params` | A dictionary of parameters to pass into the window. The keys in the dictionary must match dynamic property names on the target window's root container. The values for each key will be used to set those properties. [optional]

### Returns
**Window** - A reference to window that was navigated to. Refer to the list of [window](appendix\components\vision-components\vision-window-object\vision-window-object.md) objects.

### Scope
Vision Client

## Code Examples
```python title="Example #1"
# This example would open three copies of a single HOA popup screen.
  
system.vision.openWindowInstance("HOA", {machineNum:3})
system.vision.openWindowInstance("HOA", {machineNum:4})
system.vision.openWindowInstance("HOA", {machineNum:5})
```