---
title: "system.tag.writeSynchronous"
description: "Performs a write to a tag, synchronously."
---

# system.tag.writeSynchronous

> Performs a write to a tag, synchronously.

:::note Deprecated
This function was deprecated in 8.1.0.
:::

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

## Description
Performs a write to a tag, synchronously. This means that you know at the end of this function whether or not the write succeeded or not. A write that fails or times out will throw an error. However, this function cannot be called from the event dispatch thread, which means that it cannot be called directly from a GUI event like a button press, without wrapping it in a system.util.invokeAsynchronous. You can call this from project event scripts like timer scripts.

## Client Permission Restrictions
This scripting function has no [Client Permission](versioned_docs/version-8.1\ignition-modules\vision\vision-project-properties\vision-project-properties.md#vision-permissions-properties) restrictions.

## Syntax
`system.tag.writeSynchronous(tagPath, value [, timeout])`

- Parameters
    - String `tagPath` - The path of the tag to write to.
    - Object `value` - The value to write.
    - int `timeout` - How long to wait in milliseconds before timing out pending writes. The default is 45000 milliseconds. [optional]
- Returns
    - Nothing
- Scope
    - All

## Code Examples
```python title="Example #1"
# This code would write the value 1 to a tag. It will continue immediately on success or failure, or wait up to 38 seconds if the write is pending.
  
system.tag.writeSynchronous("Tags/T5", 1, 38000)
# This line will not be reached until the tag write succeeds, fails, or has been
#  pending for at least 38 seconds.
```