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

# system.tag.writeSynchronous

> Performs a write to a tag, synchronously.

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](projects\project-properties\project-properties.md#client---permissions) restrictions.

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

### Parameters

| Type | Parameter | Description |
|---|---|---|
| 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
Client

## Syntax - Gateway
`system.tag.writeSynchronous(tagPath, value)`

### Parameters

| Type | Parameter | Description |
|---|---|---|
| String | `tagPath` | The path of the tag to write to. |
| Object | `value` | The value to write. |

### Returns
Nothing

### Scope
Gateway

## 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.
```