> For the complete documentation index, see [llms.txt](https://support.powerio.com/hub/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://support.powerio.com/hub/faq-and-news/en/hvac-codesys-faq/automatischer-neustart-im-fehlerfall.md).

# Automatic restart in case of error

{% hint style="warning" %}
Please note that for the full functionality of the feature *OnException* **you require at least firmware version 3.2** .

The feature *OnException* is preconfigured for powerIO devices and is recommended only for powerIO devices.
{% endhint %}

## How can the controller be automatically restarted in case of an error?

The following article describes the function of how an exception error can be logged during runtime and how the runtime or the device can be restarted in the exceptional state.

## Description

* That the controller on an exception **without** **"emergency stop"** (no kernel panic) of the system, the message is logged and a restart of the CODESYS runtime takes place. This is the “automatic soft reset in case of error”.
* That the controller on an exception **with “emergency stop”** (kernel panic) of the system, the message *attempts* to log and a restart of the system occurs.

  This is the “automatic hard reset in case of error”

## Function description *OnExceptionWrapper*

In the [start project "Empty" ](/hub/downloads/en/codesys-hvac-templates/template-start.md)are located under the view *POU* the two functions

* *OnException* and
* *OnExceptionWrapper*

The feature *OnExceptionWrapper*, calls the *OnException* function with the specified settings.

```iecst
OnException( 
	EventPrm:=EventPrm,
	xDebug := FALSE,
	xLogExceptionToFile:=TRUE,
	xRestartRuntimeOnException := TRUE,
	tExceptionFunctionTimeout := TIME#45S0MS
	);
```

## Enable/disable the exception handling function

1\. Click on "Task configuration"

![](https://ajeuwbhvhr.cloudimg.io/colony-recorder.s3.amazonaws.com/files/2023-11-21/a17783ad-3118-4508-870f-28e2ff3d4f84/user_cropped_screenshot.jpeg?tl_px=0,231\&br_px=859,712\&force_format=png\&width=860\&wat_scale=76\&wat=1\&wat_opacity=1\&wat_gravity=northwest\&wat_url=https://colony-recorder.s3.amazonaws.com/images/watermarks/77328A_standard.png\&wat_pad=122,212)

2\. Click on "System events"

![](https://ajeuwbhvhr.cloudimg.io/colony-recorder.s3.amazonaws.com/files/2023-11-21/17d6f9e5-ba67-49c0-a42f-e26e029ddea3/user_cropped_screenshot.jpeg?tl_px=274,0\&br_px=1134,480\&force_format=png\&width=860\&wat_scale=76\&wat=1\&wat_opacity=1\&wat_gravity=northwest\&wat_url=https://colony-recorder.s3.amazonaws.com/images/watermarks/77328A_standard.png\&wat_pad=402,107)

3\. Check if the "Exception" function is already present.

![](https://ajeuwbhvhr.cloudimg.io/colony-recorder.s3.amazonaws.com/files/2023-11-21/959b345f-8448-402d-9740-889e366bafed/user_cropped_screenshot.jpeg?tl_px=195,0\&br_px=1055,480\&force_format=png\&width=860\&wat_scale=76\&wat=1\&wat_opacity=1\&wat_gravity=northwest\&wat_url=https://colony-recorder.s3.amazonaws.com/images/watermarks/77328A_standard.png\&wat_pad=402,173)

4\. If present, check if it is "Active"

![](https://ajeuwbhvhr.cloudimg.io/colony-recorder.s3.amazonaws.com/files/2023-11-21/97f6a3fb-6992-46d4-b3f4-0048d7d99f92/screenshot.jpeg?tl_px=1905,0\&br_px=2765,480\&force_format=png\&width=860\&wat_scale=76\&wat=1\&wat_opacity=1\&wat_gravity=northwest\&wat_url=https://colony-recorder.s3.amazonaws.com/images/watermarks/77328A_standard.png\&wat_pad=402,177)

5\. If not active, then activate it

![](https://ajeuwbhvhr.cloudimg.io/colony-recorder.s3.amazonaws.com/files/2023-11-21/6ed9e473-a7e9-40ab-a11b-3d5a7fb4ad65/screenshot.jpeg?tl_px=1905,0\&br_px=2765,480\&force_format=png\&width=860\&wat_scale=76\&wat=1\&wat_opacity=1\&wat_gravity=northwest\&wat_url=https://colony-recorder.s3.amazonaws.com/images/watermarks/77328A_standard.png\&wat_pad=402,177)

## Adding the exception handling function

If you want to add exception handling to an existing project, you can copy the two functions from the [start project "Empty" ](/hub/downloads/en/codesys-hvac-templates/template-start.md)and add the event task yourself.

To do this, proceed as described below:

1\. Navigate to "Task configuration"

![](https://ajeuwbhvhr.cloudimg.io/colony-recorder.s3.amazonaws.com/files/2023-11-21/b299d8ef-01ff-4bdf-a9e5-60610b76ab6e/user_cropped_screenshot.jpeg?tl_px=0,237\&br_px=859,718\&force_format=png\&width=860\&wat_scale=76\&wat=1\&wat_opacity=1\&wat_gravity=northwest\&wat_url=https://colony-recorder.s3.amazonaws.com/images/watermarks/77328A_standard.png\&wat_pad=166,212)

2\. Open the "System events" tab

![](https://ajeuwbhvhr.cloudimg.io/colony-recorder.s3.amazonaws.com/files/2023-11-21/fabaa8e3-458d-4506-be77-36339e0ddeec/user_cropped_screenshot.jpeg?tl_px=285,0\&br_px=1145,480\&force_format=png\&width=860\&wat_scale=76\&wat=1\&wat_opacity=1\&wat_gravity=northwest\&wat_url=https://colony-recorder.s3.amazonaws.com/images/watermarks/77328A_standard.png\&wat_pad=402,105)

3\. Click "Add event handler"

![](https://ajeuwbhvhr.cloudimg.io/colony-recorder.s3.amazonaws.com/files/2023-11-21/b8682791-790f-4cad-b089-b1c1d0b2499a/user_cropped_screenshot.jpeg?tl_px=46,0\&br_px=905,480\&force_format=png\&width=860\&wat_scale=76\&wat=1\&wat_opacity=1\&wat_gravity=northwest\&wat_url=https://colony-recorder.s3.amazonaws.com/images/watermarks/77328A_standard.png\&wat_pad=402,131)

4\. Select event type "Exception"

![](https://ajeuwbhvhr.cloudimg.io/colony-recorder.s3.amazonaws.com/files/2023-11-21/430c91c1-d6d7-4602-83a4-690c952034cb/user_cropped_screenshot.jpeg?tl_px=693,315\&br_px=1553,796\&force_format=png\&width=860\&wat_scale=76\&wat=1\&wat_opacity=1\&wat_gravity=northwest\&wat_url=https://colony-recorder.s3.amazonaws.com/images/watermarks/77328A_standard.png\&wat_pad=402,212)

5\. Enter exception name "OnExceptionWrapper"

![](https://ajeuwbhvhr.cloudimg.io/colony-recorder.s3.amazonaws.com/files/2023-11-21/d08770c6-8fe3-4339-88e2-ded86e4caad0/user_cropped_screenshot.jpeg?tl_px=494,279\&br_px=1258,706\&force_format=png\&width=764)

6\. Click "POUs"

![](https://ajeuwbhvhr.cloudimg.io/colony-recorder.s3.amazonaws.com/files/2023-11-21/586e7dc6-2d8e-4b1d-8352-cbb134b6478f/user_cropped_screenshot.jpeg?tl_px=803,293\&br_px=1568,720\&force_format=png\&width=764\&wat_scale=68\&wat=1\&wat_opacity=1\&wat_gravity=northwest\&wat_url=https://colony-recorder.s3.amazonaws.com/images/watermarks/77328A_standard.png\&wat_pad=357,188)

7\. Click "OK"

![](https://ajeuwbhvhr.cloudimg.io/colony-recorder.s3.amazonaws.com/files/2023-11-21/b407b030-9d13-48a1-9c06-bf8ba6c15cb6/user_cropped_screenshot.jpeg?tl_px=542,395\&br_px=1402,876\&force_format=png\&width=860\&wat_scale=76\&wat=1\&wat_opacity=1\&wat_gravity=northwest\&wat_url=https://colony-recorder.s3.amazonaws.com/images/watermarks/77328A_standard.png\&wat_pad=402,212)

8\. Switch the view to "POUs"

![](https://ajeuwbhvhr.cloudimg.io/colony-recorder.s3.amazonaws.com/files/2023-11-21/a0288e24-8490-45c5-a66b-b3926deb77a8/user_cropped_screenshot.jpeg?tl_px=0,1211\&br_px=859,1692\&force_format=png\&width=860\&wat_scale=76\&wat=1\&wat_opacity=1\&wat_gravity=northwest\&wat_url=https://colony-recorder.s3.amazonaws.com/images/watermarks/77328A_standard.png\&wat_pad=73,377)

9\. Open function "OnExceptionWrapper (FUN)"

![](https://ajeuwbhvhr.cloudimg.io/colony-recorder.s3.amazonaws.com/files/2023-11-21/90abd384-bc64-430d-8ada-452f8c7e72d6/user_cropped_screenshot.jpeg?tl_px=0,20\&br_px=859,501\&force_format=png\&width=860\&wat_scale=76\&wat=1\&wat_opacity=1\&wat_gravity=northwest\&wat_url=https://colony-recorder.s3.amazonaws.com/images/watermarks/77328A_standard.png\&wat_pad=143,212)

10\. Configure "OnException" function

![](https://ajeuwbhvhr.cloudimg.io/colony-recorder.s3.amazonaws.com/files/2023-11-21/a1ce65ed-e2d1-42b2-8a01-601add236224/user_cropped_screenshot.jpeg?tl_px=325,427\&br_px=1185,908\&force_format=png\&width=860\&wat_scale=76\&wat=1\&wat_opacity=1\&wat_gravity=northwest\&wat_url=https://colony-recorder.s3.amazonaws.com/images/watermarks/77328A_standard.png\&wat_pad=402,212)


---

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