---
title: "KNX functions in Link’nX: create, edit, enable or delete"
description: Create a KNX hysteresis or presence detection function in Link’nX, then edit, suspend or delete it from the function list, without any scenario.
canonical: https://wiki.can-nx.com/en/guides/link-function-edit/
language: en
product: Link’nX
audience:
  - administrateur
  - installateur
context: "Link’nX web: Functions, function list and editor, preview beside or below the form"
---

# KNX functions in Link’nX: create, edit, enable or delete

Context: Link’nX web: Functions, function list and editor, preview beside or below the form

A Link’nX function monitors KNX group addresses and directly commands a target address, without going through a scenario. There are two types: hysteresis, which reacts to two thresholds on a measurement, and presence detection, which sends a command after a period without telegrams.

Intended for administrators and installers who know the KNX commands of their installation. The settings specific to each type are described in the guides to [hysteresis thresholds](https://wiki.can-nx.com/en/guides/link-function-hysteresis/) and to the [timer without telegrams](https://wiki.can-nx.com/en/guides/link-function-presence/).

## Find your functions

Check the project and the gateway displayed, then open **Functions** in the navigation. The **Function list** groups the cards into **Hysteresis** and **Presence detection**, with the number of functions in each group. Within each group, the functions are sorted by name.

| Card | Information shown |
| --- | --- |
| Hysteresis | **Source KNX**, **Target KNX**, **Low threshold** and **High threshold**, with the values to send |
| Presence detection | **Delay** in minutes, **Value to send** and **Sources** |

A presence card only writes out the first two sources. The additional count and the list icon **Show remaining sources** point to the others. To read all the addresses, especially on a touch screen, open **Edit**.

## Create a function

1. Click **Add**. The page displays **Create function**.
2. Fill in **Function name**: required, 80 characters maximum. Choose an explicit name, not made only of spaces.
3. In **Function type**, choose **Hysteresis** or **Presence detection**, then fill in its settings using the corresponding guide.
4. Check the switch at the top of the form. A new function is initially **Enabled**: once saved, it can command its target. Switch it to **Disabled** to prepare its configuration without putting it into service.
5. Reread **Live preview** and **Runtime interpretation**, which reflect your entry. This summary is next to the form on a large screen and below it on a narrower screen.
6. Click **Save** below the settings. After **Saved successfully**, the interface returns to the list.

## Edit a function

1. Click the **Edit** pencil at the bottom of the card. The page displays **Edit function**.
2. Edit the fields, then click **Update**.
3. Wait for **Updated successfully** and check the card.

The **Function type** remains editable: changing the type replaces the behavior kept when saving. Reread all the settings of the new type before confirming.

Before leaving a creation or edit form, save it with **Save** or **Update**, especially after adding or removing sources. Otherwise, the **Unsaved changes** window may offer **Cancel**, **Don't save** and **Save**.

## Enable or disable a function

In the list, the **Enable or disable function** switch at the bottom of the card changes its state without opening the editor. Wait for **Updated!**, then check **Enabled** or **Disabled** on the card.

Disabling sends no reverse command to equipment already actuated.

## Delete a function

1. Click the **Delete** trash can on the card.
2. The browser window asks **Delete function** with its name. Cancel to keep it, or confirm to request its deletion.
3. After **Deleted!**, check that the card has disappeared.

The list does not offer any restoration: to only suspend the function, use its switch. Deletion does not reverse commands already sent either.

## Check the result

After each confirmation, find the card in the list and check its type, its state and its settings. The form preview shows your entry; the card shows what is saved. Then watch the target equipment when the function’s condition occurs to see its effect on the installation.

## Troubleshooting

- **Please fill in all required fields**: check the name, then the settings of the chosen type.
- **Error saving**, **Error updating**, a state that is not confirmed or an unexpected list: follow the [function troubleshooting](https://wiki.can-nx.com/en/guides/link-function-help/).

If the result remains uncertain, contact support@can-nx.com.