---
title: Override the value of a KNX action in a Link’nX scenario
description: Reuse a KNX action in a Link’nX scenario with a value specific to one occurrence, without changing the action, and check its effect on each group address.
canonical: https://wiki.can-nx.com/en/guides/link-scenario-values/
language: en
product: Link’nX
audience:
  - administrateur
  - installateur
context: "Link’nX web: KNX action cards of the scenario form and Actions details window"
---

# Override the value of a KNX action in a Link’nX scenario

Context: Link’nX web: KNX action cards of the scenario form and Actions details window

In a Link’nX scenario, a KNX action can be added with a value specific to that occurrence in the sequence, instead of the values configured in the action. The same KNX action can thus be reused in a scenario with another value, without changing the original action.

Intended for installers and administrators who know the group addresses, data types and command values of the KNX action concerned.

## Before you start

- The KNX action is prepared with its addresses and reference values, as described in the [KNX action guide](https://wiki.can-nx.com/en/guides/link-action-knx/).
- The [scenario form](https://wiki.can-nx.com/en/guides/link-compose-scenario/) is open.

## Add the action with its own value

1. In **Actions**, search for and select the prepared KNX action.
2. Check **Override value**. The **Value** field becomes editable.
3. Enter the numeric value, zero or greater, suited to the command and its data type. The field may be prefilled: with the configured value if the action has a single address, with -1 if it has several. Always check the value; it is up to you to choose the one that suits the equipment.
4. Click **Add the action**. A new card appears in the list of actions.
5. Adjust the order and the delay of this card if necessary, then [save the scenario](https://wiki.can-nx.com/en/guides/link-scenario-save/) with the floppy disk at the bottom right.

## Understand the scope of the value

- The chosen value applies to this occurrence of the scenario. It does not replace the values saved in the action in the general **Actions** list.
- If the KNX action has several addresses, this same value is used for all the commands of this occurrence: check that it suits each of them and their data types.
- If the different addresses must receive different values, keep the values configured in the action, without applying a single value to this occurrence.

## Change or remove the value of an occurrence

To change an occurrence already present, locate its card and change **with the value**. To return to the values configured in the action, clear this field: the **by default** hint appears. Then save the scenario.

The same option exists in **Actions details**:

- in **Selected list**, choose the occurrence, then change its KNX **Value** field;
- in **Full list**, choose the action, then fill in **Override value** and **Value**, and click **Add action**.

After closing the window, review the card in the main form, then save. The [detail windows guide](https://wiki.can-nx.com/en/guides/link-scenario-details/) describes their other commands.

## Check the result

After adding, check that the new card shows the intended value in **with the value**. In the main form, the **Action added to list** message appears on every click on **Add the action**, even when the value is rejected: only the card confirms the addition.

To check the effect, the triangle in a circle on a card requests an immediate test of the action, with the card’s value when it is filled in. This test can control all the action’s addresses. It only tests this action and does not save the scenario. For a deliberate test, follow the [execution precautions and checks](https://wiki.can-nx.com/en/guides/link-run/).

## Troubleshooting

| Message or symptom | Cause | Action |
| --- | --- | --- |
| No card appears after adding | The value entered is rejected | Select the action again, check the checkbox and the value, then try again once. |
| **Set valid value!** | The value is negative | Enter a value zero or greater. |
| **Required** | The value is missing | Enter a value or, to reuse the action’s value, uncheck **Override value** before adding. |

Do not choose a value at random to work around a block. If you do not know the value suited to the data type, if your need concerns a negative value or text, or if the result does not match the planned commands, contact support@can-nx.com with the action name, the data types concerned and the result you are looking for.