> For the complete documentation index, see [llms.txt](https://docs.voltmasters.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.voltmasters.io/voltmasters-platform/10.-project-settings/10.7-ems-controller.md).

# EMS controller

Under **Settings → Project Settings → EMS Controller**, you can view and manage the operational controls for the physical EMS controller installed at the site.

### Advanced logging

Advanced logging stores additional technical data on the controller for diagnostic purposes. This data is used by Voltmasters Support during troubleshooting or investigations.

There is no download button available for end users. If you require an export of this data, contact Voltmasters Support directly.

### Restarting the controller

You can restart the EMS controller from within Voltmasters when a short interruption of control and device communication is acceptable.

<details>

<summary><strong>Will any data be lost?</strong></summary>

Your historical energy data in Voltmasters is normally preserved during a restart. Live control of devices is temporarily interrupted until the controller comes back online.

</details>

<details>

<summary><strong>How long does a restart take?</strong></summary>

Typically one to a few minutes, depending on your hardware and network connection.

</details>

<details>

<summary><strong>How do I know the restart is complete?</strong></summary>

Live values return to normal behaviour, any "controller offline" alert disappears, and the project dashboard status is correct again.

</details>

### Updating the controller

Software updates load new firmware onto the EMS controller. Where possible, plan updates outside of peak usage times.

<details>

<summary><strong>Will any data be lost?</strong></summary>

Like a restart, your energy history in Voltmasters is generally preserved. Expect a short interruption of control during the update process.

</details>

<details>

<summary><strong>How long does an update take?</strong></summary>

This depends on the download speed and installation time. Voltmasters Support can provide an estimate for your specific situation.

</details>

<details>

<summary><strong>How do I know the update is complete?</strong></summary>

Compare the firmware version number shown in the controller section of the project settings before and after the update. When the version number has changed, the update has been applied.

</details>

<details>

<summary><strong>Can I install a previous software version?</strong></summary>

The controller settings include a field to specify a target version. Leave this blank to use the standard version distributed by Voltmasters. Manually specifying an older version is best left to a specialist.

</details>

<details>

<summary><strong>Are automatic updates available?</strong></summary>

There is no automatic update toggle available for end users. Voltmasters controls which updates are distributed and when. Contact Voltmasters Support with any questions about update schedules.

</details>

### Troubleshooting: controller frequently offline

If your EMS controller regularly shows as offline in the platform, this typically indicates a network connectivity problem on your local network.

{% hint style="info" %}
Steps you can try yourself:
{% endhint %}

1. **Restart the router**: power it off, wait 30 seconds and power it back on.
2. **Check all cable connections**: verify that the network cables on the router and the controller are firmly seated.
3. **Check whether neighbours have the same problem at the same times**. If yes, the issue is likely with your internet provider rather than your local network.

If none of the above helps, have your network cabling and routers checked by a qualified network technician.

For detailed network requirements, including ports, domains, and DNS configuration, see [Internet and network](/getting-started/ems-controller-installation/internet-and-network.md).


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