====== Datanodes ======

| Datanode | Represents a virtual device that provides data from various physical devices or external services. It contains one or more signals, variables, or values used by the Mervis SCADA system. |
| Datahub | Manages your datanode and handles its communication and data storage. |

The datanode type determines how data is acquired:

  * **IoT LoRa types** (e.g., uh30, prolora, elliot…) – receive data from ČRA and usually correspond to a specific physical device such as an electricity or water meter.
  * **HTTP types** (e.g., gasnet, spotrebapodpalcem, distribuce24…) – actively retrieve data from external APIs. These don’t always correspond to a single device – data may be aggregated, processed by a service, or a single datanode may serve hundreds of physical devices.

In the user interface, you can configure basic parameters and type-specific properties of the datanode.  
It is also possible to assign a datanode to a **datahub**, especially if multiple datahubs are available in the domain.

| Datahub | Manages your datanode and handles its communication and data storage. |

{{:cs:mervis-scada:30-portal:portal_datanodes.png?direct|}}

**Main actions:**
  * **Edit Datanode** – allows you to modify the parameters of an existing datanode {{:cs:mervis-scada:30-portal:portal_edit_proj_icon.png?20|}}
  * **Delete Datanode** – allows you to delete the selected datanode {{:cs:mervis-scada:30-portal:portal_delete_proj_icon.png?20|}}

**Buttons:**
  * **Create Datanode** – opens a modal window for creating a new datanode  
  * **Datanode Variables** – opens a modal window displaying the datanode’s variables  
  * **Datanode Events** – opens a modal window displaying the datanode’s events

===== Create Datanode =====

Modal window for creating a new datanode

{{:cs:mervis-scada:30-portal:portal_create_datanode.png?direct|}}

In this window, you can set the datanode parameters:

  * **Name** – the name of the datanode  
  * **Datahub** – select the datahub. If there is only one available in the domain, this field is hidden. Otherwise, select the one that matches the datanode's configuration and type.  
  * **Database profile** – the datanode’s database profile  
  * **Type** – the type of datanode, which determines which properties are configurable  
  * **Datanode type properties** – properties specific to the selected datanode type.  
    If a row is highlighted in red, it is a required field and must be filled in.  
    If not highlighted, the property is optional and may remain empty.  
    Some fields may have default values pre-filled.

===== Datanode Variables =====

Modal window showing a list of available datanode variables and their most recent known value in the Mervis system, along with a timestamp.

{{:cs:mervis-scada:30-portal:portal_datanode_variables.png?direct|}}

===== Datanode Events =====

Modal window displaying the events of the datanode.  
This shows the current status of the given datanode and is useful for diagnosing datanode errors.

{{:cs:mervis-scada:30-portal:portal_datanode_events.png?direct|}}