How to Add a Connector

Connectors retrieve data from data sources, acting as the client to connect to servers. Configuring a Connector object in DataStudio allows the Connector service to connect to the Core and is therefore a key step when starting to use system:inmation.

Before creating a Connector object in DataStudio, a running Connector service is required. If you install system:inmation using a default setup (using the Windows Installer), a Passive Connector service will be installed. During installation, the Connector Service can also be configured as an Active component. In both cases, the Connector service installed will have TLS-SRP security mode enabled. If you did not use the default setup, or you want to configure additional connector services, then Connector services can be configured using the Node Installer or the command line.

The Connector service can be installed as a "Passive" or "Active" service. Passive Connectors listen for incoming connection requests from the Core service whereas Active Connectors actively send connection requests to the Core service.

Configuring a Connector from Installation

This section will guide you through configuring a Connector object corresponding to the Connector service set up during installation of system:inmation.

  • Navigate to the I/O Model panel and expand the object tree to reveal the Core object. Create a Connector under the Core object by opening the context menu and selecting Admin  New  Services  Connector which will open the Create Connector wizard.

Adding a Connector - Context Menu
Figure 1. Adding a Connector - Context Menu
  • In the Common section of the Create Connector wizard, enter an Object Name:

    • For a Passive Connector, it is recommended that the Object Name represents what the Connector is used for.

    • For an Active Connector, the Object Name must match the name of the host machine the Connector service is installed on.

Create Connector Wizard
Figure 2. Create Connector Wizard
  • Add an optional description and click Next.

  • In the Communication Settings, specify a Host Name or IP Address for the Connector Service. For a local connector, set this to 'localhost'.

  • The Connection Mode is dependent on whether the Connector service was installed as a Passive or Active component and should be set accordingly.

  • Enter the Passphrase assigned to the Connector Service on installation.

An automatic connection between the service and the system is not possible, because, on installation, new services use TLS-SRP for Intercomponent Communication. For this security mode, the same passphrase has to be provided on both ends of the connection (the service and the corresponding object in the system). When the connection is established, the security mode can be changed in DataStudio.
Create Connector - Communication Settings
Figure 3. Create Connector - Communication Settings
Advanced Communication Settings

The Communication Settings are of significant importance when the Connector is running in a remote location and listening on a different TCP port to the default one. These details are required when configuring the connector.

The Timeout property is crucial when long distance connections with high network lag times are used. If a TCP packet between Connector and Core requires more time than the specified timeout, the Connector will be disconnected and a reconnection initiated. To avoid unnecessary reconnects over slow network connections, it is recommended to increase the timeout to a higher value.

  • Click Create to create the object in the I/O Model.

The Connector object should now be visible in the I/O Model under the Core object. If there are any OPC Servers available to the Connector, they will be automatically visible in the tree below the Connector as Data Source items.

Additional Configuration Options

There are additional options that can be used for Connector configuration. Select the Connector object in the I/O Model and navigate to the Object Properties Panel.

  • The DCOM Credentials options can be used to specify account details if the Connector requires permission to read from a certain data source.

  • The Connector Options section is used to specify whether the Connector will automatically enable any data sources by default and optionally, bypass any discovery rules in place. There is also the option to disable the discovery mechanisms of certain OPC data sources. The use of whitelists/blacklists to control datasource discovery is explained in the Datasource Discovery section.

  • The OPC UA Stack options allow specific configuration of the connection to OPC UA data sources.

  • The Script Library is used to set the script library compound that contains Lua Script libraries.

  • In the Location section, the specific location details of the Connector can be configured. This section can also be used to specify if the location should be tracked.

  • In the Store and Forward Retention Method section, the buffering functionality of the Connector can be configured. This starts when the communication between Core and Connector is interrupted. In this case, the Connector buffers all data it should pass to the Core. By default, buffering data is kept on the local hard disk until it reaches 20GB. Once the maximum size is reached, new data is kept and "old" data is purged from the buffer.

    Data purged from the Store and Forward buffer is lost. Make sure that that specified GB size for the buffer is actually available on the hard disk that hosts the system:inmation installation. If there is insufficient memory on this hard disk, the Data Source object will be in a warning (yellow) state in the I/O Model Panel.
  • The remaining sections in the Object Properties Panel allow the configuration of Store and Forward options, Transmission Limits and other custom properties. See Connector Object Properties for more details on specific properties.

Datasource Discovery

In the Connector Options property group, the discovery of Datasources by the Connector service can be configured via the Whitelist and Blacklist tables.

Connector Options - Whitelist/Blacklist
Figure 4. Connector Options - Whitelist/Blacklist

Whitelist

  • Click on the table icon to open the Datasource Whitelist table. In the table, enter the full Object Name of the Datasource you wish to Whitelist (the Datasource will be automatically added on discovery by the Connector service). You can also drag and drop a Datasource from the I/O model into the table.

Datasource Whitelist
Figure 5. Datasource Whitelist
  • Click Ok to save the Datasource to the Whitelist and click Apply in the Object Properties panel to confirm the changes.

If the Whitelist is left empty, then all datasources (except those on the Blacklist) will be automatically discovered and added.

Blacklist

  • To add a Datasource to the Blacklist, click on the table icon to open the Blacklist table.

Datasource Blacklist
Figure 6. Datasource Blacklist
  • By default, the inmation OPC Classic server Datasource is on the Datasource blacklist. This means that the server will not automatically appear in the I/O Model when discovered by the Connector service. If the inmation server is removed from the Blacklist, it will be discovered and then can be browsed in the I/O Model (this is not recommended unless connecting to a server that is part of another inmation system).

  • Drag and drop another OPC datasource into the blacklist table (for example, the Matrikon simulation server) and click Ok. Then, click Apply in the Object Properties panel to confirm the changes.

Blacklist with Server added
Figure 7. Blacklist with Server added
  • Delete the Matrikon Simulation Server Datasource in the I/O Model then restart the Connector service in Windows Task Manager.

  • After restart, the Datasources on the Blacklist are no longer added to the I/O Model underneath the Connector object.

The Blacklist has priority over the Whitelist so if the same Datasource is added to both lists, the Blacklist overrules and the Datasource will not be automatically added to the I/O Model.

Under the Datasource Discovery Suppression property group, it is possible to completely disable the automatic discovery of all OPC Classic Datasources or all OPC UA Datasources. By default, automatic discovery of OPC UA servers is disabled.

Configuring Additional Connectors

Multiple Connector instances can be created (and connected to the Core) on the same host. Please see the documentation on installing multiple instances of services for more configuration details.

Passive Connectors

When creating Connector objects for additional Passive Connector services, the Listener Port needs to be stated in the Communication Settings. This Listener Port should match the port specified during the configuration of the additional Passive Connector service.

Active Connectors

In general, when configuring Connector objects for Active Connector services, the Object Name must match the host name of the machine where the service is installed but there are some exceptions to this:

This is only required for the initial connection and can be changed after the Connector object is configured.