OPC Agent (Native OPC Client)

Iotellect OPC Agent is a Windows application that connects to a local OPC server running on the same machine and exposes OPC data to a Iotellect Server by connecting to this server as an Agent.

OPC Agent supports OPC DA, OPC HDA and OPC AE specifications, allowing Iotellect Server to access OPC tag current values and history, and OPC alerts/events that are converted to unified model events.

The Agent can be downloaded from the Iotellect, FZCO website. It's not licensed separately, however OPC data provided by the Agent is counted towards Iotellect Server license limits.

OPC Agent configuration groups are as follows:

• Iotellect Server Connection Settings:

  • Server address, port, username, device name of agent-type device, and password.

• OPC Server Settings:

  • Refresh time, and the DA, HDA and/or AE servers whose data will be exposed to Iotellect Server.

• Additional Settings:

  • Add server name as a variable name prefix as a way to avoid variable name collisions in Iotellect Server.

  • Add tag hash code as a variable name suffix as a way to avoid variable name collisions in Iotellect Server.

  • Enable DA filtering. See the following section for more information on how to configure tag filtering.

  • Logging is automatically enabled. Logs are located in <AGENT_INSTALL_DIR>/logs. Logging options can be configured in the <AGENT_INSTALL_DIR>/log4net.config by following the log4net documentation.

OPC server performance can be improved by using Tag Filtering in the OPC Agent configuration. Filtering becomes more important as the number of tags increases. See below for information about configuring tag filtering.

Tag filters are used to selectively control the data flow and processing of tags within a system, allowing users to define specific criteria or conditions to determine which tags are processed, and which ones are excluded.

Tag filters can be defined in a configuration file in the installation directory of the OPC Agent client:

• Navigate to the installation directory "Iotellect, FZCO OPC Agent" and open the file DAFilters.cfg

• Each line in the file indicates a single filter. Tags matching one or more filters will be processed. Tags which do not match any filter will be ignored. The filter format is <OPC server ID>;<tag access path filter>. See Filter Syntax for more details on constructing filters.

• Click Apply to save the changes and restart the agent.

• When the agent restarts, the driver should resynchronize and display only tags matching the filters in the configuration file.

Filters are created based on the notion of a tag hierarchy, with the dot . used to separate sub-paths.

Suppose the device can potentially have the following tags, with the indicated hierarchy:

• Simulation (root)

  • Square waves

    • property1

    • property2

    • Further paths…

  • Triangle waves

    • property1

    • property2

    • Further paths …

  • Further paths…

Some Example tags filters:

simulation.square waves.property1 - match exactly the tag "simulation.square waves.property1"
simulation.triangle waves.property# - match any tag with a "simulation.square waves.property" followed by a number
simulation.triangle waves.property[!1] - match any tag with a "simulation.square waves.property" followed by a character, except for the character "1"
simulation.triangle waves.* - match any tag in the subpaths of "simulation.triangle waves"
* match all tags

The following patterns can be used to match tags:

The matching patterns are applied according to the following rules:

• A group of one or more characters (charlist) enclosed in brackets [ ] can be used to match any single character in the string and can include almost any character code, including digits.

• By using a hyphen - to separate the upper and lower bounds of the range, charlist can specify a range of characters. The characters must appear in ascending sort order (from lowest to highest). For example, [A-Z] results in a match if the corresponding character position in string contains any uppercase letters in the range A-Z. Multiple ranges are included within the brackets without delimiters.

• To match the special characters left bracket [, question mark ?, number sign #, and asterisk *, enclose them in brackets. The right bracket ] cannot be used within a group to match itself, but it can be used outside a group as an individual character.

Other rules for pattern matching include the following:

• An exclamation mark ! at the beginning of charlist means that a match is made if any character except the characters in charlist is found in the string. When used outside brackets, the exclamation mark matches itself.

• A hyphen - can appear either at the beginning (after an exclamation mark if one is used) or at the end of charlist to match itself. In any other location, the hyphen is used to identify a range of characters.

• When a range of characters is specified, they must appear in ascending sort order (from lowest to highest). [A-Z] is a valid pattern, but [Z-A] is not.

• The character sequence [] is considered an empty string "".

• The filter is not case sensitive.

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