Source System

A source system refers to a specific data source from which data is to be queried. You need to make an entry in the PCo console for the computer or control device from which you want to query data.

The connection between the data source and PCo is established using agents. Agents are .NET DLL assembly components. In the PCo Management Console, you can create one or multiple source systems for an agent. You can then define one or multiple agent instances for each of these source systems. The agent instance establishes the actual data flow between the data source and PCo. (See also: Agent Instance.)

The source system in PCo is an adapter that converts the protocol-specific representation of data into a general and unified view. The source system performs the following tasks:

• A source system translates PCo commands such as queries or configuration parameters, for example, for a reliable connection, into protocol-specific commands.

• A source system transforms the server data in the data source into a tag-based data structure that can be browsed. A tag-based data structure is already given for some data sources (for example, OPC servers). For other data sources, such as the file system source system, the content must be transformed, that is, the content of a directory must be displayed as a node structure so that it can be browsed.

• It converts the protocol-specific data types, such as the time stamp, into the .NET data types that are used in PCo.

The table below contains the source systems available as standard in PCo. In addition, you can see for which communication processes each source system can be used:

• Query process (see also: Query Process (with SAP MII))

• Notification process (see also: Notification Process)

• Destination system calls with response processing (see also: Enhanced Method Processing (EMP) and PCo as OPC UA Server and as Web Server)

• Retrieve and store queries with the query destination system (see also: Query Destination System)