OPC Data Exchange Center

Summary

The OPC Data Exchange Center OPC-DXC handles the data exchange between OPC servers and allows client to access data in all connected OPC servers. OPC DA and OPC XML-DA servers are supported. OPC DA servers need to be on a local network while XML-DA servers may be remote.
OPC-DXC is implemented as a .Net web service and is functionally an extended OPC DX server and OPC DX configuration client. The OPC DX compliant part allows clients to read data from multiple OPC servers through connections with all the OPC DX defined data handling. The extended functionality allows clients to write data to multiple OPC servers and transfer data between OPC servers. The write and transfer connections are configured in way very similar to the OPC DX read connections.

Read Data from multiple OPC servers

	An OPC DX connection has to be configured for each server item to be accessed. These connections support sophisticated data handling like substitute and override values, status monitoring and buffering. | Connections can be reconfigured and redirected from a configuration client during run-time. The connection status information can be read by a OPC DX configuration client using the OPC DX defined API or by an OPC DA client by reading the connection status items.
Reading data from multiple servers is OPC DX and OPC XML-DA compliant. XML-DA and OPC DX web service clients can access OPC-DXC directly, while OPC DA clients require an OPC DA to XML-DA gateway. Such are available from Technosoftware Inc. and other suppliers.

Writing Data to OPC Servers

Clients can write to any writable item in the connected OPC servers. A Write Bridge has to be configured for each item that needs write access. The configuration handling is similar to the handling of the OPC DX connections for read access. Clients can not only monitor the OPC servers but also write data to the OP server.

Transfering Data between OPC servers

Data can be directly transferred between connected OPC servers. An item from one OPC server can be automatically updated in one or multiple OPC servers. When the value of the source item changes then the target items are updated. An Xfer Bridge has to be configured for each target item. For the source items a DX connection needs to be configured. The Xfer Bridge takes the data from the DX connection, allowing for override and substitute values also in direct server transfers.

Configuration

The OPC-DXC Data Exchange Center offers an extended OPC DX web service configuration interface. A configuration client is provided as a .Net applications. Multiple OPC-DXC Data Exchange Centers can be configured from remote locations, depending on .Net access rights.
Configuration changes can be made during normal operation and are automatically persisted.

Monitoring

The OPC-DXC Data Exchange Center status can be examined with the OPC-DXC configuration client. OPC-DXC maintains status information for each OPC server and connection definition including current status, error counter, last access time etc.
The status information is also accessible as OPC DA data items. XML-DA clients can browse the items of OPC-DXC and read the configuration and status information.