Third-party OPC Client Connectivity

The Open Communication Standard (OPC) is a standard that ensures data exchange between multi-vendor devices and control applications without any proprietary restrictions.

OPC is implemented in client-server pairs.

  • The OPC server is a software program that converts the hardware communication protocol used by a device into the OPC protocol.
  • The OPC client software is any program that needs to connect to the hardware, such as a human-machine interface.

OPC DA

The OPC Data Access (OPC DA) specification defines the exchange of real-time data so that Desigo CC can be configured to interoperate with OPC-based field subsystems or devices.

The Desigo CC OPC client uses third-party OPC servers to obtain data from or send commands to the field hardware devices.

 

Information

Do not confuse Desigo CC server and client stations with the OPC clients and OPC servers. In this OPC-based application, Desigo CC server acts as an OPC client (the requester), while the connected hardware devices act as the OPC servers (responders).

OPC Servers

The third-party OPC-based field devices/subsystems that you want to connect to Desigo CC are integrated as third-party OPC servers. At a high level, an OPC server is comprised of several objects: server, group, and item.

  • The OPC server maintains information about itself and serves as a container for OPC groups.
  • The OPC group maintains information about itself and provides the mechanisms for containing and logically organizing OPC items. For example, the group might represent items in a particular operator display or report.
  • The OPC items represent connections to data sources (individual field data points) within the server.

OPC Items

To integrate one or more OPC devices or subsystems into Desigo CC, you must manually edit an OPC devices configuration CSV file that defines the server-groups-items structure for the devices. Then you import that CSV file into Desigo CC, to recreate that hierarchy under an OPC network in the System Browser tree. Each OPC server contains the related groups, and each group contains the related OPC items.

Third-party OPC Client Connectivity Limits

The current version of Desigo CC supports one or more OPC drivers, each one associated with an OPC network. The minimum configuration requires one OPC server configured in an OPC network. The maximum configuration is 20 OPC servers for each OPC network.

OPC in Distributed Systems

  • You can carry out the import operation for a system (System 1) from another system (System 2).
  • If you access the network of a system (System 1) from another system (System 2), then the drivers of System 1 display.
  • You cannot associate the logical view or any user-defined view root node of a system (System 1) with the hierarchies mapping of another system (System 2).