OPC Classic

The abbreviation OPC Classic (OLE for Process Control) refers to an interface which is defined and expanded by the OPC Foundation. OPC Classic is widely used in process automation, in particular for coupling process data to HMI systems.

OPC Classic is based on a client-server structure. A client (master) can access one or several servers (slaves). Several clients can simultaneously access one server. One server provides the data and the client receives the data from the server. Although the client can also transmit data to the server, the main direction of data flow is from the server to the client.

OPC Classic comprises a number of interfaces which serve various purposes. The most important are:

  • DA (Data Access)
    this is probably the most widely used interface defining interfaces and methods for accessing process data
  • AE (Alarm and Event)
    is an add-on to the DA interface and enables the transmission of events and alarms
  • HD (Historical Data)
    is an add-on to the DA interface and enables the transmission of historical data 
  • DA XML
    This interface is a fairly recent addition based on the DA interface. Data encoding is however based on XML (eXtended Markup Language).

Unlike other protocols which have mainly been developed for the transmission of process data, the OPC Foundation allows users to verify the compliance of the server implementation with the standard. This is done with the Compliance Test Tool (CTT), a software package which is made available to members free of charge. If the server passes the compliance test, a document is generated as compatibility proof and functional reference. The CCT enables the user to virtually eliminate incompatibilities between implementations from different manufacturers and ensure smooth integration.

In addition, workshops are organized on a regular basis, where different manufacturers can benchmark their systems against each other. 

ISO/OSI Model

7 Application Layer OPC DA, AE, HD etc.OPC DA XML
6 Presentation Layer COM/DCOM
(Distributed) Component Object Model
SOAP, XML
5 Session Layer RPC
Remote Procedure Calls
HTTP
4 Transport Layer TCP/IP
3 Network Layer
2 Link Layer
1 Physical Layer

Available Protocol Stacks

OPC AE 1.10, Client

OPC AE 1.10, Server

OPC DA 3.0, Client

OPC DAXML 1.01, Server

OPC DA 3.0, Server

Applicable Products

  • ipConvOPC
    ipConvOPC

    Windows software package for universal conversion between diverse standard protocols

  • ipConv
    ipConv

    Universal protocol converter for highest degree of flexibility

  • ipConvLite
    ipConvLite

    Universal protocol converter for small and distributed applications

  • ipConvLite/MEC2PBS
    ipConvLite/MEC2PBS

    Universal protocol converter with integrated PROFIBUS-DP, slave interface

  • ipConvLite/MEC2PBM
    ipConvLite/MEC2PBM

    Universal protocol converter with integrated PROFIBUS-DP, master interface

  • ipConvLite/MEC2PNS
    ipConvLite/MEC2PNS

    Universal protocol converter with integrated PROFINET-IO, slave interface

  • ip4Cloud
    ip4Cloud

    Link critical processes securely to IT/Cloud/SCADA services

  • ip4Cloud/SEC3PB
    ip4Cloud/SEC3PB

    Capture PROFIBUS data by eavesdropping and transmit it to Cloud/IT or SCADA services

  • ip4Cloud/SEC3IO
    ip4Cloud/SEC3IO

    Switch and monitor digital I/O states to transmit them to IT/Cloud/SCADA services

References

  • BLS AlpTransit - Lötschbergtunnel
    BLS AlpTransit - Lötschbergtunnel, Switzerland

    Products: ipConv ipRoute
    Protocol Stacks: OPC DA 3.0, Server IEC 60870-5-104, Slave IEC 60870-5-101, Master IEC 60870-5-104, Master SNMP, Client

  • Mainova Communication Hub
    Mainova Communication Hub, Germany

    Products: ipConv
    Protocol Stacks: OPC DAXML 1.01, Server IEC 60870-5-104, Slave IEC 60870-5-101, Master Modbus, Master SEAB 1F, Master

  • ABBOPC1013
    ABBOPC1013, Switzerland

    Products: ipConv
    Protocol Stacks: IEC 60870-5-101, Slave IEC 60870-5-103, Master OPC DA 3.0, Server OPC DA 3.0, Client OPC AE 1.10, Client OPC AE 1.10, Server

  • RWE Mosel Hydro Power Stations
    RWE Mosel Hydro Power Stations, Germany

    Products: ipConvOPC ipRoute
    Protocol Stacks: OPC DA 3.0, Server IEC 60870-5-104, Master

  • Andritz Hydro GmbH, A-Vienna
    Andritz Hydro GmbH, A-Vienna, South Africa

    Products: ipConvOPC
    Protocol Stacks: IEC 60870-5-104, Master OPC DA 3.0, Server

  • ABBOPC104
    ABBOPC104, Austria

    Products: ipConv
    Protocol Stacks: IEC 60870-5-104, Slave OPC AE 1.10, Client OPC DA 3.0, Client

  • FHKW Linz
    FHKW Linz, Austria

    Products: ipConvOPC
    Protocol Stacks: OPC DA 3.0, Server IEC 60870-5-104, Master