OPC Server

Help Contents

Introduction

OPC is a software interface standard that allows programs to communicate with industrial hardware devices. You can connect OPC aware client applications directly to Fernhill SCADA without needing any custom interface software:

Diagram showing Fernhill SCADA relationship with OPC clients

Fernhill SCADA supports these OPC Classic interfaces:

OPC Use Cases

Using the OPC Server and a suitable client application you can:

Supported Interfaces

Client applications access features in the OPC Server through standard interfaces. The specification of these interfaces is defined by the OPC foundation. The OPC Server in Fernhill SCADA supports these interfaces:

OPC Server
IOPCCommon
IOPCSecurityNT
IOPCServer
IOPCItemProperties
IOPCItemIO
IOPCBrowseServerAddressSpace
IOPCBrowse
IOPCEventServer
IOPCHDA_Server
IOPCHDA_SyncRead
IConnectionPointContainer

OPC Data Access groups support these interfaces:

OPC Data Access Group
IOPCItemMgt
IOPCGroupStateMgt
IOPCGroupStateMgt2
IOPCSyncIO
IOPCSyncIO2
IOPCAsyncIO
IOPCAsyncIO2
IOPCAsyncIO3
IOPCItemDeadbandMgt
IDataObject
IConnectionPointContainer

OPC Alarms and Events subscriptions support these interfaces:

OPC Event Subscription
IOPCEventSubscriptionMgt
IConnectionPointContainer

OPC Foundation

The OPC foundation is a non-profit organization that defines and promotes OPC standards for data exchange in Industrial Automation and other related domains.

DCOM

The Fernhill SCADA OPC Server is an in-process COM server, which avoids any need to set up DCOM.

When the OPC Client application is not on the same computer as Fernhill SCADA, install the OPC Server on the client computer. The Fernhill SCADA Setup program provides the install option Data Access Interfaces specifically for this. In this scenario, the OPC Client application loads the in-process OPC Server, which in turn communicates with Fernhill SCADA using TCP/IP.

The Fernhill SCADA OPC Server also supports out-of-process activation using the standard Windows DLL Surrogate DLLHost.exe, so you can use DCOM if you prefer.

Further Information

Diagnosing Connection Problems

If you are having problems connecting to a Fernhill SCADA Server.

OPC Server Administration Tool

To learn how to connect OPC Clients to different computers running Fernhill SCADA.

Link to Iconics Data Spy

For a guide to linking Iconics Data Spy to Fernhill SCADA.

Using C/C++ to access an OPC Server

For a guide to writing C/C++ code to access an OPC Server.

opcfoundation.org

For information about the OPC standards.

Glossary

For the meaning of terms used in Fernhill SCADA.