OPC Products

OPC is an acronym for OLE for Process Control. OLE, an acronym for Object Linking and Embedding is a Microsoft technology developed to allow Windows applications to exchange information. OLE is available on Microsoft Windows 95/98 and Microsoft Windows NT operating systems. OLE is based on Distributed Component Object Model or DCOM. DCOM allows Clients to make use of an OPC server on a remote computer via a network. DCOM is part of Windows NT and can be added to Windows 95/98.

OPC is a standard written by the OPC Foundation for use in the manufacturing environment. It defines the way OLE is used so that OPC Clients can interact with OPC Servers.  This specification details the methods of exchanging data between data sources (servers) and data users (clients). The data exchange between servers and clients is possible between servers and clients residing on the same computer (local server) and between servers and clients residing on different computers over a network via Distribute Communication Object Modeling (DCOM) (remote servers) .

All DASTEC's Servers support the following:

  •      OPC 2.0 and OPC 1.0 specifications
  •      Explorer like configuration environment for easy configuration
  •      Montior mode for testing the communication links
  •      Scaling and deadbanding
  •      Client browsing

All Servers are built as out of process server, i.e., an executable program, supporting remote networking via DCOM. DASTEC's OPC Servers are all built using the FactorySoft OPC Server development kit. Only one Server type should be run on any one computer at a time.

Refer to DASTEC's web links, accessible from our sites menu, for links to sites providing additional OPC information and resources.

DASTEC's OPC Involvement History

DASTEC has been involved in developing OPC Servers since 1997. We began working with OPC Servers by evaluating the technology as part of investigating system designed requirements for customers and then by writing several in house Servers to more fully evaluate the technology. Evaluating several of the available OPC development packages on the market, DASTEC has chosen the OPC Server tool kit from FactorySoft on which to build its Servers. This ensures that all developed Servers are up to date with the latest OPC Foundation specifications and released Servers can quickly be recompiled to be brought up to date. During the development of our in house Servers, we developed extensive reusable and proven modules that are now part of every one of our production Servers. Having Servers built on the FactorySoft tool kit and our reusable modules allows us to rapidly deploy rock solid and highly advanced Servers.

DASTEC's currently offers design and development services for custom OPC Server as well as off the shelf OPC Server products. Our OPC development services have been used by major industrial equipment control and process control hardware manufactures and have been incorporated into production equipment sold by a major OEM. As end users become more and more accustom to using OPC, DASTEC's list of off the shelf Servers will grow rapidly as we leverage the more than fifty off the self communication products we current sell and maintain onto this technology.

DASTEC's OPC Server Design Concepts

The design of a good OPC Server is very similar to the design of any good communication driver or interface, foremost, high data throughput and then ease of configuration, quality diagnostic and debug information, and readable, understandable and informative documentation. DASTEC has over ten years of developing proven communication interfaces with these design goals.

Performance:

    All Servers are written using multithreaded concepts to fully take advantage of the protocol specifics of the devices and the communication media each Server supports. For example, Servers communicating over Ethernet are typically written with separate threads supporting each device. If a Server supports devices that support multiple outstanding requests then the Server will queue multiple request to those devices. DASTEC's years of industrial communication programming experience are reflected in the throughput optimizations that go into each Server design. You will not find faster OPC Servers.

Configuration:

      Throughput is not the only criteria in a well designed Server. DASTEC experiences in developing human interfaces for industrial processes and equipment is reflected in the graphical user interfaces of each Server's configuration environment. All Servers support a Window's Explorer look and feel with menu items, toolbars, device pane and tag pane views. The device pane is a tree like view similar to the Explorer's folder pane and the tag pane is a list of tags for the selected device, similar to the Explorer's file pane when in detail view mode. In some Servers, device program files can be imported to automatically generate the Server's tag data.

Diagnostics: When trouble is encountered, diagnosing the problem quickly and efficiently is important. DASTEC's technical support personal have had their input into the diagnostic features designed into these Servers. DASTEC has been supporting its communication driver and interface products since 1988. We know how to provide informative error data to help locate and correct problems. Diagnostic information is provided in several ways. Each device defined in a Server has at least two predefined tags that contain the latest error encountered with that device. One tag holds an error code and the other predefined tag an enunciated status message for the error code. By making this error information available via tags in the Server configuration, any client using the Server can access this information and the application using the client can log, alarm, notify or take any action deemed appropriate. Of coarse, the Servers also provide OPC quality information with each tag as well as result codes in the case of reads and writes. The Servers all support full enunciation calls for all result codes that they can set. All error codes and messages are fully detailed in the Servers' User Manual's including both explanation and corrective actions.

During configuration, pop up dialogs will present error information as data is entered to assist the developer in the configuration process. As with the runtime errors, all messages are fully explained in the User Manual of the Server.

In the rare cases when a call to DASTEC's technical support is required to diagnosis a communication or configuration problem, we have built into each Server the capability of opening debug windows which can be set to display various levels of debug messages to assist DASTEC's ability to quickly isolate and correct problems.