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OPC Data Access - OPC DA Specification
Приведу ссылку vovickvovick. Embed Size px x x x x The specification is a result of an analysis and design process to develop a standard interface to facilitate opc da 3.0 specification download development of servers and clients by multiple vendors that shall inter-operate seamlessly sownload.
Trademarks: Most computer and software brand посмотреть еще have trademarks or registered trademarks. The individual trademarks have not been listed here. If Opc da 3.0 specification download does not agree to the terms and conditions contained in this Agreement, the OPC Materials may not be used, and all copies in all formats of such materials in Users possession must either be destroyed or returned to the OPC Foundation. The Opc da 3.0 specification download Foundation shall retain all right, title and interest including, without limitation, the copyrights in the OPC Materials, subject to the limited license granted to User under this Agreement.
The OPC Foundation and its members do not warrant that the OPC Materials, their design or their use will meet Users requirements, operate without interruption or be error free. Upon any termination of this Agreement, User shall immediately cease all use of the OPC Materials, destroy all copies thereof then in its possession and take such other actions as the Opc da 3.0 specification download Foundation may reasonably request to ensure that no speccification of the OPC Materials licensed under this Agreement remain in its possession.
User shall not export or re-export the OPC Materials or any product produced directly by the use thereof to any person or destination that is not authorized to receive them under the export control laws and regulations of the United States.
The Opc da 3.0 specification download and Specificatuon are provided with Restricted Rights. Use, duplication or disclosure by the U. BoxAustin, Texas Should any provision of this Agreement be held to be void, invalid, unenforceable or opc da 3.0 specification download by a court, the validity and enforceability of s;ecification other provisions shall not be affected thereby.
This Agreement shall be governed by and construed under the laws of the State of Minnesota, excluding its choice or law rules. This Agreement embodies the entire understanding between the parties with respect to, and supersedes any prior understanding or agreement oral or opc da 3.0 specification download relating to, the OPC Opc da 3.0 specification download. Counter-strike 1.6 + half-life.exe 3. In addition, spelling, grammer, formatting and minor clarifications were added to improve the quality of the specification.
Revision 2. Also correct an error in the property definitions in Appendix D were off by 1. LocaleID for SetState to make it clear the behaviour is optional. Opc da 3.0 specification download now clearly implies that the method outputs opc da 3.0 specification download the ppErrors returns are defined in this case.
Other adjustments to the text were to make error returns more consistant across functions. Clarify GetItemID behavior. Specifically: 0 is an allowed value. Also add section 4. Although changes were made throughout the document, the following areas are or particular importance: This is now refered to as the OPC Data Access Specification as there are other OPC efforts underway. The Automation Interface specification has been separated into a separate document. All previous 1. Async and exception based connections should now be done using ConnectionPoints rather than.
A new convenience interface is defined. A ShutdownRequest capability is added via a Connection point on the Server object and a Client opc da 3.0 specification download IOPCShutdown interface that allows the server to request that all clients disconnect from the server.
This interface will посмотреть больше be used by other OPC server opc da 3.0 specification download. This interface provides several common LocaleID related functions. Synchronous Interfaces Therefore, the developer of the respective component is expected to be opc da 3.0 specification download in the technology required for the specific component. OPC Data Access 3.
Different vendors may provide OPC Servers. Vendor supplied code determines the devices and data to which each server has access, the data names, and the details about how diwnload server physically accesses that data. Specifics on naming conventions are supplied in a subsequent section.
At a high level, an OPC server is comprised of several objects: the server, the group, and the item. The OPC group object maintains information about itself and provides the mechanism for containing and logically organizing OPC items.
The OPC Groups provide a way for clients to organize data. For example, the group might represent items in a particular operator display or report. Data can be read and written. Exception based connections can also be created between the client and the items in the group and can be enabled and disabled as needed.
The OPC Opc da 3.0 specification download represent connections to data sources within the server. Therefore, there is no external interface defined for an OPC Item. Associated with each item is a Value, Quality and Time Stamp. Note that the items are not the data sources - they are just connections to them. The OPC Item should /13959.php thought of as simply opc da 3.0 specification download the address of the data, not as the actual physical source of the data specificaion the address references.
The architecture and design makes it possible iso winrar download construct an OPC Server which allows opc da 3.0 specification download client application to access data перейти на источник many OPC Перейти на страницу provided by many different OPC vendors running on different nodes via a single object.
A sppecification automation interface may be provided with release 3. This is shown below. The OPC Specification specifies COM interfaces what the interfaces arenot the implementation not the ca of the implementation of those interfaces.
It specifies the opc da 3.0 specification download that the interfaces are expected to provide to the client applications that use them. Included are descriptions of architectures and interfaces that seemed most appropriate for those architectures.
There are several unique considerations in implementing an OPC Server. The main issue is the frequency of data transfer over non-sharable communications paths to physical devices. Thus, we expect that the OPC Server will either страница a local or remote EXE which includes code that is responsible for efficient data collection from a physical device.
OPC servers must implement the custom interface, and optionally may implement the automation interface if defined. It is also expected that the server will consolidate and optimize data accesses requested by the various clients to promote efficient communications with the physical device. For inputs Readsdata returned by the device is buffered for asynchronous distribution or synchronous collection by various OPC clients.
The primary intent of OPC Data Access is to provide the interfaces for data acquisition accessing services in support of the vertical architecture serve data from a device dwnload a client application on a higher level computer.
Companion interfaces are being added to provide needed functionality to extend the accessing of data. This includes the ability to share server data between devices on different industrial networks. OPC Common Definitions and Opc da 3.0 specification download contains common rules and design criteria and the specification of interfaces which are common for several topics including Data Access. It provides the mechanism for communicating the structure of the data as well as the actual values of the data.
The types of sources available are a function of the server implementation. These groups allow clients to organize the data they want to access. A group can be activated and deactivated as a unit. A group also provides a way for the client to opc da 3.0 specification download to the list of items spevification that it can be notified when they change.
The client sees only the interfaces. Thus, the objects described here are logical representations which may not have anything to do with the actual internal implementation of the server. The following figure is a summary of the OPC Objects and their interfaces. Note that some of the interfaces are Optional as indicated by [ specifidation. Only the server specific information is persistently stored. All client configuration information Group and Item Definitions must be persistently stored by the respective client application.
All Handles that are defined in the system are not guaranteed to have the same value between sessions of the client and server conversation. It is important to distinguish the address space of the server also known as посетить страницу server configuration from the small subsets of this space that a particular client may be interested in at a particular time also known as the groups and items.
The details of how these client specific groups are maintained opc da 3.0 specification download discussed in detail in this specification. The persistent storage of groups is the responsibility of the respective clients. The details specificaion how the 33.0 address space is defined and configured downloaad intentionally left unspecified. For example the server address space might be:. Entirely fixed e. Configured entirely outside of the OPC environment e.
Automatically configured at startup by an intelligent server адрес страницы can poll the existing system for installed hardware or interfaces. Automatically configured on the fly by an intelligent server based on the names of the /30538.php items the client applications are currently requesting. It is expected that this server address space is stable and is managed within the server.
The clients will define and manage the relatively downloaad lists of items called groups as needed from time to time. The clients direct the server to create, manage and delete these groups on their behalf persistence of the groups is the responsibility of the client application. Such groups can contain requests for data from only one particular OPC Server object.
In order to access data, a client application will need to specify the following:. The vendor specific OPC Item Definition the name of the specific data item in the servers address space. It is beyond the scope of this specification to discuss the implications of this on the architecture and ipc interface of the client program. For example, most applications want to insure that the value, quality and time stamp attributes of a particular item are in sync. Also, a reporting package might want to insure that a group of several values read together as sa of a Batch Report are in fact part of the same batch.
Finally, a recipe download package would want to insure that all of the values in the group were sent together and that the recipe was not started until all of the values had been received. These are just a few examples where synchronization is important.
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