彩票走势图

XML DA

　　XML DA制定了一个非常简单的具有八个方法的web服务，这些方法能够处理所有的在OPC Data Access的应用程序中使用的典型功能。

XML DA的特点

• 易于实现
• 有限的功能，仅支持数据访问
• 覆盖了大多数OPC Data Access应用程序的要求
• 能够被用于安全通信的web服务扩展中
• 比基于COM的OPC要慢很多
• 产品可用

OPC UA

　　OPC UA的构成在它的基础框架中包含了所有的OPC规范中所需要的功能（Data Access, Alarms&Events, Historical Data, Batch, Commands, Security）。因此，OPC UA基础框架是复杂的并且它的设计使用到了一个网络数据库。而网络数据库本身非常复杂。由于难以实施和维护网络数据库模型，更简单的关系型数据库取而代之的被广泛使用。

　　Advosol 为XML-DA clients, XML-DA Servers 和Gateways提供的软件开发工具，它为新的应用程序和当前已使用的数千种OPC DA产品的轻松迁移路径提供了良好的基础。

XML-DA服务器端网关

　　XDAGW-SS网关能够使得从XML-DA客户端来访问OPC-DA服务器。使用该网关是最快速的方法使得现有的OPC DA服务器从远程的位置可访问。XDAGW-SS可以被配置为限制访问项的子集或仅允许读访问。

XML-DA客户端网关

　　XDAGW-CS网关允许OPC DA客户端访问XML-DA服务器。仅需要最小的配置。XDAGW-CS已测试通过兼容OPC DA V2.05和V3。该XML-DA Bridge由一对网关，XDAGW-SS网关和XDAGW-CS网关。现有的OPC DA客户端能够通过互联网访问OPC DA服务器。

OPC Exchange服务器

　　Exchange Server聚集来自多个OPC DA服务器的数据并在服务器之间交换数据。作为一个XML DA服务器被访问，该Exchange Server实际上作为一个网关为多个OPC DA服务器提供web服务。

XML-DA客户端组件

　　XMLDA.NET客户端组件允许XML-DA客户端直接访问本地OPC DA V2服务器，而不需要通过XML序列化，大大提高了性能。

　　客户端可以开发成为最先进的web服务客户端，即使需要访问OPC DA COM服务器。

XM-DA服务器工具包

　　网关能够被用于OPC DA服务器到XML-DA的包装，但是一个原生的XML-DA服务器能够提供更高性能和更好的配置选项。XDASrv Server Toolkit使得原生的XML-DA服务器的开发变得简单而快捷。通用的XML-DA服务器提供的服务是作为一个.Net的web服务。用户只需要开发一个具有少许几项的配置和设备访问方法的.Net程序集。还有一些可选的方法能够被实现用于优化性能和满足那些要求苛刻的应用程序。

OPC Historian WebService

　　XHDASrv OPC Historian Web Service以一个.NetWeb Service的方式暴露了一个OPC HAD服务器并且允许web客户端应用程序读取归档在OPC HAD服务器上的数据。

XML-DA实例客户端

　　一些XML-DA客户端所包含的源代码提供免费下载。

XML DA

XML DA specifies a rather simple web service with eight methods that handle all of the features typically used in the OPC Data Access applications.

XML DA Characteristics

• Simple to implement
• Limited functionality, Data Access only
• Covers the requirements of most OPC Data Access applications
• Can be used with web service extensions for secure communication
• Much slower than COM based OPC
• Products available

OPC UA

OPC UA is structured to have the required features for all OPC specifications (Data Access, Alarms&Events, Historical Data, Batch, Commands, Security) in it's base. Therefore the OPC UA base is complex and designed with a network database. A network database by itself is complicated. Due to the difficulty implementing and maintaining the network database model, the simpler relational databases are widely used instead

Advosol offers software development tools for XML-DA clients, XML-DA Servers and Gateways that provide a sound base for new applications and an easy migration path for the thousands of OPC DA products in use today.

XML-DA server-side Gateway

The XDAGW-SS gateway enables OPC-DA servers to be accessed from XML-DA clients. Using the gateway is the quickest way to make an existing OPC DA server accessible from a remote location.XDAGW-SS can be configured to restrict access to a item subset or allow only read access.

XML-DA client-side Gateway

The XDAGW-CS gateway allows OPC DA clients to access XML-DA servers. Only minimal configuration is required. XDAGW-CS is OPC DA V2.05 and V3 compliance tested.The XML-DA Bridge consists of a pair of gateways, the XDAGW-SS gateway and the XDAGW-CS gateway.Existing OPC DA clients can access OPC DA servers over the Internet.

OPC Exchange Server

The Exchange Server aggregates data from multiple OPC DA servers and exchanges data between these servers.Accessed as an XML DA server the Exchange Server acts as a gateway web service to multiple OPC DA servers.

XML-DA Client Component

The XMLDA.NET client component allows XML-DA clients to access local OPC DA V2 server directly, without going through XML serialization, offering highly improved performance.
Clients can be developed as state of the art web services clients even if OPC DA COM server need to be accessed.

XML-DA Server Toolkit

Gateways can be used to wrap OPC DA servers to XML-DA, but a native XML-DA server offers higher performance and better configuration options.The XDASrv Server Toolkit makes the development of native XML-DA servers simple an quick. The generic XML-DA server is provided as a .Net web service. The user only has to develop a .Net assembly with a few item configuration and device access methods. Optional methods can be implemented to optimize performance and realize demanding applications.

OPC Historian WebService

The XHDASrv OPC Historian Web Service exposes an OPC HDA server as a .Net Web Service and allows web client applications to read data archived in OPC HDA server.

XML-DA Sample Clients

A bundle of XML-DA Clients including source code can be downloaded free of charge.