公共对象层管理网络服务对象，访问现场总线设备，元件层实现不同现场设备间的互操作。

Networks service object was managed, and the field bus equipments were visited with public target layer. The inter-operation among different equipments was realized with component layer.

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主要是提供现场层和应用软件间的纵向的数据集成和互操作。

OPC Data Access (DA) primarily provides vertical data integration and interoperability between measurement and automation systems on the manufacturing floor and client application.

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