From The Classic Opc Interface To Opc Ua - Siemens SIMATIC ET 200AL System Manual

The security mechanisms are optional and configurable.
● Independence of a specific transport layer
The following transport mechanisms are currently supported by OPC UA:
– The transfer of messages as a binary stream directly via TCP/IP
– The transfer of messages with XML over TCP/IP and HTTP. This only allows a slow
Binary data exchange is supported by all OPC UA applications (required in OPC UA
specification).
● PLC tag mapping
The information from the OPC UA server (for example the PLC tags) is modeled as
nodes connected over references. This makes it possible to navigate from node to node
with an OPC UA client and find out what content can be read, monitored or written.
● Information
OPC UA servers provide a lot of information, for example about the CPU, the OPC UA
server itself, the data and the data types.
● Instance concept
OPC UA is based on a type instance concept. Both instances and their type definitions
are available in runtime.
● Differentiation of the functionality with profiles: S7-1500 supports the Embedded UA
Server Profile, for example
See also
Unified Automation (https://www.unified-automation.com)
OPC Foundation (https://opcfoundation.org)
9.1.4

From the Classic OPC interface to OPC UA

Standardized interface
Classic OPC only runs on Windows operating systems.
To get around this restriction, the OPC Foundation developed the OPC UA standard.
The standard is not platform-specific and uses an optimized, TCP-based binary protocol for
high-performance applications.
Different systems are therefore able to exchange data, for example:
● Controllers with MES and ERP systems
● Siemens controllers with controllers from other manufacturers
● Smartphones with controllers
● Embedded systems with controllers
● Smart sensors with controllers
Communication
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transfer and is therefore rarely used. It cannot be configured in STEP 7 and is not
supported by S7-1500 CPUs.
OPC UA communication
9.1 What you need to know about OPC UA
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