OPC UA communication
9.1 What you need to know about OPC UA
Communication
130 Function Manual, 11/2019, A5E03735815-AH
9.1.3 OPC UA for S7-1200/S7-1500 CPUs
In OPC UA, one system operates as a server and provides data the existing information to
other systems (clients).
OPC UA clients, for example, have read and write access to data on an OPC UA server.
OPC UA clients call methods on the OPC UA server.
You can access this data online with a client, including e.g. information on performance and
diagnostics. In OPC UA terminology, this function is called "Browsen". The "Subscription"
function eliminates regular reading of a tag; with this function, the server informs a client
about value changes.
A system can be both a client and a server at the same time.
OPC UA server of the S7-1500 CPU
As of firmware version 2.0, an S7-1500 CPU is equipped with an OPC UA server.
The following sections describe how you configure the OPC UA server of the S7-1500 CPU
to make data and methods available for OPC UA clients so that clients have read or write
access to PLC tags on the CPU and can call server methods.
The following sections also set out how to integrate companion specifications into the
address space of the OPC UA server.
OPC UA server of the S7-1200 CPU
As of firmware V4.4, an S7-1200 CPU is equipped with an OPC UA server.
The OPC UA server is generally configured as it is for an S7-1500 CPU; the scope of
functions and the quantity limits are limited according to the supported "Micro Embedded
Device 2017 Server Profile". Unlike for an S7-1500 CPU, the following functions are
not
available:
● Server methods
● Structured data type (structures and arrays)
● Registered Read and Registered Write
You can find additional information in the STEP 7 online help.
OPC UA client of the S7-1500 CPU
As of firmware version V2.6, an S7-1500 CPU is additionally equipped with an OPC UA
client.
The following sections show how to use standardized instructions (PLCopen function blocks)
to create a user program that, as an OPC UA client, provides the following functions:
● Reading data from an OPC UA server
● Writing data to an OPC UA server
● Calling methods of an OPC UA server
STEP 7 (TIA Portal) assists you in creating user programs by providing an editor for client
interfaces and a parameter assignment for OPC UA connections.
The OPC UA instructions for an S7-1500 CPU as client are described in detail in the help to
the instructions (Instructions > Communication > OPC UA).
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