Siemens SIMATIC ET 200AL, System Manual

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OPC UA communication
9.3 Using the S7-1500 as an OPC UA server
Communication
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A Call of the server method and management of the "Done" information (method complete)
① Asynchronous call of the server method
② Asynchronous "Done" information for the method called (method complete)
B Wait for OPC UA client calls, management of calls in the queue, forwarding of "Done" information from the cyclic
user program to the OPC UA client
③ Data transfer from the OPC UA server to the method instances of the user program and vice versa
C Check whether method has been called.
If it has, forwarding of input data from the OPC UA server to the method instance of the user program and feedback
to the method instance that the method has been called ("called")
④ Synchronous call of the instruction OPC_UA_ServerMethodPre as a multi-instance stating the storage area for the
input data from the OPC UA server.
The return value indicates whether or not the method has been called by the OPC UA client.
⑤ Check whether the method has been completed or is still active ("busy").
D Check whether the method has been completed.
If it has, the output data of the method instance is forwarded to the OPC UA server and the method instance is
notified that the method has been completed. The OPC UA server is notified.
⑥ Call of the method FB (in this case: FB Cool) with the required instance and the process parameters
Figure 9-49 Example: Calling the "Cool" server method
Information about server instructions
The "OPC_UA_ServerMethodPre" and "OPC_UA_ServerMethodPost" are described in detail in
the help to the Instructions > Communication > OPC UA > OPC UA server.
See also
Boundary conditions for using server methods (Page 283)