Siemens SIMATIC ET 200AL - Page 874

OPC UA communication
9.3 Using the S7-1500 as an OPC UA server
Communication
188 Function Manual, 12/2017, A5E03735815-AF
Declaration of tags
Declare an instance of the instruction "OPC_UA_ServerMethodPost" and the tags with which
you supply the instruction parameters, see also Example program for providing a method for
OPC UA clients (Page 190).
The following points are important for the declaration:
● Create the instruction "OPC_UA_ServerMethodPost" as a multi-instance in the calling
function block.
Note
Name of the multiple instance
The multiple instance has to be named "OPC_UA_ServerMethodPost_Instance",
otherwise no method is created on the server.
Use drag-and-drop to move the instruction from the folder "Instructions > Communication
> OPC UA > OPC UA Server" to the editor. Next, click "Multi-instance".
● When the server method has one or more output parameters, you must declare a tag with
the name "
UAMethod_OutParameters
".
Start by creating a user-defined data type (UDT) for the output parameters of the server
method.
Then use this UDT for the tag "UAMethod_OutParameters".
In the example, the data type is called "UDT_OpenDoorOutArguments"; the only output
parameter is Result.
Alternative:
You can also assign the data type "Struct" to the tag "
UAMethod_OutParameters
". Then
create the components of this data type according to the output parameters of the server
method (same names and data types).
Figure 9-14 Declaration of tags