How to write the value of Opc Ua Node

Module Development
1

I’m looking the OPC UA Device example.The example show how to add Opc Ua Node.
But I have 2 question:
1.how to update the value of Opc Ua Node, is ManagedAddressSpaceServices.write(WriteContext context,List writeValues) ?
2.I try to update the value of one Opc Ua Node like this:
node.writeAttribute(
new AttributeContext(
node.getNodeContext().getServer(),
null
),
AttributeId.Value.uid(),
new DataValue(new Variant((long) 101), StatusCode.GOOD),
null
);
But the ig show err .“UaException: status=Bad_TypeMismatch, message=The value supplied for the attribute is not of the same type as the attribute’s value.”

2

You can call node.setValue() to update the value once, or install an AttributeFilter that will act as a callback any time an attribute is being read from the Node.

The device APIs are just a thin layer on top of the Eclipse Milo OPC UA SDK. You may find it useful to look at examples that use the API here and here.

1 Like
3

hi Kevin.
As you say,I try to install an AttributeFilter like:
{
node.setValue(new DataValue(new Variant(100 + i)));

            node.getFilterChain().addLast(
                new AttributeLoggingFilter(),
                AttributeFilters.getValue(
                    ctx ->
                        new DataValue(new Variant((long) new Random().nextInt()))
                )
            );
        }

but it run err :
java.lang.NoSuchMethodError: ‘org.eclipse.milo.opcua.sdk.server.nodes.filters.AttributeFilterChain org.eclipse.milo.opcua.sdk.server.nodes.UaVariableNode.getFilterChain()’

in pom.xml,I have add:

org.eclipse.milo
sdk-server
0.4.0

4

Ah, I forgot AttributeFilterchain is new to version 0.4. The SDK currently uses a 0.3.x version of Milo. There is something called AttributeDelegate instead. Look at the examples from one of the 0.3 release branches: https://github.com/eclipse/milo/blob/release/0.3.8/milo-examples/server-examples/src/main/java/org/eclipse/milo/examples/server/ExampleNamespace.java

You shouldn’t add your own Milo dependency - you get one as a transitive dependency from the module SDK.

5

I done it. Thanks for your support.