Error Writing OPC-UA Node

Module Development
1

I am trying to write a tag that references a ManagedDevice implementation using the Milo OPC-UA driver.

The following is the error that the designer throws at me:

Error writing to InterMessageDelay.value: Bad("Bad_InternalError: An internal error occurred as a result of a programming or configuration error.")

The following is the snipped of my code that implements the write AttributeFilter:

UaVariableNode interMessageDelaysNode = UaVariableNode.builder(getNodeContext())
                .setNodeId(deviceContext.nodeId(String.format("%s/InterMessageDelay",folderName)))
                .setBrowseName(deviceContext.qualifiedName("InterMessageDelay"))
                .setDisplayName(new LocalizedText("InterMessageDelay"))
                .setDataType(BuiltinDataType.UInt32.getNodeId())
                .setTypeDefinition(Identifiers.BaseDataVariableType)
                .setAccessLevel(AccessLevel.READ_WRITE)
                .setUserAccessLevel(AccessLevel.READ_WRITE)
                .build();
        interMessageDelaysNode.setValue(new DataValue((new Variant(0))));
        interMessageDelaysNode.getFilterChain().addLast(AttributeFilters.getValue(
                getAttributeContext ->
                        new DataValue(new Variant(snmpDevice.getInterMessageDelay()))
                )
        );
        interMessageDelaysNode.getFilterChain().addLast(AttributeFilters.setValue((ctx, value) -> {
            snmpDevice.setInterMessageDelay((Integer) value.getValue().getValue());
            ctx.setAttribute(AttributeId.Value, value);
        }));
        getNodeManager().addNode(interMessageDelaysNode);
        folderNode.addOrganizes(interMessageDelaysNode);

Thanks,
Brandon

2

This line is probably causing a ClassCastException to be thrown and not caught by your code. You set the DataType to UInt32, so you should expect a org.eclipse.milo.opcua.stack.core.types.builtin.unsigned.UInteger value.

3

Thank you for the quick response!

Here is the method signature inside my SNMPDevice class:

public void setInterMessageDelay(int interMessageDelay){ this.interMessageDelay = interMessageDelay; }

What is the correct way to pass only the value that is contained in DataType to this method?

4

Easiest thing to do would be just change the DataType of your “InterMessageDelay” VariableNode to BuiltinDataType.Int32.

5

That would work except I’m using that variable to call sleep which takes a long as it’s input. So ultimately I will need this value to be a basic Java type.

6

Thanks again Kevin.

I found that UInteger has a intValue method and I changed my setValue filter to the following:

interMessageDelaysNode.getFilterChain().addLast(AttributeFilters.setValue((ctx, value) -> {
            UInteger uInteger = (UInteger) value.getValue().getValue();
            snmpDevice.setInterMessageDelay(uInteger.intValue());

            ctx.setAttribute(AttributeId.Value, value);
        }));
7

For anyone happening across this, I was seeing the same error message on a bulk write in one of my gateway scripts.

It was occurring because one of the tag values I was reading and then trying to write to another tag was of value 'null'.