Problem with read DataType

[AppleCitron]

Hello there, I'm having some issues with my Milo and was hoping you could help me out.
The code snippet below is requesting the DataTypes of NodeId List.
When I request a certain DataType from the Client to the Server, I receive a response in VariantType. Upon checking with the Server, it seems that the Node's DataType is set as UInt32.
Other types are being read correctly, but I'm receiving incorrect responses for some Types and would like your assistance. Also, I was wondering how I should go about setting the first argument, maxAge, in the read function?

for (String localTagListKey : localTagList.keySet()) {
readNodeIds.add(localTagList.get(localTagListKey).createNodeId());
}

List dataValues = client.read(0.0, TimestampsToReturn.Both, readNodeIds, Collections.nCopies(readNodeIds.size(), AttributeId.DataType.uid())).get();

[kevinherron]

I think what you're seeing is that the server has set the DataType of these Nodes to Variant, which means it can be any type. When you read the Value you'll naturally get a value of some type.

Max age of 0.0 is almost always correct - it means the current value without any caching. Most servers do not actually implement max age anyway.

[AppleCitron]

I checked the same phenomenon in UA Expert. I will contact the Server for this part.

Is there any other way to deal with the dataType part I asked earlier? As a result of checking UaExpert, the data type is UInt32.

OPC Server dataType: UInt32
UA Expert check: UInt32
Milo Client: Variant

Milo reads different data types, and I need help on how to get UInt32 from Milo.

[kevinherron]

I'm not sure why Milo would read a different DataType. Wireshark would be useful for this as well. Make sure there is no security on the connection while you capture.

[kevinherron]

@AppleCitron did you ever get captures?

Are you aware that all values come wrapped in a Variant when you read them, and that maybe you just needed to look inside the Variant to find the NodeId value in this case?

[AppleCitron]

Thank you for asking again. The Value didn't cause any problem. The problem was that the DataType came differently, and we are checking if there's a problem with the OPC Server. When Milo needs confirmation, I will try capturing using Wireshark.

[kevinherron]

ReadResponse response = client.read(
    0.0,
    TimestampsToReturn.Neither,
    List.of(
        new ReadValueId(
            NodeIds.Server_ServerStatus_CurrentTime,
            AttributeId.DataType.uid(),
            null,
            QualifiedName.NULL_VALUE)));

DataValue value = response.getResults()[0];
Variant variant = value.getValue();
NodeId dataTypeId = (NodeId) variant.getValue();

System.out.println("DataTypeId=" + dataTypeId.toParseableString());