It works!!! it looks like whatever change you made got rid of the "Host cannot be empty" error the customer was getting. Out of curiosity, would you mind sharing the issue that was generating that error?

We would appreciate it if you could please let us know when you are rolling this build-out so that we can do the same. Unless the build you provided me with is ready to be made public, in which case I would appreciate it if you could let me know if is ok with making this latest build public as well.

Many thanks for the assistance with this one.

Hello,

So unfortunately it looks like the OPC UA server is hosted on an HMI that is part of Filler equipment from a vendor named Kronos so he does not have direct access to the OPC UA server, unfortunately.

Now, do you happened to know of an OPC UA server that supports Method Calls capable of returning Complex Data? I was running my test incorrectly against OPC Router until I realized that OPC Router does not support Methods returning objects so I am not able to test if this an issue with his OPC UA server only or if this is happening with any OPC UA server that supports Methods returning Complex data.

If you have a test server in mind, we could try to test something simple where the server returns an object whenever the UA method is called. If this works, we should be able to ask the customer to try it on his end so that we can determine if this isolated to his Server only.

Hello,

I had the chance to talk to the customer and it looks like it will not be possible to expose the endpoint. The server is on a network that has no internet connection.

He also was able to do more testing and he found out that if he calls a method that only returns a single integer value, it works great. He gets back the integer with no errors.
he only gets the error I sent you before ("Host cannot be empty") when he calls a method that returns complex data.

he also implemented the DiscoverLocalEndpoints call in his test app to make sure he used an Endpoint that was sent from the Server itself, see below code. In this case, the Endpoint must be valid.

OpcLabs.EasyOpc.UA.Discovery.UADiscoveryElementCollection lEndpoints =
mClient.DiscoverLocalEndpoints("opc.tcp://10.97.219.220:4840/");
UAEndpointDescriptor endpointDescriptor = lEndpoints[0];
object[] lOutput = mClient.CallMethod(endpointDescriptor, "ns=2;s=MethodSet",
"ns=9;s=DMM.Messages.GetActiveMessages");

The error message indicates the Hostname must not be empty. Since he is getting the Endpoint from the host itself, the hostname is correct and not empty. Please see attached screen print of the EndPoint Descriptor.




So, it looks like the client can get to the server and call the methods just fine. It fails when the method returns complex data.
Also, I have used a generic client to do the method call and it returned and displayed the data correctly, so it is not an issue with the OPC Server side.

Do you have any other ideas on how to troubleshoot this behavior? Thank you for your support.

I just want to follow up with this. I was able to get the customer to upgrade to the latest version 5.60 but now the same code is yielding this error:

OpcLabs.EasyOpc.UA.OperationModel.UAException: An OPC-UA operation failure with error ID 'OpcLabs.UAEngine=1202' occurred, originating from '' and with depth of 1. The inner exception, of type "OpcLabs.EasyOpc.UA.Engine.UAEngineException", contains details about the problem. ---> OpcLabs.EasyOpc.UA.Engine.UAEngineException: Invalid opc.tcp discovery URL ("opc.tcp:"): The Host must not be empty.
+ The client method called (or event/callback invoked) was 'CallMultipleMethods'.
--- End of inner exception stack trace ---
at OpcLabs.EasyOpc.UA.OperationModel.UAException.CheckSuccess(Exception exception)
at OpcLabs.EasyOpc.UA.OperationModel.UAException.CheckSuccess(OperationResult operationResult)
at OpcLabs.EasyOpc.UA.IEasyUAClientExtension.CallMethod(IEasyUAClient client, UACallArguments callArguments)
at OpcLabs.EasyOpc.UA.IEasyUAClientExtension.CallMethod(IEasyUAClient client, UAEndpointDescriptor endpointDescriptor, UANodeDescriptor objectNodeDescriptor, UANodeDescriptor methodNodeDescriptor)
at TestOPCUAClient.Form1.btnGetAlarms_Click(Object sender, EventArgs e) in c:\TFS-TPW\KA - IMS Krones Alarmer\Main\TestOpcUAClientNewSDK\Form1.cs:line 62


Now, looking at the error description, it looks like the host is empty but it does not make any sense because the host is never empty as you will see in the code. Attached is the code that the customer is running. Please do let time know if you have any suggestions or questions.

Thank you for the reply. I had the customer tried with version 5.59 and he still gets the same issue where he gets back an array of objects and he is unable to cast to the UAGenericObject.

The Type of the object that is in the first index value of the Output is an array of Objects. The objects in this array are of type "UAExtensionObject", which only has binary data. (See screenshot)


He still is not able to cast any level of the returned objects to the UAGenericObject class, so he cannot see any of the returned complex data.

Do you have any other suggestions?