My VBScript example: "OpcLabs.EasyOpc.UA.Services.IEasyUAClientConnectionControl, OpcLabs.EasyOpcUA" Your VBA code: "OPCLabs.EasyOpc.UA.Services.IEasyUAClientConnectionControl, OpcLabs.EasyOpcUA"

'****************************************************** 'Implementation of all OPC UA Client functions used to read 'and write to the PLC OPC UA server (typically via a Softing UA Server Module) '****************************************************** Option Explicit Option Base 1 Dim action As Variant Dim scrap As Variant Public UaConnected As Boolean Private isg_OpcUaClient As EasyUAClient ' OPC Labs Easy OPC UA Client Private isg_UaClientConnectionControl As ComEasyUAClientConnectionControl 'used to lock connection to ua server while workbook is in open Private isg_LockHandle As Long 'reference to OPC UA lock handle used to close connection later Private opcUaServerURL As String Private opcUaNamespace As String Public Sub ua_ConnectToUaServer() On Error GoTo ua_ConnectError If UaConnected = False Then If Not isg_OpcUaClient Is Nothing Then 'first disconnect existing instance UaConnected = False Call opc_ua.ua_DisconnectFromUaServer End If 'set connection info from matrix registration worksheet opcUaServerURL = ActiveWorkbook.Sheets("MatrixReg").Range("PLC_UA_URL").value opcUaNamespace = ActiveWorkbook.Sheets("MatrixReg").Range("PLC_UA_NameSpace").value 'create instance and set client connection control lock Set isg_OpcUaClient = New EasyUAClient Set isg_UaClientConnectionControl = isg_OpcUaClient.GetServiceByName("OPCLabs.EasyOpc.UA.Services.IEasyUAClientConnectionControl, OpcLabs.EasyOpcUA") isg_LockHandle = isg_UaClientConnectionControl.LockConnection(opcUaServerURL) 'issue an initial read to a generic tag to trigger the connection to the UA Server to open and lock a connection to the endpoint scrap = isg_OpcUaClient.ReadValue(opcUaServerURL, "ns=" & opcUaNamespace & ";s=" & OPC_UA_TAGPREFIX & "DIConfig[0].delay") UaConnected = True Exit Sub End If ua_ConnectError: action = ErrorHandler(Err) Select Case action Case RESUME_STATEMENT Resume Case RESUME_NEXT Resume Next Case UNRECOVERABLE Call opc_ua.ua_DisconnectFromUaServer Application.DisplayAlerts = True End Case Else scrap = MsgBox("Critical Error #" & Format(Err) & Chr(13) & Chr(10) & _ "Error Message: " & Error(Err), vbOKOnly, "Unhandled OPC UA Exception") Call opc_ua.ua_DisconnectFromUaServer Application.DisplayAlerts = True End End Select End Sub Public Sub ua_DisconnectFromUaServer() On Error Resume Next If Not Workbooks("ISGProgramTool.xlam").Sheets("OPC_UA_VBA").isg_OpcUaClient Is Nothing Then isg_UaClientConnectionControl.UnlockConnection (isg_LockHandle) Set isg_OpcUaClient = Nothing UaConnected = False End If End Sub

Rem This example shows how to lock and unlock connections to an OPC UA server. The component attempts to keep the locked Rem connections open, until unlocked. Option Explicit Dim endpointDescriptorUrlString: endpointDescriptorUrlString = "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer" Dim EndpointDescriptor: Set EndpointDescriptor = CreateObject("OpcLabs.EasyOpc.UA.UAEndpointDescriptor") EndpointDescriptor.UrlString = endpointDescriptorUrlString ' Instantiate the client object. Dim Client: Set Client = CreateObject("OpcLabs.EasyOpc.UA.EasyUAClient") ' Obtain the client connection monitoring service. Dim ClientConnectionMonitoring: Set ClientConnectionMonitoring = Client.GetServiceByName("OpcLabs.EasyOpc.UA.Services.IEasyUAClientConnectionMonitoring, OpcLabs.EasyOpcUA") If ClientConnectionMonitoring Is Nothing Then WScript.Echo "The client connection monitoring service is not available." WScript.Quit End If ' Obtain the client connection control service. Dim ClientConnectionControl: Set ClientConnectionControl = Client.GetServiceByName("OpcLabs.EasyOpc.UA.Services.IEasyUAClientConnectionControl, OpcLabs.EasyOpcUA") If ClientConnectionControl Is Nothing Then WScript.Echo "The client connection control service is not available." WScript.Quit End If ' Display the server condition changed events. WScript.ConnectObject ClientConnectionMonitoring, "ClientConnectionMonitoring_" WScript.Echo "Reading (1)" ' The first read will cause a connection to the server. Dim AttributeData1: Set AttributeData1 = Client.Read(endpointDescriptorUrlString, "nsu=http://test.org/UA/Data/ ;i=10853") WScript.Echo AttributeData1 WScript.Echo "Waiting for 10 seconds..." ' Since the connection is now not used for some time, and it is not locked, it will be closed. WScript.Sleep 10*1000 WScript.Echo "Locking..." ' Locking the connection causes it to open, if possible. Dim lockHandle: lockHandle = clientConnectionControl.LockConnection(EndpointDescriptor) WScript.Echo "Waiting for 10 seconds..." ' The connection is locked, it will not be closed now. WScript.Sleep 10*1000 WScript.Echo "Reading (2)" ' The second read, because it closely follows the first one, will reuse the connection that is already open. Dim AttributeData2: Set AttributeData2 = Client.Read(endpointDescriptorUrlString, "nsu=http://test.org/UA/Data/ ;i=10853") WScript.Echo AttributeData2 WScript.Echo "Waiting for 10 seconds..." ' The connection is still locked, it will not be closed now. WScript.Sleep 10*1000 WScript.Echo "Unlocking..." clientConnectionControl.UnlockConnection(lockHandle) WScript.Echo "Waiting for 10 seconds..." ' After some delay, the connection will be closed, because there are no subscriptions to the server and no ' connection locks. WScript.Sleep 10*1000 WScript.Echo "Finished." Sub ClientConnectionMonitoring_ServerConditionChanged(Sender, e) WScript.Echo e End Sub ' Example output: ' 'Reading (1) '"opc.tcp://opcua.demo-this.com:51210/UA/SampleServer" Connecting; Success; Attempt #1 '"opc.tcp://opcua.demo-this.com:51210/UA/SampleServer" Connected; Success '-1.034588E+18 {Single} @2021-11-15T15:26:39.169 @@2021-11-15T15:26:39.169; Good 'Waiting for 10 seconds... '"opc.tcp://opcua.demo-this.com:51210/UA/SampleServer" Disconnecting; Success '"opc.tcp://opcua.demo-this.com:51210/UA/SampleServer" Disconnected(RetrialDelay=Infinite); Success 'Locking '"opc.tcp://opcua.demo-this.com:51210/UA/SampleServer" Connecting; Success; Attempt #1 '"opc.tcp://opcua.demo-this.com:51210/UA/SampleServer" Connected; Success 'Waiting for 10 seconds... 'Reading (2) '2.288872E+21 {Single} @2021-11-15T15:26:59.836 @@2021-11-15T15:26:59.836; Good 'Waiting for 10 seconds... 'Unlocking 'Waiting for 10 seconds... '"opc.tcp://opcua.demo-this.com:51210/UA/SampleServer" Disconnecting; Success '"opc.tcp://opcua.demo-this.com:51210/UA/SampleServer" Disconnected(RetrialDelay=Infinite); Success 'Finished.

' Obtain the client connection control service. Dim ClientConnectionControl: Set ClientConnectionControl = Client.GetServiceByName("OpcLabs.EasyOpc.UA.Services.IEasyUAClientConnectionControl, OpcLabs.EasyOpcUA")

' Locking the connection causes it to open, if possible. Dim lockHandle: lockHandle = ClientConnectionControl.LockConnection(EndpointDescriptor)

ClientConnectionControl.UnlockConnection(lockHandle)