Hello,

I'm trying out the OPC library for integrating with an industrial machine. I use VisualFoxPro as a language with the trial version and for testing purposes, with the prospect of purchasing the full license.
During my tests, I managed to connect to my own virtual machine using the 'easyuaclientform' example present in the folder of the examples proposed by you and verifying the nodes on the other side with the OPCExpert tool.
I can easily acquire the data of the nodes in reading but, I don't know why, I have difficulty trying to write some value on some node (I think due to syntax problems or in my practices).
I tried different methods like 'WriteValue' or 'WriteValueEx', integrating them in your example. However I always get errors 0x8002000e or 0x80020006.

After various attempts, I suspect that something is wrong in the configuration, or that the free version doesn't allow me to work in writing...

I would like to make sure I can both read and write to a node of an OPC server to continue the tests and purchase the license...

I'm here to ask for help precisely because I would like to understand the functioning of the processes... for example, how could I modify your example so that I can write to an OPC node?
What is the best way to do a basic test?
Based on the code I share, does this seem right as an approach?

I put '00000' as a port number for sample purpose (to keep it private) and I got the error in runtime after the orange line.

Thanks for any help and support
GiacoF

DECLARE INTEGER GetTickCount IN kernel32



THISFORM.OutputEdit.Value = ""



* Instantiate the client object.

oClient = CREATEOBJECT("OpcLabs.EasyOpc.UA.EasyUAClient")



* In order to use event pull, you must set a non-zero queue capacity upfront.

oClient.PullDataChangeNotificationQueueCapacity = 1000



THISFORM.OutputEdit.Value = THISFORM.OutputEdit.Value + "Subscribing..." + CHR(13) + CHR(10)



* Specify the OPC server item you want to subscribe to

cSubscriptionItemID = "i=15183"



oSubscription = oClient.SubscribeDataChange("opc.tcp://vm-sviluppo:00000/opcexpert", "nsu=http://opcfoundation.org/UA/;i=15183", 1000)



THISFORM.OutputEdit.Value = THISFORM.OutputEdit.Value + "Processing data change notification events for 1 minute..." + CHR(13) + CHR(10)



EndTick = GetTickCount() + 60000

DO WHILE GetTickCount() < EndTick

oEventArgs = oClient.PullDataChangeNotification(2*1000)

IF NOT ISNULL(oEventArgs)

THISFORM.OutputEdit.Value = THISFORM.OutputEdit.Value + oEventArgs.DisplayString + CHR(13) + CHR(10)

ENDIF

ENDDO



LOCAL cItemId, nValueToWrite



* Writing to OPC server after connection

THISFORM.OutputEdit.Value = THISFORM.OutputEdit.Value + "Writing to OPC server..." + CHR(13) + CHR(10)



* Specify the OPC server item you want to write to

cWriteItemID = "i=15183"

cValueToWrite = "Hello"



* Write the value to the OPC server item as a string value

oWriteResult = oClient.WriteValue("opc.tcp://vm-sviluppo:57888/opcexpert", cWriteItemID, cValueToWrite, "String")



IF oWriteResult.Succeeded

THISFORM.OutputEdit.Value = THISFORM.OutputEdit.Value + "Write succeeded." + CHR(13) + CHR(10)

ELSE

THISFORM.OutputEdit.Value = THISFORM.OutputEdit.Value + "Write failed: " + oWriteResult.Exception + CHR(13) + CHR(10)

ENDIF



THISFORM.OutputEdit.Value = THISFORM.OutputEdit.Value + "Unsubscribing..." + CHR(13) + CHR(10)

oSubscription.Unsubscribe()



THISFORM.OutputEdit.Value = THISFORM.OutputEdit.Value + "Finished." + CHR(13) + CHR(10)