Professional OPC
Development Tools

logos

lupa

Online Forums

Technical support is provided through Support Forums below. Anybody can view them; you need to Register/Login to our site (see links in upper right corner) in order to Post questions. You do not have to be a licensed user of our product.

Please read Rules for forum posts before reporting your issue or asking a question. OPC Labs team is actively monitoring the forums, and replies as soon as possible. Various technical information can also be found in our Knowledge Base. For your convenience, we have also assembled a Frequently Asked Questions page.

Do not use the Contact page for technical issues.

  1. Forum
  3. Discussions
  5. QuickOPC-UA in .NET
  7. Reading, Writing, Subscriptions
  9. Is WriteValue guaranteed to succeed?

Is WriteValue guaranteed to succeed?

More
28 Sep 2015 14:17 #3577 by support
Replied by support on topic Is WriteValue guaranteed to succeed?
If there is a problem with writing, either reported by the server or detected by the client, the EasyUAClient.WriteValue should throw an exception (OpcLabs.EasyOpc.UA.OperationModel.UAException, actually).

If you make this call but the value does not change in the server, then I can think of following possible causes:

1) A problem in the server - it does not actually perform the write, but does not return an error to the client,

2) A bug in the client: it receives an error indication from the server, but does not throw the UAException as it should.

3) The UAException is thrown but your program catches it and "swallows" it silently (not likely but still a possibility).

Best regards

Please Log in or Create an account to join the conversation.

More
28 Sep 2015 12:25 #3576 by bardhustveit@gmail.com
Is WriteValue guaranteed to succeed? was created by bardhustveit@gmail.com
Hi, I have an problem at a client site that I'm trying to isolate.

I have subscribed to about 30 alias on a KepWareEx server.
I write to on alias with WriteValue("url", "id", object), I will then get a value changed event from the subscription.

But in some very few cases the value is not changed on the server (and I don't get a value changed event, as expected if the value isn't changed).

Is the WriteValue guaranteed to succeed? Or is there some cases where it will fail to update the value in the PLC but not generate an error?

Regards
Bard Hustveit

Please Log in or Create an account to join the conversation.

Moderators: support
  1. Forum
  3. Discussions
  5. QuickOPC-UA in .NET
  7. Reading, Writing, Subscriptions
  9. Is WriteValue guaranteed to succeed?
Time to create page: 0.041 seconds