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-Classic in .NET
  7. Reading, Writing, Subscriptions, Property Access
  9. Writing value and timestamp to OPC DA 2.05a

Writing value and timestamp to OPC DA 2.05a

More
27 Feb 2024 16:40 #12594 by support
Replied by support on topic Writing value and timestamp to OPC DA 2.05a
Hello.

OPC DA 1.0 and 2.0x can only write the value. That would be "WriteItemValue" method in QuickOPC.

With OPC DA 3.0, you can also write value+timestamp+quality.

There is nothing in between (just value+timestamp). Or, the server may decide to it over OPC DA 3.0,m with ignoring the quality. But, you cannot do it with OPC DA 1.0 or 2.0x, there is just no such thing in these specs.

Best regards

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

More
27 Feb 2024 16:06 #12592 by ScottEwine
Writing value and timestamp to OPC DA 2.05a was created by ScottEwine
I am trying to write data to a PI server that supports 2.05a, I am using the following code snippet:

DAVtq dAVtq = new DAVtq();
EasyDAClient easyDAClient1 = new EasyDAClient();

try
{

dAVtq.Value = value;
dAVtq.Quality = 192;
dAVtq.Timestamp = dateTime.ToUniversalTime();

easyDAClient1.WriteItem(MachineName, ServerName, ItemID, dAVtq);

It works well in my test environment writing to a simulation server, but at the customer it gives the error below.

No read item or write item function available. The OPC server does not contain a function that can satisfy the combination of requirements (execution method and data source). For example, there is no way to read asynchronously from the OPC Cache if the server only supports OPC-DA 2.0. Also, you cannot write a value-quality-timestamp triple using OPC-DA 1.0 or 2.0.

I understand what the error is saying, and the customer is working to upgrade to support DA 3.0, but if quality is not important, what is the syntax I can use to just write the value and timestamp?

Thanks, Scott

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

Moderators: support
  1. Forum
  3. Discussions
  5. QuickOPC-Classic in .NET
  7. Reading, Writing, Subscriptions, Property Access
  9. Writing value and timestamp to OPC DA 2.05a
Time to create page: 0.046 seconds