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.
- Forum
- Discussions
- QuickOPC-Classic in .NET
- Connections, Reconnections, COM/DCOM
- OPC XML-DA. Communication problem
OPC XML-DA. Communication problem
Note: Both of your posts contained forward slash, no backward slash.
But anyway, I do not think there is anything to be solved on our side. Each HTTP request contains the URL used. We are sending the URL to the server precisely as it is entered into the system (e.g. what you type in Connectivity Explorer, or what you pass in the code through the QuickOPC API). You have verified that "the hard way" by finding the difference between having and not having the slash at the end, and I have verified it today by testing various URLs and observing the communication in the network analyzer.
It is the responsibility of the server to provide URLs that work, and your responsibility to use the right ones when connecting to the server. If the right ones are those with slash at the end, then you need to use them.
I do not know whether you have used the trailing slash with your dOPC Explorer tests. if you did, then it's clear. if you have not, and it still worked, then it is possible that the dOPC Explorer has added the slash by itself, but in such case it is not doing it quite right.
Best regards
Please Log in or Create an account to join the conversation.
It also works when url end up with forward slash:
http://172.17.115.68:6010/
Please Log in or Create an account to join the conversation.
Sorry for the delay in replying. I've found the way how to connect to OPC XML-DA server
It works with url opc.xmlda://172.17.115.68:6010/ (backslash is required)
I have wireshark tracing file of "dOPC Connect" call, "ConnectivityExplorer TCP Connect Test" and "ConnectivityExplorer Connect" when url is valid
I haven't seen requests nor responses when url starts from 'html' or 'opc.xmlda' without trailing backslash, at least on port 6010
I can send them if you are still interested in them
Best regards
Please Log in or Create an account to join the conversation.
Thank you
Please Log in or Create an account to join the conversation.
TCP Connection Test does not send any request *inside* the TCP stream. It simply attempts to opens the socket, and the closes it if opening has succeeded.
I spoke with the developer. The current plan is that we will allow the GetStatus call be disabled also for XML-DA. We will also try to analyze what dOPC Explorer does - the hypothesis being that it does *not* call GetStatus. I will post here when I have more (allow some days).
Best regards
Please Log in or Create an account to join the conversation.
You are right, the TCP Connection Test succeeded. I'm curious why Wireshark didn't trace any answer. if Connectivity Explorer sent some request I would see an answer
Best regards
Please Log in or Create an account to join the conversation.
If you are referring to "TCP Connection Test" in Connectivity Explorer, then all it does is it tries to establish a TCP connection to the given host/port, and then it closes it. It does not attempt to issue any kind of request to the server. It meant to test for common error cases like "computer not running", "Server not running", "Incorrect port used", or "firewall blocks the port". I assume that the TCP Connection Test actually succeeded, is that correct? If so, any response from the server is irrelevant.
And, I apologize, it looks like that the advise I gave you (for disabling the periodic GetStatus check) was wrong. It only applies to OPC COM. The XML-DA has a different implementation which ignores this parameter. I will need to discuss with the developer what we can do to disable the GetStatus call in XML-DA. There isn't currently a setting for that. And we are not quite sure that, after doing it, things will start working.
Regarding the port choice in URL: This has been tested and should work, I do not think it is the cause.
I will post another reply here after we decide what the next step should be.
Best regards
Please Log in or Create an account to join the conversation.
Have you tested a case when url is configured to use another port, in my case 6010?
BTW, if you have library with internal debug logging i can try it.
Please Log in or Create an account to join the conversation.
Sorry for the delay in replying. Disabling the periodic "OPC status" check does not help.
I run wireshark to analyze packets
1. When I choose "TCP Connection test" I catch response (see attached file )
2. When I select "Refresh" - nothing. I don't see anything
I cant understand what is wrong
Please Log in or Create an account to join the conversation.
1. In Connectivity Explorer, perform Tools -> Configure Connectivity.
2. Select "OPC DA Configuration ...". under Members. Select Selector -> Shared Parameters -> Client Parameters -> Server Status Check period in the right pane.
3. Enter -1 in the property grid next to "Server Status Check".
4. Press OK to close the the "Configuration Part Collection Editor" dialog.
5. Restart Connectivity Explorer (you might be asked to do so).
6. Retest.
From the code: Set EasyDAClient.SharedParameters.ClientParameters.ServerStatusCheckPeriod to Timeout.Infinite (-1), it should disable the periodic calls to GetStatus.
Note that this is a static property on EasyDAClient class, it influences connections to all servers, and it needs to be set once, before any actual instances of EasyDAClient are created.
Best regards
Please Log in or Create an account to join the conversation.
- Forum
- Discussions
- QuickOPC-Classic in .NET
- Connections, Reconnections, COM/DCOM
- OPC XML-DA. Communication problem