Professional OPC
Development Tools


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.

ErrorId OpcLabs.UAEngine=6411

08 Sep 2023 13:32 #12081 by support

Regarding the error 6411: The client side is reporting to you that the server is not shipping the data (or keep-alive messages) as quickly as it should. This is quite probably a problem on the server side, and it such case should be resolved there. In rare case, it could also be a problem on the client - for example, if the client process is overloaded and cannot cope with the frequency of the incoming messages.

The way to determine the root cause is to obtain the network communication captures (Wireshark) on the client computer, together with the client logs (form QuickOPC), and analyze them. If the network capture shows that the server is not shipping the as it should, you will need to resolve it with the server vendor (or it might be due to network infrastructure). If it shows that the server is shipping the data correctly but QuickOPC still report the error, we will need to look more closely onto the client side of things.

The instructions are here:

If you have servers on multiple machines and huge amounts of communication, the Wireshark capture should, if possible, be configured to filter the traffic with just one IP address.

Before doing so, however, have a look at the CPU usage on the client computer, and at the CPU usage taken by the client process. If it is suspiciously high, it can be the reason. In such case, you might have reached the hardware limits. Also, checking the CPU usage on the server side similarly.

Regarding your other post where you seem to indicate the the Write call took quite long: It is not the same thing as error 6411, but in quite the same way, it indicates that either the server is taking so long to fulfill the request, or that the client is overloaded. In this case it will be even easier to tell "who is at fault", with Wireshark capture - simply showing the communication around that single Write call, and comparing the Request and Response message timestamps.


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

08 Sep 2023 08:13 #12078 by xpycy001
There is a serious problem in the project production environment, opcUA report 6411 error code, detailed information is at the end.
6411 error, does it affect the write performance of tag values, How to Resolve 6411 Error。

Other information is as follows:
1 server Windows server2019
2 opcUA Version Info: OpcLabs. QuickOpc 5.71.334
3 The main program is:. NET 7.0 console exe
4 OpcUaClient has subscribed to approximately 80 OpcServers with approximately 5000 Tags,
5 Adjustment of subscription parameters, session duration, and other parameters, but error messages still exist
6 In most cases, the machine time where the opc server is located is not synchronized with the server where the current main program is located
7 The number of errors reported by 6411 on the same machine varies from day to day, sometimes more and sometimes less

The OPC-UA subscription ID 38 publishing has halted on the client session to endpoint URL "opc.tcp://" for approximate current duration of 106316 milliseconds. The current keep-alive count is 1000, the current publishing interval is 100 milliseconds, and the probationary period was 5000 milliseconds.
+ The client method called (or event/callback invoked) was 'DataChangeNotification'.

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

Moderators: support
Time to create page: 0.043 seconds