Professional OPC
Development Tools

logos

QUICKOPC.COM and VB6

More
19 Sep 2012 11:59 #1026 by support
Replied by support on topic QUICKOPC.COM and VB6
Hello. The build that has a fix for the problem we have found is now on the public Web, in the download area (it announces itself as 5.12.1392.1).
Thank you for cooperation, hopefully this will resolve your problem.
Best regards

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

More
18 Sep 2012 11:38 #1024 by support
Replied by support on topic QUICKOPC.COM and VB6
We have found a memory leak with InvokeXXXX methods. In our analysis, it would only appear if there was an error performing this operation (no leak if it went successfully). There may also be a related thread leak (not confirmed yet).
We are working on further analysis and a fix for this. Please wait for next post.
Regards,

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

More
16 Sep 2012 17:45 #1018 by support
Replied by support on topic QUICKOPC.COM and VB6
This kind of check is up to your application. It should not be part of the component, because in general case, writing to OPC items that exhibit Bad quality upon reading is not an invalid operation, and depending on the OPC server, it may even have a specific meaning and intentionally be used. In addition, the Read and Write cannot be performed together as one atomic operation through OPC interfaces, and if there is a problem at one moment, it may be gone a moment later.

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

More
14 Sep 2012 15:07 #1016 by lrs
Replied by lrs on topic QUICKOPC.COM and VB6
Normally there should be no writing outside time program changes, but I found that when there is a com error (i.e bad quality from PLC) the program will attempt to write to variables (by InvokeWriteItemValue) in the PLC over and over again (every minute). Because there was no check for OPC Quality before writing. I have now changed this so that the program does not attempt to write when OPC Quality = 0 (Bad), 4 (Config error), 8 (Not connected) and 14 (Com failure). We will install this update on some of our servers within next week or so, and continue testing but if this is the problem maybe this check should maybe have automatically performed within OPCLabs?
Regards, LRS

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

More
10 Sep 2012 15:10 #1015 by support
Replied by support on topic QUICKOPC.COM and VB6
We do not directly log this error, but it looks quite relevant to this problem. It could be that either our process, or something else in the system, is consuming the threads. I will try to see if this can be related to InvokeXXXX method.
On your side, with this particular error, it is very important to determine which process is responsible for this. You should set up either task manager or process monitor and observe/log the number of threads consumed by each process.

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

More
10 Sep 2012 14:58 #1014 by support
Replied by support on topic QUICKOPC.COM and VB6
From: .....
Sent: Monday, September 10, 2012 11:21 AM
To: Zbynek Zahradnik
Subject: OPCLabs forum - new post, update

By the way,

Our log file has catched the error:
“No more threads can be created in the system” several times, seems like it has been logged after “InvokeWriteItemValue” to the system with no communication.
Does this error come from OPCLabs?

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

More
10 Sep 2012 14:54 #1013 by support
Replied by support on topic QUICKOPC.COM and VB6
Thank you. The fact that you are using InvokeWriteItemValue is new to me. Calling this methods has not been included in the test made earlier.
Can you quantify how many calls to this method, and with how many items, can accumulate over time? We can make a test with this method as well.
The queue sizes should rather be set higher, not lower. If a queue is filled to the limit at any moment, it means a serious problem because the system is not coping with the load, and notifications get lost.

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

More
10 Sep 2012 09:00 #1011 by lrs
Replied by lrs on topic QUICKOPC.COM and VB6
Hello again,
I forgot the questions from May, the answer is as following:
- For writing the method InvokeWriteItemValue is used. This is called from timers (time program etc), but normally no writing is performed when no time program changes and no users logged in
- for reading, only subscription is used, no one-time reading
- abandon interval minimum had always been unchecked
Have you found out more about this recent months? The problem is still there. Today the memory consumption of OPCLabs on one of our servers reached 2GB. The reason was com failure in one of the buildings in the system (covering about 2000 out total 40000 opc items in server, this system had no com during weekend).
Have you any suggestions about other settings we can try? What about the queue sizes, should we try to reduce them ? When we started using OPCLabs the system crashed very often, then we increased the queue sizes, and there were no more crashes, but has this something to do with the memory consumption ?
Best regards, LRS

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

More
18 May 2012 11:29 #861 by support
Replied by support on topic QUICKOPC.COM and VB6
Hello,
we have set up a long-running test with following parameters:

QuickOPC-COM 5.12.1305.1
queue sizes increased according to your picture
client test application subscribing to 12,000 items
each item changing on the server once in 10 minutes (in a phased manner), giving an average rate of change of 20 changes/second
server failure (with OPC_STATUS_FAILED) simulated every 10 minutes (that's quite often...)

We ran this test for approx 2.5 days, and collected the memory consumption (Private Bytes counter) using Windows performance monitor. Unfortunately, no relevant increasing trend in memory consumption could be observed: The "baseline" stayed around 72-73 MB.
We will continue trying to reproduce the problem with different and more "harder" settings. Can you please answer the following as well:

Is your application also using "one-time" reads and writes, or is it just permanently subscribed as our test application is? Can you describe the general "usage pattern" of QuickOPC methods in your application?
I am still not sure about the setting for "Abandon interval minimum:. Are you running with it checked, or unchecked?

Thank you

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

More
07 May 2012 08:39 #844 by lrs
Replied by lrs on topic QUICKOPC.COM and VB6
Hello,
"Huk vekk denne" means "Uncheck this" in Norwegain (not meant for you!), as an internal message to our engineers because we have been using the same settings on all servers with OPCLabs.
Error -1073442815 occurs from time to time also on other of our SCADA servers, from different OPC server connections, where we use Matrikon Tunneller and OPCLabs. If you dont' have any better suggestion, we think it indicates that there has been a network fault so that connection between communication server and SCADA server has been lost. (Also get the same message if comm. server is being restarted)
Thanks for looking at our problem, we will inform the customer, and hopefully we will have this problem solved. Please tell if you want us to try different program settings on the server.
Best regards,
LRS

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

Moderators: support
Time to create page: 0.249 seconds

      

 Recommend this on Google