Professional OPC
Development Tools

logos

Getting 'Read not completed' and 'Write not completed' errors while trying to read from Softing.OPC.S7

More
20 Mar 2019 15:49 #7245 by support
I am glad to hear this.

Thanks for letting us know.

Best regards

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

More
20 Mar 2019 15:44 #7244 by Slavik
Hello,

I'm glad to inform that with latest build(5.54.1115) the issue is gone. Now everything works fine.

Thanks!

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

More
15 Mar 2019 17:33 #7216 by support
Hello.

Using the files the other customer has provided, we were able to reproduce the issue "Invalid *ppwQualities ...". It turned out to be a problem on our side. We have made a fix, and it is now available in QuickOPC version 2018.3 build 5.54.1115.0 or later. This build is now available on our Web site (under Downloads), and on NuGet. Please install it, and rebuild your project with the new assemblies.

We were not able to reproduce the first problem ("Read not completed. ..."). Due to the nature of the bug&fix we have made, however, it is possible that it had the same cause. So, I would be interested to know how it works on your side, in this respect.

Best regards

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

More
11 Mar 2019 13:14 #7196 by support
Both of these issues ("... not completed", or "Invalid *ppwQualities...") can either be problems on the server side (and QuickOPC just properly reporting them), or the server might be doing OK and QuickOPC might be giving false error reports - if there is a bug in QuickOPC.

We need a reproducible scenario to be able to troubleshoot this. It looks like another user has encountered the same issue recently, and thanksfully, he has provided some test project and server configuration files as well. We cannot, however, start work on it sooner than in the end of this week. As soon as I have any update, I will post a reply to your post here as well. It will most likely be the next week.

Best regards

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

More
11 Mar 2019 10:03 #7192 by Slavik
Hello,

I had the same issue with 'Read not completed.' error while reading data using 'ReadMultipleItems' method from the OPC server. Actually, setting AllowAsynchronousMethod property to false resolved the issue, but I've noticed that now I have another error popping up randomly from time to time when I'm using the same code to connect to another OPC server(Matrikon Simulator) : 'Invalid *ppwQualities returned from IOPCSyncIO2::ReadMaxAge(...). '.
Do you have any ideas why it might happens? I suppose that setting AllowAsynchronousMethod to false should not lead to random errors.

I'm using latest version of OpcLabs lib - 5.54.1026.1

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

More
28 Feb 2017 10:42 #4976 by support
Hello,

I do not know the reason yet. The errors indicate a timeout, that is, it looks like that the server has not indicated a completion of the operation to the client.

My wild guess is that (because we use asynchronous OPC reads/writes by default), the callback channel (by which the server indicates the completion) is somehow non-functional. For this reason, I would try to switch to synchronous OPC calls.

To do that, set client.InstanceParameters.Mode.AllowAsynchronousMethod to false.

BTW, have you tried some other OPC clients? (and choose between sync and async reads/writes, if they allow it)?

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

More
27 Feb 2017 17:15 #4975 by djorsher
Hi,

I'm trying to read and write to a Softing S7 server running on localhost, but getting errors.

I'm using OpcLabs.EasyOpc.DataAccess.EasyDAClient via the win32com client for Python.

I've installed on my machine (Windows 7) both the Softing S7 server and the Softing Demo Server.

When reading and writing from/to the Demo Server - it works.

The commands I'm issuing are:
client = win32com.client.Dispatch('OpcLabs.EasyOpc.DataAccess.EasyDAClient')
client.WriteItemValue('localhost','Softing.OPC.S7.DA.1', 'NodeB/Test1', 1)
client.ReadItemValue('localhost','Softing.OPC.S7.DA.1','NodeB/Test1')


I'm getting these errors:

1. Read not completed. This error indicates that it could not be verified that the requested read operation was completed during the timeout period. It is possible that the read operation will actually succeed or fail, but later. Increase the timeout period if you want to obtain positive or negative indication of the operation outcome. Other reason for this error may be that under heavy loads, topic request or response queue is overflowing. Check the event log for queue overflow errors (if event logging is supported by the product and enabled).

2. Write not completed. This error indicates that it could not be verified that the requested write operation was completed during the timeout period. It is possible that the write operation will actually succeed or fail, but later. Increase the timeout period if you want to obtain positive or negative indication of the operation outcome. Other reason for this error may be that under heavy loads, topic request or response queue is overflowing. Check the event log for queue overflow errors (if event logging is supported by the product and enabled).

After issuing the write operation, the item value is set to 1, but it hangs for a while, and then I'm getting this error.

Any help would be appreciated.

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

Moderators: support
Time to create page: 0.203 seconds

      

 Recommend this on Google