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Subscriptions

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03 Jul 2022 17:25 #11028 by support
Replied by support on topic Subscriptions
Hello.

The error "The item ID is not defined in the server address space or no longer exists in the server address space." always comes from the OPC server, we never generate it ourselves on the client side. If your Item IDs are correct, it almost always indicates either a bug or misconfiguration in the OPC server. In theory one can imagine a bug in QuickOPC that would "damage" the item ID and thus cause the error, but this kind of bug is very unlikely.

I currently do not know what can be causing the "Cannot connect..." error - as it says, it is in principle a timeout.

As an experiment, can you please turn off the optimizations described in the following article?:
opclabs.doc-that.com/files/onlinedocs/QuickOpc/Latest/User%2...html#OPC%20DA%20Optimizer.html

With QuickOPC, all errors in subscriptions should cause retries, eventually - i.e. the expected behavior is that things that gave an error will start working at some later time - provided that the server works OK.

Regards

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01 Jul 2022 12:16 #11024 by spicerno
Replied by spicerno on topic Subscriptions
We installed Matrikon Simulation Server (v1.5.0.0 as we were unable to install the latest one, we miss requirements and we are not owner of the machine).
We developed a stand-alone application (TEST APPLICATION) with the same code of the main service (MAIN APPLICATION).
We import into Matrikon Simulation Server a lot of random Int items.
we have configured TEST APPLICATION similar to MAIN APPLICATION:
800 items in Subscription with rate 20000 and batch 10 (SubscribeMultipleItems[10])
400 items in Subscription with rate 170000 and batch 10 (SubscribeMultipleItems[10])
100 items in Read (custom polling thread) with rate 3600000 and batch 10 (ReadMultipleItems[10])

TEST APPLICATION on Matrikon Simulation Server seems to work as it should be.

On Remote Production Server some subscriptions are received after a long time, and sometimes we get the error "The item ID is not defined in the server address space or no longer exists in the server address space." but this is not true, does this error stop the subscription?
we noticed that read operations return the error "Cannot connect topic (timeout)." the first few times.

From tests it seems a server-side issue, but the client with the old version of quickOPC did not have these problems.

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29 Jun 2022 20:27 #11019 by support
Replied by support on topic Subscriptions
Hello,

are the issues reproducible with our simulation server, or any OPC server we can get our hands on?

Thank you

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28 Jun 2022 13:04 #11016 by spicerno
Replied by spicerno on topic Subscriptions
Hi,

I have a test application which contains only the code that uses QuickOPC library. I use this to simulate the main application.
The cases described in the previous message switch randomly.

Regards.

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28 Jun 2022 10:31 #11015 by support
Replied by support on topic Subscriptions
Hello,

the two versions you tested are quite far away from each other, and there were multiple changes in between; while it is good to know that it worked in 5.54.x, we need to focus on the current version (5.63.246).

Do you perhaps have a reproducible scenario (small test app) for at least one of the issues?

Best regards

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28 Jun 2022 09:47 #11014 by spicerno
Subscriptions was created by spicerno
Good morning,

We have an application that uses simultaneously subscriptions and read, with QuickOPC version 5.54.1151.1.
After updating to version 5.63.246 we found a new weird behaviour on subscriptions:
- sometimes only a part of subscriptions is notified and we have to wait a long period in order to have the remaining too;
- other times all subscriptions are notified but after a short time we do not receive anything and no error is returned.

Using the application with the old version (5.54.1151.1) none of these occurred.
In another topic I opened you found an interlocking problem between item subscriptions and reading, can it be related?

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