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Threading/Periodic Worker Processes

07 Mar 2024 12:10 #12623 by support
Received, but double posted - will be handled here: .

Best regards

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06 Mar 2024 14:44 #12620 by KPersyn33
A customer has reached out to our team because they were able to identify an issue with their project that contains OPC Data Client. Unfortunately, this is not something that they are able to record or provide a replicable project for, so I have provided all of the information that they have provided to us below.

Ultimately, we are looking to get information on the possible threading/periodic worker processes that could be having an effect on this.

A PCIe-C1553 card from Avionics Interface Technologies (AIT) is installed. This PCIe card is connected to the customer’s Time Server to read IRIG time and to receive Sync Pulses at 100Hz. The PCIe card receives a pulse every 10 ms and communicates to the application via an interrupt-driven event handler. The event handler reads the IRIG time and updates a pulse counter to be used for application synchronization. If the events are not handled in a timely manner the event status queue will overflow. The event status queue has a depth of 256.

Version is OPC Data Client v2022.1, though the user is in the process of testing with the latest release. The user has been successfully running their application on 5 different PCs, using Windows 10 Enterprise version 1607 (OS Build 14393.1198 and 14393.447) and Enterprise version 1703 (OS build 15063.726 and 15063.502).

When they tried to run the application on a new PC running Windows 10 Enterprise version 22H2 (OS Build 19045.3996), that is where they ran into problems. After a variable amount of time the event status queue for the incoming Sync Pulses overflows. After approximately 2.5 seconds, the event handler resumes receiving Sync Pulse events. They were able to determine this because the Sync Pulse counter and the IRIG time is sent to a queue in the Event handler to be logged to a file in another task. They also log when the status queue overflows.

To determine the root cause of the Sync Pulse interrupt problem, the user have tried to isolate the various components of the application code. Having only the AIT IRIG and Sync pulse portion of the code running along with some basic logging does not present any problems.

When they removed the call to client = new EasyUAClient(), the problems stopped occurring. They were able to confirm that when using ClientAce in place of OPC Data Client, the application does not exhibit any problems either.

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