When momentarily no variables are used in the runtime from a connection in the OPCUA client driver, the OPCUA client driver no longer sends service requests for the subscribtion that was previously created for these variables.
The OPCUA server will remove a subscription when it no longer receives any service requests for a subscription from a OPCUA client for a certain amount of time.
When variables are needed again in the runtime, e.g. when a screen is reopened, the OPCUA client driver attempts to reuse the previous subscription which was removed by the OPCUA server in the meantime, which results in a timeout.
The OPCUA client driver does not correctly validate the response from the server and does not create a new subscription. The variables remain INVALID in the runtime, until after a restart of the runtime.
When momentarily no variables are used in the runtime from a connection in the OPCUA client driver, the OPCUA client driver no longer sends service requests for the subscribtion that was previously created for these variables.
The OPCUA server will remove a subscription when it no longer receives any service requests for a subscription from a OPCUA client for a certain amount of time.
When variables are needed again in the runtime, e.g. when a screen is reopened, the OPCUA client driver attempts to reuse the previous subscription which was removed by the OPCUA server in the meantime, which results in a timeout.
The OPCUA client driver does not correctly validate the response from the server and does not create a new subscription. The variables remain INVALID in the runtime, until after a restart of the runtime.
An issue has been addressed in the OPCUA client driver. When a subscription has been deleted due to a timeout on the server when the server no longer received any service request for this subscription, the OPCUA client driver will react correspondingly on this timeout message and create a new subscription.
Also, the OPCUA client driver cyclically performs a read of the server status every half session timeout (by default the OPCUA client driver suggests a session timeout of 600 seconds, which may be modified by the server).