Blocking UA Gateway

[saala]

Hi support team,

we are using the UA Gateways to get a OPC UA interface to a Intellution iFix 3.5 system. This works really fine, but we can reproducible bring the gateway into a blocking state. In this state the OPC UA clients (our opc ua sdk based appication or UA Expert) cannot communicate with the gateway any more. This problem occurs whenever we read OPC items that are not existing in the iFix OPC DA namespace for a longer period of time (e.g. 30 not existing tags for about 24h).
Then the UA Gateway comes into a blocking state:
- UA Gateway: Systray is still 'green', but it does not react on service stop/start any more. Partially the service is running because the log is still filled. (see log below)
- Configuration tool: connection is diconnected, no connect possible
- UA Expert: shows error messages (e.g. ConnectionWarningWatchdogTimeout)
- Our SDK based application gets 'Bad_Timeout' exceptions
It is still possible to access the iFix OPC DA server with other tools (we use 'PowerTool OPCDidw).
This happens only in combination with the iFix OPC DA server. We tried to get this state with a OPC DA simulation server, but this configuration works.
To solve the situation we kill the process in the Windows Task Manager and restart the service. (UA Expert reconnects automatically)

Extract from the UA Gateway log:
06:09:45.250Z|4|0D04* [uastack] OpcUa_Socket_HandleEvent: Exception at connect attempt 0.
06:09:45.250Z|7|1470* --> UaSubscription::checkPublishTimer [SubID=3]
06:09:45.250Z|4|0D04* [uastack] OpcUa_Socket_HandleEvent: Connect to all IP's failed. Giving up.
06:09:45.250Z|7|1470* UaSubscription::checkPublishTimer [SubID=4]
06:09:45.250Z|4|0D04* [uastack] OpcUa_SecureConnection_CancelOpenRequests: Canceling 0 open requests.
06:09:45.250Z|7|1470* <-- UaSubscription::checkPublishTimer time=100
06:09:45.250Z|4|0D04* [uastack] OpcUa_Channel_OnNotify: Underlying connection raised unexpected error event!
06:09:45.250Z|4|0D04* [uastack] * OpcUa_TcpConnection_SocketCallback: Event Handler returned.
06:09:45.250Z|4|1384* DONE OpcUa_Channel_Connect [ret=0x80050000]
06:09:45.250Z|4|1384* CALL OpcUa_Channel_Delete
06:09:45.250Z|4|1384* [uastack] OpcUa_Channel_Clear: waiting for channel access
06:09:45.250Z|4|1384* [uastack] OpcUa_Channel_Clear: deleting transport connection
06:09:45.250Z|4|1384* [uastack] OpcUa_TcpConnection_Delete: Stopping communication.
06:09:45.250Z|4|0D04* [uastack] OpcUa_P_SocketManager_ServerLoopThread: Stop Serving due stop flag.
06:09:45.250Z|4|1384* [uastack] OpcUa_TcpConnection_Delete: Communication stopped.
06:09:45.250Z|4|1384* [uastack] OpcUa_Channel_Clear: transport connection deleted
06:09:45.250Z|4|1384* [uastack] OpcUa_Channel_Clear: deleting secure connection
06:09:45.250Z|4|1384* [uastack] OpcUa_SecureConnection_CancelOpenRequests: Canceling 0 open requests.
06:09:45.250Z|4|1384* [uastack] OpcUa_Channel_Clear: secure connection deleted
06:09:45.250Z|4|1384* [uastack] OpcUa_Channel_Clear: done
06:09:45.250Z|4|1384* DONE OpcUa_Channel_Delete
06:09:45.250Z|1|1384* Error: Discovery Server not available

Thanks for your support
Michael

[Support Team]

Hi Michael,

Which version of the UaGateway are you using?
What Read function are you using (Sync, Async, registered)?
Which version of the iFix are you using?
Is there something else running in parallel on the UaGateway that also accesses the underlying iFix (write, being subscribed to other Items in the same namespace, configuration change, reconnect)?

In our testing we could not find any issues when trying to read "unknown" Items from an underlying server, besides getting error on the operation it all works fine and stable.

There seems to be some race condition that only occurs with the iFix, but with no other DA server.

Please send full trace of UaGateway (max trace level) to support@unifiedautomation.com.

[saala]

Hi,
our environment is

-Window 2003 Server (SP2)
-iFix 3.5
-UA Gateway 1.2.3

There is no other client application that accesses the iFix OPC DA server during our tests.
The client uses synchron data access (it invoks the UaClient.readValues(NodeId[], TimestampsToRetur) method, this method throws the Bad_Timeout exception)
I send the log-Files of the gateway to support@unifiedautomation.com

Best regards
Michael

[Support Team]

Users looking for help/solution on this topic should also read this:
http://forum.unified-automation.com/topic260.html

Best Regards
Support Team