Reconnection of client and monitored item refresh afterwards|OPC UA Standard|Forum|OPC Foundation

Hi,

I have some troubles with my Ua Client reconnecting to a OPC server (Siemens PLC 1518) and obtaining monitored item changes during the connection loss.

Environment:
– .net 5, C#
– Ua.Cient and Ua.Core and Ua.Configuration 1.4.367.75
– Server Siemens 1518 PLC

I have a lot of subscribed monitored items. What I would like to achieve is that in case of a network failure a reconnect should start, after the reconnect is successful the client should update all monitored items (if the value changed in the meantime).

I implemented already a reconnect via SessionReconnectHandler which basically works and reconnects to the server. After the reconnect I call “ConditionRefresh()” for every used subscription as I thought this will update changes which happened during the connection loss. However, this works not every time as I saw two cases:

1) Short network interruption (< ~15s), reconnect establishes session with same session ID as before. ConditionRefreh() indeed updates monitored item changes which happened during connection loss.
2) Longer network interruption(> ~15s), reconnect establishes session with new session ID (old session got closed). ConditionRefreh() does not update any changes which happened during connection loss.

Is there a way to achieve what I want?

Thanks!

Markus