diff --git a/src/Core/ZB.MOM.WW.OtOpcUa.Core.Abstractions/IHistoryProvider.cs b/src/Core/ZB.MOM.WW.OtOpcUa.Core.Abstractions/IHistoryProvider.cs index 70e089bd..6a337153 100644 --- a/src/Core/ZB.MOM.WW.OtOpcUa.Core.Abstractions/IHistoryProvider.cs +++ b/src/Core/ZB.MOM.WW.OtOpcUa.Core.Abstractions/IHistoryProvider.cs @@ -95,9 +95,10 @@ public interface IHistoryProvider /// /// Request cancellation. /// - /// Default implementation throws. Only drivers with an event historian (Galaxy via the - /// Wonderware Alarm & Events log) override. Modbus / the OPC UA Client driver stay - /// with the default and let callers see BadHistoryOperationUnsupported. + /// Default implementation throws. Drivers whose backend can serve historical events + /// override: Galaxy (Wonderware Alarm & Events log) and the OPC UA Client driver + /// (forwarding HistoryReadEvents to its upstream server). Raw-only drivers such as Modbus + /// stay with the default and let callers see BadHistoryOperationUnsupported. /// /// Note the type asymmetry with / /// (both use uint maxValuesPerNode): event