OPC UA provides an mechanism to expose the local time of a Server, by the optional Property 0:LocalTime on the 0:Server Object (defined on the 0:ServerType in OPC 10000-5). This Property is also used as optional Event field.
Assets managed by a Server may be in a different time zone than the Server. Therefore, the same Property as on the Server Object should be used to expose the local time of the asset, i.e. a Property with BrowseName 0:LocalTime having the DataType 0:TimeZoneDataType or a subtype.
Servers may set the 0:LocalTime Property to be writable to allow Clients to set the local time of an asset. Servers may provide the 0:LocalTime with a Null Value in case the local time is unknown to the Server and not set by any Client.