Connection deactivation and invalid bit settings
Most of the WinCC OA standard drivers have the possibility for the user to activate and deactivate the connection to a device. This is usually done via an internal data point element like "active" or "enable" of the respective connection.
Since the deactivation of a connection is a requested user action, in this case the invalid bits on connection loss are not set on the related input or input/output addresses. This means the invalid bits are only set if an active connection is either lost or cannot be established.