We are defining five classes of informational elements to be exposed on the interface. The classes are distinguished by their severity regarding the influence on the operation of the vision system.

Each message transports its severity represented as a value between 0 and 1000.

This class of lowest severity carries messages for debugging and diagnostic purposes. It may safely be ignored by clients.

This class may be used for messages that do not require that any client reads them for the normal operation. The vision system is able to safely continue normal operation even if this message is ignored.

A message of this class has a midlevel severity. The server can decide if for a specific message an acknowledgement, or acknowledgement and confirmation may be needed.

If on the vision system side a condition arises that could affect the normal operation of the system a message of this class should be created. An error message requires an acknowledgement from the client side. The server may decide that also a confirmation is needed.

This highest class of severity is used for error messages associated with problems that need human interaction. This kind of errors cannot automatically be solved, an operator has to do something in the physical world before the operation can go on. Acknowledgement and confirmation is mandatory for this class.

Table 128 – Information Elements

Information Type

Severity

needs Acknowledge

needs Confirmation

OPC UA Type

Persistent Error

801...1000

yes

yes

VisionPersistentErrorConditionType

Error

601...800

yes

optional

VisionErrorConditionType

Warning

401...600

optional

optional

VisionWarningConditionType

Information

201...400

no

no

VisionInformationEventType

Diagnostic Information

1…200

no

no

VisionDiagnosticInfoEventType