The OPC UA BaseObjectType is modelled in AML as a SystemUnitClass with the same name. The BaseObjectType SUC contains attributes that mimic the attributes of the OPC UA Object and ObjectType NodeClasses, as shown in Figure A.10.
Figure A.10 – BaseObjectType Attributes
In OPC UA, the set of attributes appears on the type as well as the instances and the values on the types are often used to convey a default value on the instance. In AML, only one set of attributes is used since both a Value and DefaultValue can be specified for every attribute in AML.
Table A.6 shows the additional attributes introduced by the BaseObjectType SUC.
Table A.6 – Mapping UA Object/ObjectType NodeClass attributes to BaseObjectType SUC attributes
|
Attribute name |
Included in SUC or Instances |
Notes |
|
IsAbstract |
X |
If not present in the AML SUC type, the value is assumed to be FALSE. In instances, this attribute has no meaning and should be deleted or ignored. |
|
EventNotifier |
X |
If not present in the AML Object, the value of all fields is unknown. OPC UA Servers may override some or all of the configured values |