The Generic OPC UA Server Framework
Design File Manual
Class
Cachevariable
Attributes of cachevariable
addressSpaceWrite
makeSetGet
This attribute is deprecated and will be completely removed soon.
dataType
initializeWith
Determines what the cachevariable will be initialized with before any custom code or any OPC UA client write is effective.
- When configuration, an appropriate entry is made in the Configuration.xsd file which in turn adds s
initialValue
initialStatus
When initializeWith=valueAndStatus, this attribute gives the initial status of the cachevariable.
When initializeWith is different, this attribute is ignored.
isKey
nullPolicy
- When nullForbidden, the cachevariable is never allowed to contain NULL. This applies to setters (Device Logic can't set NULL), OPC UA Client write operations (write operation carrying NULL will be denied) and initialization (when initializeFrom=valueAndStatus, initialValue is mandatory to be given). Also, thanks to this setting a short getter will be created.
- When nullAllowed, there is no restriction towards NULL.
Relations between nullPolicy, initializeWith and initialValue attributes
nullPolicy
| initializeWith
| initialValue
| Comment
|
nullAllowed
| configuration
| NOT RELEVANT
|
|
nullAllowed
| valueAndStatus
| - If not present, the value is initialized as NULL.
- If present, the value is initialized with the attribute contents.
|
|
nullForbidden
| configuration
| NOT RELEVANT
|
|
nullForbidden | valueAndStatus
| MUST BE PRESENT
|
|