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