Echelon LNS - Manual (Page 199)

LNS Programmer's Guide 185
MoveToInterface() method to move a dynamic network variable from the main
interface to a custom interface. Once you have done so, you could remove the network
variable from the custom interface, and its removal would be propagated to the main
interface.
Tracking Custom Interface Changes
You can use the
OnNodeIntfChangeEvent
event to keep track of when a device’s
interface is modified. The
OnNodeIntfChangeEvent
event is fired whenever a device's
interface is changed. Depending on the type of interface change, the
OnNodeIntfChangeEvent will be generated as the changes are made to the LNS
database, or as they are propagated to the physical device. You can register your
application for this event by calling the
BeginNodeIntfChangeEvent()
method on the
System
object.
For more information on this, see the LNS Object Server Reference help file.
Changeable Network Variable Types
As of LNS Turbo Edition, each NetworkVariable object contains a TypeSpec property.
The TypeSpec property provides access to a TypeSpec object. LNS uses the TypeSpec
object to identify the base type a network variable should use. You can write new values
to the properties of the TypeSpec object to change the network variable’s type, if the
network variable supports changeable types.
To change a network variable’s type, follow these steps:
1. Check that the network variable supports changeable types. You can read
the NetworkVariable object’s ChangeableTypeSupport property to do
so. If the ChangeableTypeSupport property is set to
lcaNvChangeableTypeSdOnly or lcaNvChangeableTypeSCPT, the
network variable supports changeable types.
2. Access the network variable’s TypeSpec object through the TypeSpec
property.
3. Set the program ID, scope, and name of the new type you want to use by
writing to the ProgramId, Scope, and TypeName properties of the
TypeSpec object.
4. Optionally, invoke the Lookup
()
method on the TypeSpec object to
make sure that the program ID, scope and name entered in step 3
reference a valid type.
5. Read the IsComplete property to make sure that the TypeSpec object is
complete. This step is generally not necessary when changing a network
variable’s type, unless you are creating a new network variable or
changing a network variable’s type from a type that was received from
another network variable. Consult the LNS Object Server Reference help
file for more information on the IsComplete property.
6. Pass the modified TypeSpec object back to the TypeSpec property of the
network variable. At this point, LNS will use the values entered in step 2
to find the definition of the type in the resource files, and assign values to