Echelon OpenLNS - Manual (Page 866)

OpenLNS Programmer's Reference 829
Subsystem
The Subsystem object represents a logical grouping of devices and routers. Subsystems may
be hierarchical. Each user-defined subsystem may itself contain additional user-defined
subsystems.
The
System object's Subsystems collection contains the top-level subsystems in the user's
subsystem hierarchy plus two pre-defined subsystems: the ALL and the Discovered
subsystem. These predefined Subsystem objects are described as follows:
• The ALL subsystem is always given index 1 within the System object’s Subsystems
collection. This subsystem contains all objects in the network database, including the
subsystems in the system that are managed by the LNS client applications. However,
this also includes transient objects that OpenLNS uses that should not be accessed by
client applications. In general, you should not use the ALL subsystem, and you should
not iterate through this subsystem to get a list of devices or routers on a network.
The ALL subsystem, however, may be useful if you are not sure to which subsystem a
device or router belongs, but you know the handle or Neuron ID of the device or router.
In that case, you can locate the device by accessing AppDevices or Routers collection of
the ALL subsystem, and invoking the ItemByHandle or ItemByNeuronId methods.
A newly discovered uninstalled router (by service pin, or device discovery) will not
appear in the ALL subsystem's RouterDevices collection until the
Discovered.Uninstalled.RouterDevices collection is accessed.
• The Discovered subsystem is always given index 2 in the System object's Subsystems
collection. The AppDevices and RouterDevices properties in the Discovered subsystem
are empty collections; however, this pre-defined subsystem contains two special-purpose
subsystems: the Installed and Uninstalled subsystems. These two special-purpose
subsystems are described as follows:
o
The Discovered.Installed subsystem is always at Index 1 in the Discovered
subsystem. It contains all devices that were not explicitly added to a subsystem by an
OpenLNS client. For example, all NSDs will initially be in this subsystem because
they are created implicitly by OpenLNS. If you use the Move or MoveEx method to
move an NSD or application device in the Disovered.Installed subsystem to a user
subsystem manually, or if you use the AddReference method to add a reference to a
device in the Discovered.Uninstalled subsystem to a user subsystem, the device
will be removed from the Discovered.Installed subsystem. Devices discovered by
network recovery operations are also stored in this subsystem, until they are moved
by an application to a user subsystem.
o
The Discovered.Uninstalled subsystem is always at Index 2 in the Discovered
subsystem. It contains unconfigured devices that have been automatically
discovered on the network or devices that have been discovered by the System
object's DiscoverDevices method.
Write access to the application devices and routers contained within these
subsystems is limited. Devices may not be added to or deleted from these
subsystems; however, they may be moved to other subsystems, effectively installing
them using the AddReference method of the AppDevices or Routers collections. You
can rename the application devices and routers stored in these subsystems by
writing to their Name property, but you cannot commission them or modify their
Neuron IDs until you move them to another subsystem.