Echelon LNS - Manual (Page 179)

LNS Programmer's Guide 165
3. Call PreMove() on the AppDevice. When you call PreMove(), you must
specify the destination channel as the newChannelObject element. You
can optionally specify the destination subnet as the newSubnetObject
element. Echelon recommends that you leave the newSubnetObject
element empty, as LNS will then allocate the most suitable subnet for the
destination location:
NSDAppDevice.PreMove(channelObject, NOTHING)
NOTE: You can use the PreMove() method to move a device from one
subnet to another, without switching channels. In this case, specify the
device’s current channel as the newChannelObject element, and the
new subnet as the newSubnetObject element.
4. Physically move the Network Service Device.
5. End the current session, and start a new one. Then, call
PostMove()
on
the AppDevice to complete the operation.
MySystem.EndSession()
MySystem.BeginSession()
NSDAppDevice.PostMove()
MySystem.EndSession()
MySystem.CommitTransaction()
LNS applications that are designed for mobile use, such as a diagnostics tool for a service
technician, may find it difficult to follow the procedure described above. Typically, the
application will be used in location A, terminated, and started up in a different location B
later (the next service case). Since location B may not be known at the time when
location A is left, the tool may not be able to call PreMove() before physically moving the
device.
If the LNS application is a Local or Lightweight client application whose Network
Service Device has been moved, the calls to the PreMove() and PostMove() methods
can be performed after the network interface has been physically moved. If you are
performing this procedure with a remote Full client application, it is not necessary to call
the PreMove() or PostMove() methods in this case, as the move is performed
automatically when the system is opened. However, you must open the network via the
Networks collection (and not the RemoteNetworks collection). See the next section for
more details on this.
Remote Full Clients
There are several other factors to consider if a remote Full client application has been
using the Network Service Device you are moving. When a remote Full client application
opens a database using the Networks collection (as opposed to the RemoteNetworks
collection) and no other application currently using that Network Service Device has the
database open, the Network Service Device connects with the LNS Object Server. As part
of this connection process, the LNS Object Server determines which channel the Network
Service Device is using. If the Network Service Device had been created previously on a
different channel, which would be the case if it has been moved, the LNS Object Server
will move it to a new channel and assign it a new address, updating connections and
timers appropriately. Thus, the LNS Object Server handles the move automatically for
you in this case.