Echelon LNS - Manual (Page 191)

LNS Programmer's Guide 177
Resolving Installation Failures
There are a few cases where attempts to register, add, or commission a device on a
network with multiple channels may fail or have negative side effects. This usually
happens when you attempt to install a device that was previously configured as part of
another network without deconfiguring it. You should also consider the following:
• If the device to be installed is configured on a subnet in the system’s domain that
violates the logical topology (i.e. a subnet on wrong side of configured or learning
router), LNS may need to force the device to the unconfigured state to
communicate with it. Thus, accessing a configured device may result in the
device becoming unconfigured.
• If learning routers are in use and the scenario described in case 1 is attempted,
the operation may result in the learning router not routing messages to the
conflicting subnet. The learning router must be reset to restore normal operation.
This is why it is important to use the PreMove() method during device
movement when learning routers are in the system as described later in this
chapter.
• If a device violates the logical topology (as in case 1) and is authenticated, it will
not be possible to install it. This is why it is important to use the PreMove()
method during authenticated device movement as described later in this chapter.
• If a device has the same address as the network interface on the LNS Server PC,
then the LNS Object Server will not be able to communicate with that device,
since the target device ignores all messages received from a device with its own
subnet/device ID. In this case, the device must be deconfigured. You cannot use
LNS to do so, since the LNS Object Server will not be able to communicate with
the device. So, you must choose another means to do so, e.g. by using a tool that
is configured on a different domain. During the development process, Echelon
recommends that you choose a different system domain ID to avoid this condition
following the creation of a new network database. Note that the LNS Object
Server uses a large node ID (e.g. 127) to help prevent this problem from
occurring.
Moving Devices and Routers Between Channels
At some point, you may need to move the devices on your network from one channel to
another. To do so, follow this procedure:
1. Call StartTransaction() to start a transaction, and then call
BeginSession()
to start a session.
MySystem.StartTransaction()
MySystem.BeginSession()
NOTE: If you are only moving a single device, you do not need to use a
session, but for optimal performance you should use a transaction to
perform these steps, unless the device uses authentication.
2. Obtain the device to be moved from the
AppDevices
collection. Or,
obtain the router to be moved from the
Routers
collection. The example
code in this section applies to an application device:
Set MyAppDevice = MyAppDevices.Item(“node12”)