Echelon LNS - Manual (Page 135)

LNS Programmer's Guide 121
the device’s configuration as possible. These features are described in more detail
later in the chapter.
• If the device had been previously commissioned, and the device's old application
image and its new application image have the same program ID but a different
external interface, the LNS Object Server will leave the device in the
unconfigured state, and the NS:#59 lcaErrNsProgramIntfMismatch
exception will be thrown. Per LonMark guidelines, LNS requires that each
program ID be associated with only one external interface. This means that all
components and properties of each external interface using a given program ID
must be identical. However, LNS may not detect all violations of this rule, as it
would be very time consuming to validate this on every commission or after every
application download.
• An application loading session may be canceled by calling the system’s
CancelTransaction() method from within an OnSystemNssIdle event
handler, as described in Using the OnSystemNssIdleEvent on page 316. If the
load is canceled, the device will be left in the applicationless state. In this case,
the previous device application must be reloaded to restore the device.
Reloading a Device's Application
You should be aware that in some cases, reloading a device’s application may cause the
configuration properties on the device to be set to their original, default values. When
reloading a device’s application, Echelon recommends that you follow this procedure to
ensure that the configuration properties in the device are restored to match those in the
database in the most efficient manner:
1. Call DownloadConfigProperties() on the AppDevice. Use the
lcaConfigPropOptClearUpdatePending value as the
downloadOptions element.
MyDevice.DownloadConfigProperties(lcaConfigPropOptClearUpdatePending)
2. Call Load() or LoadEx() to reload the device application, as described
previously.
MyDevice.LoadEx(0)
3. Call DownloadConfigProperties() again. This time, specify the
lcaConfigPropOptLoadValues option as the downloadOptions
element. This will load the configuration properties stored in the LNS
database for the device back into the device.
MyDevice.DownloadConfigProperties(lcaConfigPropOptLoadValues)
Commissioning Devices
After you have assigned a device its Neuron ID (and loaded its application image if
necessary), you can enable it for communication with other devices on the network and
load its network image by invoking the Commission() or CommissionEx() methods.
This does the following:
• Gives the device a network (subnet/node) address in the system’s domain
if no DeviceTemplate or Channel were specified when the AppDevice