Echelon IzoT NodeBuilder - Manual (Page 157)

4. Optionally, you can click Advanced to open the Advanced NV Properties dialog and further
specify the storage class used by the network variable. Consider a scenario where you declare a
large network variable array that exceeds the limits of the near RAM segment, which is 256 bytes.
In this case, you need to move the network variable array to the far RAM segment by selecting the
far check box in this dialog. For more information on managing memory resources, see Chapter 8
of the Neuron C Programmer’s Guide.
You can set the following properties and then click OK to return to the NV Properties dialog:
NV Class You can specify the following storage classes for the network
variable.
const The network variable is of const type. The Neuron C compiler will
not allow modifications of const type variables by the device’s
program. However, a const network input variable will still be placed
in modifiable memory and the value may change as a result of a
network variable update from another device. Selecting this class
disables the uninit keyword option.
When used with the declaration of a configuration network variable
(CPNV), the const storage class prevents both the Neuron C
application and network tools from writing to the CPNV. The
application may cast away the affects of the const type property to
implement device-specific configuration properties as configuration
network variables. However, the network variable will be placed in
modifiable memory; therefore, network variable connections may still
cause changes to such a configuration network variable.
eeprom The network variable is placed in EEPROM or flash memory instead
of RAM. All variables are placed in RAM by default. EEPROM and
flash memory is only appropriate for variables which change
infrequently because of the overhead and execution delays inherent in
writing such memory, and the limited number of writes for such
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