Echelon Neuron C - Manual (Page 57)

Neuron C Programmer’s Guide 45
• Changeable-Type Network Variables on page 68 describes how to
implement network variables that allow their type to be changed at
installation time.
Overview
As described in Chapter 1, Overview , a network variable is an object that
represents a data value and may be connected to multiple devices on a network.
How many network variables a Neuron-hosted device can support depends on the
device’s memory map, the system firmware, and the development tool version, as
shown in Table 6.
Table 6. Network Variable Limits
Neuron System
Firmware Version
NodeBuilder
Development Tool
Version Maximum Number of
Network Variables
Version 15 or earlier Any 62
3.1 or earlier 62
Version 16 or later
FX or later 254
The maximum number of network variables for applications developed with the
Mini EVK Evaluation Kit or the Mini FX Evaluation Kit is 32. The limits for
host-based applications depend on the development product used.
Important: The NodeBuilder CodeWizard declares network variables so that
they are placed in RAMNEAR memory by default. However, because of the
larger number of network variables that are available for devices built with the
NodeBuilder FX Development Tool, your device could run out of available
RAMNEAR memory. In this case, declare as many network variables as
necessary to use RAMFAR memory:
1. Within the NodeBuilder CodeWizard, right-click the network variable
and select Properties to open the NV Properties dialog.
2. Within the NV Properties dialog, click Advanced to open the Advanced
NV Properties dialog.
3. Within the Advanced NV Properties dialog, select far. Click OK to close
the dialog.
4. Within the NV Properties dialog, click OK to close the dialog.
Network variables are defined within the program that runs on an individual
Neuron Chip or Smart Transceiver. As an example, consider a lamp program
with one network variable, named nviLamp (see Figure 6 on page 46). Also,
consider a switch program with one network variable, named nvoSwitch. The
same lamp program is installed on each of the three lamp devices, and the same
switch program is installed on each of the two switch devices in the figure.