Echelon LNS - Manual (Page 237)

LNS Programmer's Guide 223
connected to an input on another device. However, this is usually not the appropriate
setting for a fan-out connection, as this will generally result in sending out individual
messages for each input network variable.
You could then write to the value of the output network variable to update the values of
all of the input network variables on the fan and vent devices at once. Figure 9.2 shows
an example fan-out connection where an output network variable is connected to input
network variables on two devices on the network.
Fan Device
Two
Fan Device
One
nviInput1
nviInput2
Target Network Variables
LNS Application
PC
nvoValue
Figure 9.2 Fan-Out Connection
Creating and Using Host Network Variables
Host network variables are network variables that are created on the PC running the
monitor and control application (or on the PC running the LNS Server, for a Lightweight
client application). These network variables can be used just like network variables on
application devices, although they are frequently used to support bound monitoring and
control by the LNS application. To use host network variables in this scenario:
1. Create a custom interface and define the network variables to be used on
the host PC. You can create these dynamically after the system has been
opened. See Defining Host Network Variables on page 224 for more
information on this.
2. Connect the network variables on the device you want to monitor to the
network variable on the host PC, as desired. For information on creating
connections, see Connecting Devices on page 138.
3. Create a monitor set to monitor the network variables on the devices you
want to monitor. Then, implement code for an
OnNvMonitorPointUpdateEvent
event handler, or set up a polling
scheme that will explicitly read and write the value of the host network
variable.