Echelon LNS DDE Server - Manual (Page 134)

handle for the Subsystem containing the targeted function block or device,
and is the topic type supported by the LNS DDE server.
11. Select LNS5LMNV and click the Modify button to review the definition of the
Access Name using the following dialog:
In this dialog you define the Application and Topic portions of the DDE link.
The LNS DDE Server only supports DDE as a protocol. The default,
‘Advise only active items’ option is selected. This option allows you
to limit the polling of the application to the points currently monitored by
active windows on screen and to points being logged or alarmed by InTouch.
InTouch is very efficient in the way it manages DDE links. Once a point is
created, InTouch does not destroy the link when the point is no longer in
view. Instead, it deactivates the point causing polling to stop while leaving
the data structures in place so the next access to the point will occur quickly.
Other HMI applications may actually destroy the link when a point is no
longer in focus (this is a key benefit of InTouch).
Close the dialogs just opened using the Cancel buttons to avoid any changes.
Network Variable Monitoring
The Monitoring NVs window is the main window of the example application. It
shows simple animation examples for monitoring the three most common
network variable types used by the LonPoint system (and many other
LONWORKS applications). The top frame shows digital data presented using
three different techniques. The last section described how the formatted
message view of a variable using the SNVT_switch type is defined. The
animated LED is a more visually appealing mechanism to present this data (see
figure 9). In this case, a tag that looks at the state portion of the variable is
defined.
To see how an LED is configured in InTouch, follow these steps:
C-8 WonderWare InTouch Example