Echelon LNS DDE Server - Manual (Page 80)

variable that is driven by multiple output network variables (network variable fan-
in) is a typical example of how bound monitoring is not applicable. Polling is also
useful when you want to control the rate and volume of data being sent to your
monitoring application.
Monitoring Polled Output Network Variables
Device manufacturers can optionally specify network-related characteristics of the
device’s network variables. One characteristic that they can specify is that an output
network variable is a polled output. This means that the variable will only send
values when it is asked (i.e., when it is polled) — it will not generate event-driven
updates. To monitor the value of a polled output variable using the LNS DDE
Server, the LNS DDE Server must not be connected (i.e. bound) to the variable. If it
is not connected, the LNS DDE Server will automatically poll the variable to read its
value.
Output network variables on the LNS DDE Server host itself cannot be polled
outputs (but they may be updated).
Receiving Ongoing Updates Using Excel
Follow these steps to receive ongoing updates using Excel.
1 In the LNS DDE Server folder pane, navigate from the top level down
through the hierarchy to the network variable level.
2 Right-click the network variable that you want to monitor and select
Copy Link on the shortcut menu.
In Excel, right-click a cell on the spreadsheet and select Paste from the shortcut
menu. This will paste a formula with the following format on the shortcut menu:
=application|topic!item
If the topic or item contains spaces, it must be surrounded by single quotes (').
Now Excel will receive ongoing updates from the LNS DDE Server.
Example
=LNSDDE|'Network1.subsystem1.LMNV'!'AI-1.NO-1.SetTime- i20'
Note that the parameters are part of the item name and must be enclosed in single
quotes with the Item.
Receiving Ongoing Updates Using InTouch
Follow these steps to receive ongoing updates using InTouch.
5-10 Reading and Writing Network Variables