With an online Lon device, you can access/use LonData values directly without making proxy points. For example, from the device’s property sheet, you can expand any of the nci or cp LonComponents and review values, and if necessary make a value change. When you execute a , the change is written down to the device (Figure 49).
You can also change nvi LonData values in the same way, however, nvi values are typically overwritten again. Note that you cannot directly change nvo LonData values (these are read-only), but for any LonComponent you can issue a “Force Read” action—see LonComponent actions.
Without requiring Lon proxy points, you can also make Px view usage of LonData.
For “simple monitoring” from Px views, you can “data bind” Px widgets to LonComponent ords to retrieve LonData values, without requiring proxy point creation. However, note the following about this LonData usage:
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Polling is used to fetch LonData values, whereas if you create proxy points for items you can (and typically do) create Lon binds to the LocalDevice (using the Lon Link Manager) to receive values via “nv updates.” Overuse of polling may adversely affect Lon network traffic.
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Data logging or alarming (on value) requires a proxy point, where you add and configure history and/or alarm extensions, as needed.
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Using LonData values in station control schemes also requires proxy points.
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An nvi, nci, or cp represented with writable proxy points offer a Px view user “right-click” command access to set/override values. However, if Px view access to these items is via LonComponents (LonData), available actions are limited to “Force Read” (poll) or “Force Write” (resend value in station). See the next section, LonComponent actions.