About adding Proxy Points to web charts

In Niagara 4.2 and later, when adding the Niagara proxy point to a web chart on a Supervisor, if the remote point on the controller has a history, the chart attempts to resolve the history on the Supervisor and use it to initialize the web chart.

NOTE: In order to detect the matching history for the proxy point, the history must already be imported or exported to the Supervisor.

Web Charts plot histories referenced by the historyConfig property and n:history tags. This is especially important with proxy points (history extensions on proxy points). When a proxy point is added to a web chart, it first checks to see if there is a local enabled history extension as a child on the proxy point (which is uncommon). If found, it uses the local history extension's historyConfig property to determine the history to plot in the chart. If a history extension is not found, it uses a computed n:history tag value if the history exists on the Supervisor (either through a history import or export). If the Persist Fetched Tags property is not enabled on the NiagaraNetwork, then only charting an individual proxy point will force a lookup of the supervisor's history to chart. However, this will not work for a point folder containing that proxy point.

When Supervisor station is subscribing to points on a subordinate station and if a point has a history extension and the history has been imported onto the Supervisor, then an n:history tag is added to the point.

NOTE: In order for the tag to be added to the point, you must first set the Persist Fetched Tags property on the NiagaraNetwork to true.

For a point folder (containing proxy points) which you drag and drop on a web chart, the n:history tag is used to plot the history. The web chart searches for n:history tags only on Numeric, Boolean, and Enum writable points. String points and string writable points are excluded even if they have the n:history tag because string points are not typically plotted in a chart.

NOTE: If an individual proxy point's history is not imported to the Supervisor then the web chart plots only live data for that point. Or, if an n:history tag is on a proxy point but the associated history has since been deleted from the Supervisor, then that point will not plot. Also, if you add a separate history extension to a proxy point with an existing history extension on the Supervisor then both of those extensions for that point will plot in the web chart.

In addition to adding individual proxy points to a web chart, you can also drag a point folder of proxy points onto a web chart and have it automatically find and chart the local histories (limited to the first 10 histories) for those points.

The following caveats apply in order for the proxy points in the points folder to plot on the chart:

First, the Persist Fetched Tags property on the NiagaraNetwork must be enabled.
The second caveat depends on the version of the JACE station connected to the supervisor via the NiagaraNetwork
- If the proxy points are for a N4.2 or later station in the Supervisor’s NiagaraNetwork, then the proxy points must be subscribed (or re-subscribed, i.e. the “Add” function) after all relevant histories have imported at least once. This ensures that the n:history tag information is fetched for all applicable proxy points.
- If the proxy points are for a N4.1 or earlier (including AX) station in the Supervisor's NiagaraNetwork, then the proxy points must be charted individually at least once after all relevant histories are imported at least once. This ensures that the n:history tag information is fetched for all applicable proxy points (it is not enough to re-subscribe the points as you would do for N4.2 or later stations).

NOTE: In N4.2, an action is available to force a re-fetch of n:history tag information. The action, Force Update Niagara Proxy Points, is on the following components: NiagaraNetwork, NiagaraStation, NiagaraStationFolder, NiagaraPointDeviceExt, and NiagaraPointFolder. This lets the you pick the level for which to force update of any descendant proxy points. When this action is invoked, it creates a job (ForceUpdateNiagaraPointsJob) and submits it to the JobService for processing. You can go to the JobService to see the progress of the job and retrieve a log of the results.

About adding Proxy Points to web charts

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