Changing default chart displays of parameters

You're likely already aware of the Historic Chart node, which is the definitive way of creating a custom chart to display one or more of your parameters. However, there is a more lightweight option for customising the default chart view which often gets overlooked. The "Chart" tab within the configuration of a parameter allows you to modify the chart style, aggregation of data, and other options:

With these settings, you can determine how the parameter data will be presented any time it's displayed as a chart (either in the default chart view, or by choosing "Historic data - Chart" from the workspace menu). This will be seen by anyone looking at these views; in fact, the only way they will be able to see the parameter charted in a different way will be to create their own custom chart with different configuration. This means it's a great way to present parameter data in the way that you choose.

Why would you want to modify the default chart view for a parameter? Some raw data may only make sense when aggregated or presented in a certain way. And while you could certainly present it any way you like in a custom chart, that still leaves the possibility of any authorised user clicking on the standard chart view instead of your custom chart.

For example, you may have parameter data that only makes sense when charted as a weekly maximum. By making this the default, you are ensuring that any user who clicks on the parameter will always see the data as you configured it. Before you make this change, the chart view of this parameter would have default data aggregation set to "Automatic", which means interpolated data with a dynamic data interval chosen to suit the date range:

After the change, the chart view of this parameter now has data aggregation customised as a weekly maximum:

Another more common example involves hidden data spikes. When shown with default chart configuration, this voltage data looks to be holding a consistent range (generally between 13.5V and 13.9V) on the 7-day chart:

But remember how the default data aggregation mode is "Automatic"? The 7-day range of the chart is being automatically interpolated at 10-minute intervals; this is generally a great way to view data (which is why it's the default), but in this case there is a drawback; it's hiding some spikes that we care about. So that we never miss these spikes, we can change the data aggregation mode to "Raw", which disables aggregation and displays all the values:

This simple change is enough to reveal some previously hidden spikes in the voltage values:

Note that choosing "Raw" data has it's drawbacks too; there may be a lot more values shown on the chart, which can slow things down depending on the resolution of the data. You may need to compromise on the range of the chart to get this extra granularity; for example, looking at only 24 hours of raw data instead of a week of interpolated data.

In this final example, we will show the opposite perspective; we want to configure a chart to hide data that would normally be shown. Specifically, if we have defined one or more state thresholds, the default configuration would be to show them

on the chart:

This will expose all state thresholds to users looking at charts, which may not be desired. In this example, we have a state threshold of 13.87V which should trigger an alarm, but the overly-dramatic threshold name would appear on the chart like this:

To avoid this off-putting threshold from appearing on the chart, the "State thresholds" option can be changed to "Hidden":

And this will result in the same chart, without the threshold appearing in red:

Use these simple but effective parameter configuration options to ensure that your default chart views always look exactly the way you want them to!