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Reference Lines

All chart-type widgets in TagoIO can be configured to display reference lines within the graph. These lines can serve as thresholds, upper and lower bounds, medians, or any other value that enhances the data visualization experience.

Supported widgets​

The widgets that support this feature include the Area Chart, Line Chart, Horizontal Bar, Vertical Column, and Multiple Charts.

Adding reference lines to your chart​

You can set reference lines by navigating to your widget's edit page and accessing the Reference Lines option.
Up to 5 reference lines per widget are allowed.

Defining a new line​

  1. Click Add Reference Line (or the equivalent button in the UI).
  2. Choose the source of the value:
    • Fixed – Enter a static numeric value that will be displayed as a horizontal or vertical line.
    • Variable – Select one of your device’s variables; the line’s value will update dynamically based on that variable.

Fixed vs Variable source​

  • When using a fixed source, you can manually set a Label and Color for the line.
  • If the source is a variable, the label and color are automatically taken from the variable’s metadata. For more information about how to configure metadata, see the Metadata article.

Multiple axes​

If your chart uses multiple Y‑axes, you can associate a reference line with a specific axis by clicking the axis icon inside the reference line options and selecting the desired axis. This ensures the line aligns correctly with the chosen scale.

Applying formulas​

You can apply a formula to the reference line’s value. This is especially useful when:

  • The dataset variables already have a Formula applied, or
  • You want to use a Dynamic Formula for custom unit conversions.

The formula will be evaluated each time the chart refreshes, keeping the reference line in sync with your data.