Radial gauge

Who it’s for

Anyone who wants a reading presented as a real instrument — a dial with a needle, a printed scale and colored bands — rather than as a modern flat arc. Control-room mimics, plant panels and demo dashboards all reach for this look because it matches the equipment operators already know.

What it does

The Radial gauge draws a value as a needle sweeping a scaled dial, with a digital value box beneath it. The default −100 to 100 scale sweeps 270 degrees starting at 45, with major and minor tick marks, a units caption, and a seven-segment style readout in the box, so the dial reads as an instrument rather than as a chart element.

• A needle on a printed scale — position, direction of travel and the ticks it is between are all readable at once.
• Colored highlight bands mark regions of the scale, which is how a normal, warning and danger zone are shown without changing the needle.
• The digital value box gives the exact number, so the dial does not have to be read precisely.
• Plate, border, needle, ticks and fonts are all styled independently, which is what makes the instrument look deliberate rather than default.
• Animation with a choice of easing rules moves the needle rather than jumping it, matching how a physical gauge behaves.
• Units are converted, not just appended — the gauge respects the unit set on the key and converts to the unit chosen on the widget.
• The Radial gauge shows one current reading: it plots no history, and it is the analogue counterpart of the flat Gauge rather than a different measurement.

How to set up

Data keys

The Radial gauge takes one datasource, one entity and one data key.

Key	Role	Type	Description
Any numeric key	The value the needle points to	Timeseries	Numeric only. An attribute works equally well. The key’s own units and decimals override the widget-level ones.

Scale

Setting	Default	Effect
Ticks min / max	-100 / 100	The ends of the scale
Major ticks count	Auto	How many labelled divisions the scale carries
Minor ticks count	10	Unlabelled subdivisions between the major ticks
Highlights	None	Colored bands drawn on the scale for normal, warning and danger regions
Start ticks angle	45	Where the scale begins, in degrees
Ticks angle	270	How far the scale sweeps
Units title	On	The caption printed on the dial

Set the range to what the equipment can actually do, then place the highlights at the limits that matter. The scale’s whole purpose is to give a number a position, and both the range and the bands have to be real for that position to mean anything.

How to customize

• To mark normal, warning and danger regions — add Highlights bands at the values that separate them, and set the band width.
• To fit a wider or narrower dial — adjust Start ticks angle and Ticks angle, which together decide how much of the circle the scale uses.
• To make the scale easier to read — set Major ticks count so the labelled divisions land on round numbers, and adjust the minor ticks between them.
• To drop the digital readout — turn off Value box, leaving a purely analogue instrument.
• To style the instrument — set the Plate color, Plate border, needle gradient colors and needle circle size.
• To caption the dial — set Units title and the units text, with their own fonts and colors.
• To change how the needle moves — set the Animation duration and easing rule, or turn animation off.

Tips

• Choose the major tick count so the labels are round numbers. A −100 to 100 scale divided into seven produces labels nobody can read at a glance, and the whole advantage of a printed scale is lost.
• Use highlights rather than a value-following needle color. On a physical instrument the bands are painted on the dial and the needle stays one color, and readers apply that expectation whether or not anyone told them to.