Chart cards draw data over time or across categories. Line, bar and area charts take a series (values over time); pie, scatter, histogram and heatmap take a table. This page lists the settings of each, with defaults. For where the data comes from, see Data sources and parameters.
Line, bar and area charts
Data
The Series slot takes up to 8 sources (+ Add another source). The usual source is Device readings over time (live): pick the device, up to 20 keys and the aggregate (avg by default; increase for counters). Each key becomes a series.
A bar chart can also draw one bar per row of a table (One bar per > Row of a table): the latest value per device, site or status. Then choose the Bar label column, the Bar value column, the Order (As the rows come, Largest first, Smallest first) and Most bars (1 to 100, default 30).
Series styling
Under Series, add a row per series to style it. The Series field matches a series by name; * matches every series, and an exact name wins over *. Up to 20 rows.
| Field | Values |
|---|---|
| Label | Up to 60 characters; ${name} stands for the series’ own name |
| Colour | A colour, or automatic from the theme palette |
| Unit, Decimals | Override the card’s value format for this series |
| Value axis | Left or Right. Put a series with another unit (% next to °C) on the right axis. |
| Stack group (bar, area) | Series with the same group stack on each other |
| Line | Solid, Dashed, Dotted; Line width (px) 1 to 8 |
| Points, Point shape, Point size (px) | Chart setting, on or off; circle, square, diamond, triangle; 1 to 12 |
| Fill, Fill opacity | None, flat or gradient; 0 to 1 |
| Hidden until clicked in the legend | The series starts hidden |
Chart settings
| Group | Settings and defaults |
|---|---|
| Lines (line) | Line shape: Smooth (default), Straight, Steps; Line width (px) 2; Points on every value off |
| Bars (bar) | Stack the series off; Bars: Columns or Horizontal bars; Bar width 70 % of the room for each bar; gap 2 px; corner radius 4 px |
| Area (area) | Stack the series off; Fill: None, Soft (default), Medium, Strong; Fill style: Fades to the baseline or Flat |
| Value labels | Off (default) or a value at each point or bar; thinned so labels never overlap |
| Axis | Start the value axis at zero (off for line, on for area: off lets small changes show); Grid lines; Y minimum, Y maximum (from the data); Y axis title; X axis title; Value ticks (about) 2 to 10 |
| Right axis | Right axis title, minimum and maximum. It appears when a series is set to the right axis. |
| Legend | When there are 2 or more (default), Top, Bottom, Left, Right, Off; Values in the legend: Latest, Minimum, Maximum, Average, Total |
| Tooltip | All series (default), Nearest point, Off; decimals; a total row for stacked series |
| Thresholds | Up to 10 Threshold lines: a horizontal line at a value with a label, colour, style and axis, for example a limit |
| Animation and zoom | Animate on load on; Drag to zoom the time axis on (line and area) |
Units reach the axis and the tooltip. Card buttons start with Full screen and Download data (CSV).
Zoom and select a range
On a line or area chart, drag across the chart to zoom in. The zoom is for you only and does not change the board window. Double-click or Reset zoom leaves it.
A chart can also set the board’s window from a dragged range: in the card’s actions, add When a range is selected on the chart > Set the time window. See Card actions and drill-down.
Compare with the previous period
Each source of a slot has Show the period just before (same length) under its time window. That source then reads the window of the same length that ends where the board’s window starts, for example last week when the board shows this week.
To compare this week with last week, put two chart cards side by side with the same source, and tick the option on the second one. A source that reads the previous period is not live; it refreshes on the card’s interval. The points keep their real times, so the two periods are not laid over each other on one time axis.
A Stat or Stat with trend card compares a number with the previous period through its Compare with slot (see Value cards).
Pie chart
Bind a table with a label column and a value column (for example Alarm counts by severity).
| Setting | Values and defaults |
|---|---|
| Layout | Pie (default), Donut, Donut with total (with Caption under the total); ring thickness 10 to 90 % (40) |
| Most slices | 2 to 20 (default 8). The smallest of the rest fold into one “Other” slice. |
| Order | Largest first (default), Smallest first, As the data |
| Text on slices | Off, Share (default), Value, Name, Name and share; inside or outside with a line. Slices under 4 % stay unlabelled. |
| Slice colours | Pin a colour to a slice by its label (up to 30) |
| Tooltip shows | Value and share, Value, Share |
A click on a slice can run actions (When a slice of the pie is clicked).
Scatter chart
Bind a table with an X column and a Y column. A Group column makes one series per distinct value (up to 8 groups). Options: point colour, size, shape and opacity; Trend line (least squares) per group; X and Y units, decimals and limits.
Histogram
Bind a table and choose the Value column. Bins 1 to 50 (empty = chosen from the number of values); range minimum and maximum; Bin edges with round numbers; Mark the mean, Mark the median.
Heatmap
Bind a table with an X column, a Y column and a Value column, for example hour of day by weekday. Colours: Low to high colour or Colour ranges; Scale minimum and Scale maximum (from the data); a value in each cell (hidden when cells are too small).
Troubleshooting
| The card says | Cause |
|---|---|
| “Bind a data series in this widget’s settings.” | The series slot is empty. |
| “No data for this period.” | The device sent nothing in the window, or the keys are misspelled. Check the device’s Telemetry tab. |
| A long window looks smoothed | Long windows read hourly or daily aggregates. Pick a shorter window for raw detail. |
| “Bind a table with label and value columns…” | A pie needs a table source, not a series. |