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Bar Chart

Bar chart widget

The Bar chart widget visualizes discrete or aggregated data values over time using vertical bars. It supports real-time updates, multiple series, data aggregation, thresholds, and comparison mode — making it ideal for comparing metrics like daily energy consumption, device activity per hour, or production counts across time intervals.

  • Multiple data series with independent colors and Y axis assignments.
  • Real-time and history modes with configurable time window and data aggregation (average, sum, min, max, count).
  • Comparison overlay: plot the same series from a previous period (yesterday, last week, etc.) alongside current data.
  • Configurable thresholds as horizontal reference lines with labels and custom styles.
  • Legend with per-series statistics: min, max, average, total, and latest.
  • Bar width strategy for non-aggregated data: group bars side by side or render them separately.
  • Data zoom for inspecting narrow time ranges without changing the dashboard time window.
  1. Open the dashboard in edit mode. Click Add widget in the top toolbar, or click the Add new widget icon in the center of an empty dashboard.
  2. In the widget bundle selection dialog, find and click Charts.
  3. Select the Bar chart widget.
  4. Configure the datasource, series, and appearance, then click Add.

All settings in this section use Basic mode — a quick-start configuration covering the essentials. For finer widget controls like custom tooltip functions and advanced axis formatting, switch to the Advanced tab.

The Basic tab groups settings into: Time window, Datasource, Series, Y axes, Thresholds, Appearance, Chart, X axis, Bar width strategy for non-aggregated data, Legend, Tooltip, Animation, and Card appearance.

Define the time interval to display, like Last 7 days or Current month. Enable data aggregation to summarize values over specific intervals, like daily sums. Learn more in the Time window guide.

Select the source of telemetry data:

  • Device — a specific device; shows telemetry series from this device over the configured time range.
  • Entity alias — a set of entities matched by an entity alias; use this to compare metrics from multiple devices on the same chart.

The widget supports two display modes: Series and Comparison.

Each data key is rendered as an independent bar series. Add a key for each telemetry value to display, like energyConsumed or temperature. Each series updates dynamically as new telemetry arrives.

Click the settings icon on a series row to open the Data key configuration dialog with General and Advanced tabs.

General tab:

Setting Description
Key Telemetry or attribute key name.
Label Legend label for this series.
Units Unit suffix, like kWh or °C.
Decimals Decimal places for displayed values.
Color Bar color.
Use data post-processing function Optional JavaScript transform applied to the raw value before display. Signature: f(value, latestData).

Advanced tab — Legend:

Setting Description
Show in legend Include this series in the chart legend.
Hidden by default Series is rendered but hidden in the legend until toggled by the user.

Advanced tab — Y axis: Select which Y axis this series is plotted against.

Advanced tab — Tooltip value format function: Optional JavaScript function f(value, latestData) to format the value shown in the hover tooltip for this series.

Advanced tab — Comparison settings: Enable Show historical data for comparison to plot a comparison bar series from a previous time period alongside this series. Configure Comparison key label (auto or custom) and Comparison data color.

In Comparison mode, the widget overlays the same data keys from a previous time period on top of the current data — for example, this week vs. last week or today vs. yesterday. Each period is rendered as a separate bar series, making it easy to spot trends or anomalies across intervals.

Switch to the Comparison tab in the Series section to enable this mode. Each comparison entry has an interval dropdown, an X axis button, and a list of data keys (Show, Key, Label, Color).

Comparison interval options:

Option Description
Previous interval (default) Shifts the time window back by one full interval length.
Day ago Compares with the same period from 24 hours earlier.
Week ago Compares with the same period from 7 days earlier.
Month ago Compares with the same period from one month earlier.
Year ago Compares with the same period from one year earlier.
Custom interval Enter a custom offset in milliseconds.

Comparison X axis settings — click the X axis button to configure how the comparison time axis is displayed:

Setting Description
Show Display the comparison X axis on the chart.
Label Text label for the comparison axis.
Position Top or Bottom.
Tick labels Show date/time labels on ticks. Configure font and color.
Show ticks Render tick marks on the axis.
Show line Render the axis baseline.
Show split lines Render vertical grid lines for each tick.

Configure one or more Y axes to control vertical scaling and labeling. Each series can be assigned to a different axis via its Y axis field in the series settings. Click Add Y axis to add a new axis.

Each axis row shows the following columns:

Column Description
Id Unique identifier used to assign series to this axis.
Show Toggle axis visibility on the chart.
Label Text label shown next to the axis.
Position Left or Right.
Min / Max Fixed scale bounds. Leave empty for auto-scaling.
Units Unit suffix for axis tick labels.
Decimals Decimal places for tick label values.

Click the settings icon on an axis row to open the Y axis settings dialog:

Setting Description
Label Text label with configurable font and color.
Tick labels Show value labels on each tick. Configure font and color.
Show ticks Render tick marks on the axis line.
Show line Render the axis baseline.
Show split lines Render horizontal grid lines across the chart for each tick.
Ticks interval Interval between ticks. Auto derives it from the data range.
Split number Suggested number of tick intervals. Auto lets the chart decide.

Scale limits — set explicit minimum and maximum bounds for the axis scale. Each bound has a Source:

Source Description
Constant Fixed numeric value entered directly.
Key Value taken from a telemetry or attribute key of the current entity.
Entity Value taken from a specified entity’s attribute or telemetry key.

Add horizontal reference lines to mark safe, warning, or critical levels. Click Add threshold to add a row.

Column Description
Source Constant — a fixed numeric value. Entity — value pulled from an entity attribute or telemetry key.
Key / Value The numeric value (Constant) or the attribute/telemetry key name (Entity).
Y axis Which Y axis the threshold is drawn against.
Color Threshold line color.
Units Unit suffix displayed in the threshold label.
Decimals Decimal places for the threshold label value.

Click the settings icon on a threshold row to open the Threshold settings dialog:

Setting Description
Label Toggle to show a text label on the threshold line. Set position: Start, Middle, End, Inside start, Inside start top, or Inside start bottom. Configure font and color.
Label background Show a filled background behind the label text.
Line color Color of the threshold line.
Line type Dash style: Solid, Dashed, or Dotted.
Line width Stroke width in pixels.
Start symbol Marker at the left end of the line, like None or Arrow. Set symbol size.
End symbol Marker at the right end of the line, like None or Arrow. Set symbol size.

Controls the chart title displayed in the widget header.

Setting Description
Title Text shown in the widget header. Configure font, size, weight, and color.
Card icon Optional icon displayed next to the title.

Controls interactive behavior and chart area layout.

Setting Description
Data zoom Enable horizontal zoom for inspecting narrow time ranges without changing the dashboard time window.
Grid Adjust padding inside the chart area.
Stack mode Accumulate multiple series on the same axis, useful for showing contribution totals.

Configure the horizontal time axis. Use the Show toggle to hide the axis entirely.

Setting Description
Label Text label displayed along the axis. Configure font and color.
Position Bottom or Top.
Tick labels Show date/time labels on each tick. Configure date format, font, and color.
Show ticks Render tick marks on the axis. Configure color.
Show line Render the axis baseline. Configure color.
Show split lines Render vertical grid lines across the chart for each tick.

Bar Width Strategy for Non-Aggregated Data

Section titled “Bar Width Strategy for Non-Aggregated Data”

Controls how bar series are rendered when no data aggregation is applied.

Option Description
Group Bars for different series are placed side by side at each timestamp.
Separate Each series renders its bars independently, allowing overlap.

Use the master toggle to show or hide the legend entirely.

Setting Description
Position Legend placement: Top, Bottom, Left, or Right.
Show values Statistics displayed per series: Min, Max, Average, Total, Latest. Multiple values can be enabled simultaneously.
Label Font and color for series name labels.
Value Font and color for statistic values.
Column title Font and color for the column header row (visible when Show values is enabled).
Sort datakeys in legend Sort series entries alphabetically.

Use the master toggle to show or hide the tooltip entirely.

Setting Description
Trigger Point — hover over a data point; Axis — hover anywhere on the chart shows values for all series at that timestamp.
Date Toggle to show the timestamp. Select the date format and configure font and color.
Show date time interval Display the time interval range in the tooltip header.
Hide zero values Suppress series entries with a value of zero from the tooltip.
Show total value in stack mode Show the summed total of all series when Stack mode is enabled.
Label Font and color for series name labels in the tooltip.
Value Font and color for value text in the tooltip.
Background color Tooltip background fill color.
Background blur Blur radius (px) applied to the tooltip background.

Use the master toggle to enable or disable chart animation. When enabled:

Setting Description
Animation threshold If the number of data points exceeds this value (default 2000), animation is disabled to maintain performance.
Animation duration Duration of the initial load animation in milliseconds (default 500 ms).
Animation easing Easing function for the initial animation, like cubicOut.
Animation delay Delay before the initial animation starts, in milliseconds.
Update animation duration Duration of the animation when data updates arrive (default 300 ms).
Update animation easing Easing function for update animations.
Update animation delay Delay before update animations start, in milliseconds.
Setting Description
Background Solid color or image background for the card.
Show card buttons Enable Fullscreen and Data export toolbar buttons.
Card border radius Corner rounding in pixels.
Card padding Spacing between content and card border.

The Bar chart supports the Widget header button action — a button placed in the widget header that triggers a configured action when clicked.

Goal: Display daily energy consumption from a Smart Device on a bar chart for the last 7 days, aggregated as a daily sum.

Prerequisites: A device named Smart Device that sends energyConsumed (kWh) as a telemetry key.

Step 1. Add the widget. Open your dashboard in edit mode, click Add widget, select the Charts bundle, then choose Bar chart.

Step 2. Configure the time window. Set Period to Realtime — last 7 days, Aggregation to Sum, and Grouping interval to 1 day.

Step 3. Configure the datasource. Set Datasource type to Device, then select Smart Device.

Step 4. Add a series. In the Series section, add one data key:

Key Label Y axis Color Units Decimals
energyConsumed Energy Consumed default #4E79A7 kWh 1

Step 5. Configure Y axes. Set the default axis:

ID Label Position Units Decimals
default Energy, kWh Left kWh 0

Step 6. Configure appearance and legend. In the Appearance section set Title to Daily Energy Consumption, font size 18 px, weight 600. In the Legend section set Position to Bottom and enable Total.

Step 7. Disable data zoom. In the Chart section, disable Data zoom.

Step 8. Save. Click Add, resize and reposition as needed, then click Save on the dashboard toolbar.

Result: The chart displays one blue bar per day representing the total energy consumed. The legend shows the cumulative total across all displayed days. The chart updates automatically as new telemetry arrives.

Widget Shows No Data

Cause Solution
Wrong data key name Confirm the key name matches the telemetry key sent by the device. Key names are case-sensitive.
Incorrect datasource or entity alias Verify the correct Device or Entity alias is selected. Open Entity aliases to confirm the alias resolves to results.
Device not sending data Open Devices → Latest telemetry and check for recent values. If empty, verify the device transport configuration and access token.
No telemetry in the selected time window Extend the time range or switch to Realtime mode to confirm data exists.
Rule chain misconfiguration Check that the Rule Chain has a Save time series node routing device telemetry to the database.
Datasource updated after import After importing a widget, update the datasource to point to your device and update data key names to match your device’s actual telemetry keys.

Data Updates Stop or Show Partial Data

Cause Solution
Time window type mismatch Use Realtime for live monitoring, History for fixed date ranges.
Aggregation interval too large Reduce the grouping interval, like from 1 month to 1 day, for finer granularity.
Browser time zone mismatch Ensure the dashboard and device use the same time zone.

A Series Does Not Appear on the Chart

Cause Solution
Data key not added Open the Series section and confirm the telemetry key is added as a data key row.
Series hidden by default Open the data key’s Advanced settings and disable Hidden by default.
Wrong Y axis assignment Check that the series is assigned to an existing Y axis ID.