04 Advanced Variables

Multi-select, repeat panels, and hidden variables for per-machine OEE.

In this tutorial you'll build a dashboard that shows OEE metrics and production runs per machine. Panels repeat automatically for each selected machine:

What you'll learn

• Multi-select and "Include All" for variables

• Automatically repeating panels (Repeat)

• Hidden variables for time rounding (OEE API)

• Per-machine OEE with POST queries

• Brief overview: time series data via the API

Prerequisites

• Working with Variables completed

• Understanding of dashboard variables, JSONata, and API queries

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Multi-select and Include All

In Part 1 the machine variable held a single value. For a dashboard showing multiple machines at once, you need multi-select.

1. Create a new dashboard with a site variable as in Part 1

2. Create a variable machines (plural) with these settings:

Setting	Value
Variable type	Query
Name	machines
Label	Machine
URL	machines
Root selector	$.data

1. Add under URL Query Params:

Key	Value
site	${site}

1. Columns: name (Name), uuid (UUID)

2. Under Selection options:

   • Enable Multi-value

   • Enable Include All option

   • Sort: Alphabetical (asc)

   • Refresh: On dashboard load

You can now select individual machines from the dropdown or choose All for every machine at the site.

Note the variable name machines (plural). This signals that the variable can hold multiple values and avoids confusion with the single-value machine variable from Part 1.

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Repeating panels (Repeat)

Instead of creating separate panels for each machine, let Grafana repeat panels automatically.

Configure a row with Repeat

1. Create a Row (click Add > Row)

2. Click the gear icon on the row

3. Set Title to ${machines:text}

4. Under Repeat for: select the machines variable

Grafana now creates a separate row for each value of the machines variable. Within each row, ${machines} is replaced by the UUID of the respective machine.

Panels inside a repeat row automatically use the current iteration value. While ${machines} normally contains multiple UUIDs, inside a repeat row it resolves to exactly one UUID per iteration.

You can only edit the first repeated element — whether row or panel. The remaining copies are automatically regenerated from the first element on every refresh.

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Hidden variables: time rounding for OEE

The productivity-metrics endpoint expects timestamps aligned to 10-minute intervals. Grafana's built-in time variables (${__from}, ${__to}) return arbitrary timestamps. The solution: custom variables that round the selected time range to 10-minute intervals. Since these variables are only relevant for queries, they are implemented as hidden variables — they don't appear as dropdowns in the dashboard. If needed, you can include their value using ${start} or ${end} in panel titles for transparency.

Create the start variable

1. Open Dashboard Settings > Variables > + New variable

2. Configure:

Setting	Value
Variable type	Query
Name	start
Hide	Variable (fully hidden)
Source	Inline
Data	{"time": ${__from}}
Root selector	see below
Refresh	On time range change

1. Root selector (JSONata expression):

(
  $time_millis := $number($.time);
  $time_rounded := $time_millis - $time_millis % 600000;
  $fromMillis($time_rounded)
)

600000 milliseconds = 10 minutes. The formula rounds the timestamp down to the nearest 10-minute interval.

Create the end variable

Create a second hidden variable end with the same settings, but:

Setting	Value
Name	end
Data	{"time": ${__to}}

Refresh: On time range change is critical here. Without this setting, start and end would only be calculated when the dashboard loads and wouldn't update when you change the time range.

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Per-machine OEE with Repeat

Now you'll combine repeat rows with the productivity-metrics endpoint.

OEE Stat panel

Create a Stat panel inside the repeat row:

Setting	Value
Method	POST
URL	machines/${machines}/productivity-metrics
Root selector	$.data

Expand Parsing options & Result fields and add a Column:

Selector	Title	Type
productivity.score	productivity	Number

Expand URL options and configure the request body:

Setting	Value
Body Type	Raw
Body Content Type	JSON
Body Content	{"datetime_ranges": [{"start": "${start}", "end": "${end}"}]}

Make sure Body Content Type is set to JSON (not Text). The ENLYZE API rejects requests with Content-Type: text/plain (HTTP 422).

Configure the panel:

• Unit: Percent (0.0-1.0)

• Color mode: Background

• Thresholds: Red (base), Yellow (0.6), Green (0.8)

• Value Mapping: null → "NO DATA" (Grey)

Why Columns instead of Root Selector?

It would be tempting to extract the score directly in the root selector, e.g. $.data[0].productivity.score. This works as long as the API returns data. However, if a machine wasn't running during the selected time range, $.data is an empty array. Accessing [0] then fails and Grafana shows an error instead of an empty panel.

The solution: set the root selector to $.data and extract the value via a Column (productivity.score). If there's no data, the column returns null. You can then display this null value as "NO DATA" using a Value Mapping.

Additional OEE panels

Create panels for the remaining metrics using the same pattern:

Panel	Root selector	Column Selector
Availability	$.data	availability.score
Performance	$.data	performance.score
Quality	$.data	quality.score

Configure a value mapping for null → "NO DATA" in grey on all panels. Not all machines provide quality data, and machines without production in the selected time range show "NO DATA" for all metrics.

Production runs table

Add a Table to the row showing the production runs for the respective machine:

Setting	Value
Method	GET
URL	production-runs
Query Params	machine=${machines}, start=${__from:date:iso}, end=${__to:date:iso}
Root selector	$.data

Add columns: start (Start, Timestamp), end (End, Timestamp), production_order (Order, String), productivity.score (OEE, Number).

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Excursus: time series data via the API

For time series data (e.g. temperature curves, throughput) the ENLYZE API offers the timeseries endpoint:

POST /timeseries
{
  "machine": "uuid",
  "start": "2025-12-08T00:00:00Z",
  "end": "2025-12-09T00:00:00Z",
  "variables": ["variable-uuid-1", "variable-uuid-2"],
  "resampling_interval": 60
}

The resampling_interval parameter (in seconds) reduces the data volume. Without resampling, queries can return very large datasets.

Limitations:

• The API paginates responses (max 100 entries per page). The Infinity plugin only supports automatic pagination experimentally.

• For time series visualizations, the ENLYZE data source (the dedicated Grafana plugin) is the better choice, as it handles pagination and resampling automatically.

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Tips

• Variable Refresh: "On dashboard load" for master data (sites, machines). "On time range change" for time-dependent calculations like the rounded timestamps.

• Variable order: The order in Settings determines the evaluation order: site → machines → start → end.

• Debugging Repeat: If repeat panels don't appear, check that the variable is correctly selected under Repeat options on the row and that it contains multiple values.

• POST Body: The body is specified as a string. Variables like ${start} are replaced before sending. Ensure correct JSON syntax with quotes.

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Next steps

• Production Status Dashboard — Constant variables and live status displays for multiple machines