03 Variables

Use Grafana dashboard variables with ENLYZE data.

What You'll Learn

• Create dashboard variables for dynamic filtering

• Build site and machine dropdown selectors

• Chain variables so machine options depend on selected site

• Use variables in Infinity queries

• Create hidden helper variables

Prerequisites

• Completed Tutorial 4.1 and 4.2

• Understanding of Infinity queries and JSONata

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Overview

Dashboard variables create interactive dropdowns that let users filter data without editing queries. They're essential for:

• Site selection – Choose which location to view

• Machine selection – Filter to specific machines

• Time period selection – Custom date ranges

• Multi-user dashboards – One dashboard serves many needs

Variable Types

Type	Description	Use Case
Query	Values from API/database	Site, machine, product dropdowns
Custom	Fixed list of values	Shift names, status options
Text box	User-entered value	Search filters
Constant	Single hidden value	Base URLs, fixed IDs
Interval	Time intervals	Refresh rates

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Creating Your First Variable

Let's create a site dropdown that queries the ENLYZE API.

Step 1: Open Variable Settings

1. Open your dashboard

2. Click the gear icon (Dashboard settings)

3. Select Variables from the left menu

4. Click Add variable

[SCREENSHOT: Dashboard settings with Variables menu]

Step 2: Configure Basic Settings

Setting	Value
Name	site
Type	Query
Label	Site
Hide	(leave empty - show variable)

Important: Variable names should be lowercase with no spaces. Use underscores if needed (e.g., machine_uuid).

[SCREENSHOT: Variable basic settings]

Step 3: Configure Query

Under Query Options:

1. Set Data source to Infinity

2. Set Query type to Infinity

The query editor appears. Configure it like a panel query:

Setting	Value
Type	JSON
Parser	Backend
Source	URL
URL	sites
Root selector	$.data

[SCREENSHOT: Variable query configuration]

Step 4: Configure Value Mapping

Scroll down to Value options:

Setting	Value	Description
Regex	(leave empty)	Filter results
Sort	Alphabetical (asc)	Order options

The dropdown needs to know which fields to display and store:

• Display value: What users see (site name)

• Stored value: What's used in queries (site UUID)

For Infinity variables, the first column becomes the display value, and if there's a second column, it becomes the stored value.

To control this, add columns to your query:

1. Scroll to Columns in the query

2. Add two columns:

Selector	Title	Type
name	Name	String
uuid	UUID	String

[SCREENSHOT: Column configuration for variable]

Step 5: Preview and Save

1. Click Run query to preview values

2. Verify the dropdown shows site names

3. Click Apply to save

You should see the site dropdown at the top of your dashboard.

[SCREENSHOT: Site dropdown in dashboard]

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Using Variables in Queries

Now use the ${site} variable in panel queries.

Filtering Machines by Site

Create a panel that shows machines for the selected site:

URL:

machines

Root selector (JSONata filter):

$filter($.data, function($v){ $v.site = "${site}" })

This filters the machines array to only include those where the site matches the selected variable.

[SCREENSHOT: Panel showing filtered machines]

Variable Syntax

Syntax	Description	Example
${variable}	Basic substitution	${site}
${variable:raw}	No escaping	URL parameters
${variable:csv}	Comma-separated	Multi-select values
${variable:pipe}	Pipe-separated	Regex patterns

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Chained Variables

Create a machine dropdown that updates when the site changes.

Step 1: Create Machine Variable

Add a new variable:

Setting	Value
Name	machine
Type	Query
Label	Machine

Step 2: Configure Query with Filter

Use JSONata to filter machines by the selected site:

Setting	Value
Type	JSON
URL	machines
Root selector	$filter($.data, function($v){ $v.site = "${site}" })

Add columns:

Selector	Title
name	Name
uuid	UUID

Step 3: Configure Refresh

Critical: Set refresh behaviour so machine options update when site changes:

Setting	Value
Refresh	On dashboard load

[SCREENSHOT: Chained variable configuration]

Step 4: Test the Chain

1. Change the site dropdown

2. Verify machine dropdown updates to show only machines at that site

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Multi-Select Variables

Allow users to select multiple values.

Enabling Multi-Select

In variable settings:

Setting	Value
Multi-value	Enabled
Include All option	Enabled

[SCREENSHOT: Multi-select settings]

Using Multi-Select in Queries

Multi-select variables return multiple values. Handle them appropriately:

For URL parameters (comma-separated):

production-runs?machine=${machine:csv}

For JSONata filters:

$filter($.data, function($v){ $v.machine in [${machine:csv}] })

For regex matching:

$filter($.data, function($v){ $match($v.uuid, /${machine:pipe}/) })

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Hidden Variables

Some variables shouldn't be shown to users but are useful for queries.

Use Cases

• Convert time formats

• Store computed values

• Hold intermediate results

Creating a Hidden Time Variable

Create a variable that converts Grafana's time to ISO format:

Setting	Value
Name	start_iso
Type	Query
Hide	Variable (completely hidden)

Query configuration:

Setting	Value
Source	Inline
Data	{"time": ${__from}}
Root selector	$fromMillis($number($.time))

Setting	Value
Refresh	On time range change

This converts the epoch milliseconds from ${__from} to ISO format.

[SCREENSHOT: Hidden variable configuration]

Hide Options

Value	Behaviour
(empty)	Show label and value
Label	Show value only
Variable	Completely hidden

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Complete Example: Site > Machine Dashboard

Let's build a dashboard with chained site and machine dropdowns.

Variables to Create

1. site – Site dropdown

2. machine – Machine dropdown (filtered by site)

Variable 1: Site

Setting	Value
Name	site
Label	Site
Type	Query
Query URL	sites
Root selector	$.data
Columns	name, uuid
Sort	Alphabetical

Variable 2: Machine

Setting	Value
Name	machine
Label	Machine
Type	Query
Query URL	machines
Root selector	$filter($.data, function($v){ $v.site = "${site}" })
Columns	name, uuid
Refresh	On dashboard load

Using in Panels

Production Runs with OEE:

URL: production-runs?machine=${machine}&start=${__from:date:iso}&end=${__to:date:iso}
Root selector: $.data

This returns production runs for the selected machine with OEE scores (productivity, availability, performance, quality) per run.

Variables (Sensor Data) Query:

URL: variables?machine=${machine}

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Variable Display Options

Dropdown vs Radio Buttons

In variable Display settings:

Display	Description	Best For
Dropdown	Standard select	Many options
Radio	Horizontal buttons	Few options (2-5)

Custom All Value

When "Include All" is enabled, you can customize what value "All" represents:

Setting	Value	Result
Custom all value	.*	Regex match all
Custom all value	$__all	All selected values

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Troubleshooting Variables

Variable Shows No Values

Causes:

1. Query returns no data

2. Wrong root selector

3. Columns not configured

Fix: Test the same query in a panel first.

Chained Variable Not Updating

Causes:

1. Refresh not set correctly

2. Parent variable name typo in filter

Fix: Set Refresh to "On dashboard load" and verify variable name in JSONata expression.

Multi-Select Returns Wrong Format

Cause: Not using proper format modifier

Fix: Use ${variable:csv} for comma-separated or ${variable:pipe} for pipe-separated.

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Best Practices

Naming Conventions

• Use lowercase: site, not Site

• Use underscores: machine_uuid, not machineUuid

• Be descriptive: production_line, not pl

Performance

• Filter data in variables, not just in panels

• Use "On dashboard load" refresh for dependent variables

• Avoid excessive API calls with proper caching

User Experience

• Use meaningful labels

• Set sensible defaults

• Hide technical variables from users

• Order variables logically (site -> machine -> variable)

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Summary

You've learned to create dynamic dashboards with variables:

• Query variables from the ENLYZE API

• Chain variables for dependent dropdowns

• Use variables in Infinity queries with ${variable} syntax

• Create multi-select and hidden helper variables

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What's Next?

Continue with:

• Production Status Dashboard – Build a complete multi-machine overview

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Quick Reference

Variable Query Settings

Setting	Value
Type	Query
Data source	Infinity
Query type	Infinity
Parser	Backend

Common Root Selectors

Purpose	JSONata Expression
All items	$.data
Filter by site	$filter($.data, function($v){ $v.site = "${site}" })
Filter by machine	$filter($.data, function($v){ $v.machine = "${machine}" })

Variable Modifiers

Modifier	Output	Use Case
${var}	Single value	Most queries
${var:csv}	a,b,c	URL parameters
${var:pipe}	a|b|c	Regex patterns
${var:raw}	Unescaped	Special characters

Refresh Options

Value	When
Never	Only on page load
On dashboard load	When dashboard opens
On time range change	When time picker changes