Isadora’s ArtNet Send and ArtNet Receive actors allow DMX lighting data to be sent and received over a computer network using the Art-Net protocol.

This article explains how Art-Net addressing works in Isadora, including how the actor’s universe input relates to the AN subnet and AN universe values shown on the actor.

It is intended for users who are new to DMX and Art-Net, so no previous lighting-network experience is required.

Using more than four Art-Net universes?
Some versions of Isadora’s ArtNet actors have a known limitation when using more than four universes at the same time. See [Known Issue: Using More Than Four Art-Net Universes in Isadora] for the affected versions and workaround.

What Is DMX?

DMX is a standard commonly used to control theatrical lighting, LED fixtures, dimmers, moving lights, and other show equipment.

A single DMX universe contains up to 512 channels.

Each lighting fixture uses one or more of these channels. For example:

• A simple dimmer might use one DMX channel.

• An RGB light may use three or more channels.

• A moving light may use many channels for intensity, colour, position, focus, and other functions.

If your system requires more than 512 channels, you can use additional DMX universes.

You may also choose to use separate universes simply to organize different groups of equipment.

For example:

• Universe 1: stage lighting

• Universe 2: scenic lighting

• Universe 3: LED fixtures

• Universe 4: practical lighting or special effects

What Is Art-Net?

Traditional DMX is commonly carried over dedicated DMX cables.

Art-Net allows DMX data to be sent over an Ethernet network.

A simple system might look like this:

Isadora → Ethernet Network → Art-Net/DMX Interface → Lighting Fixtures

Art-Net can also be exchanged directly between compatible applications or lighting consoles.

For example:

Lighting Console → Art-Net Network → Isadora

or:

Isadora → Art-Net Network → Lighting Software

In Isadora:

• ArtNet Send sends DMX data from Isadora.

• ArtNet Receive receives DMX data into Isadora.

For communication to work, the sender and receiver must be configured for the same Art-Net address.

Understanding Universes in Isadora

Both the ArtNet Send and ArtNet Receive actors have an input called:

universe

This is the main value you use to choose the Art-Net universe for that actor.

Isadora converts this number into two Art-Net values:

• AN subnet

• AN universe

These values appear as outputs on the actor.

For example:

You do not need to calculate these values manually in most cases. Isadora does the conversion for you.

The important pattern is:

• Isadora universes 0–15 use Art-Net subnet 0

• Isadora universes 16–31 use Art-Net subnet 1

• Isadora universes 32–47 use Art-Net subnet 2

• Isadora universes 48–63 use Art-Net subnet 3

Each group of 16 values moves to the next Art-Net subnet.

Why Are There Both a Subnet and a Universe?

Art-Net divides its addressing into several parts.

For everyday use in Isadora, the two values you will usually see are:

• AN subnet

• AN universe

You can think of the subnet as a group containing up to 16 Art-Net universes.

For example:

Subnet 0

Contains:

AN universe 0–15

which corresponds to Isadora:

universe 0–15

Subnet 1

Contains:

AN universe 0–15

which corresponds to Isadora:

universe 16–31

Subnet 2

Contains:

AN universe 0–15

which corresponds to Isadora:

universe 32–47

Isadora combines these two values into the single universe input to make patching easier.

Zero-Based Numbering

Isadora uses zero-based numbering for its Art-Net universe input.

That means:

Isadora universe 0 is the first available universe.

This is common in software, but it can be confusing because some lighting consoles and hardware devices display their first universe as:

Universe 1

As a result, you may sometimes encounter situations where:

• Isadora calls an address 0

• another device calls that same first universe 1

This does not necessarily mean that the devices are configured differently. It may simply be a difference in how the user interface numbers universes.

If you are unsure, compare the actual:

• AN subnet

• AN universe

values on both devices.

Matching Isadora to Another Art-Net Device

The most important rule when configuring Art-Net is:

The sender and receiver must be using the same Art-Net address.

For example, suppose your ArtNet Send actor uses:

universe = 17

Isadora will display:

AN subnet = 1
AN universe = 1

Your receiving lighting device, software, or Art-Net node must be configured for the corresponding Art-Net address.

If the receiving device allows you to enter subnet and universe separately, use:

Subnet 1, Universe 1

If it instead uses a single combined universe number, check that product’s documentation to determine how it represents Art-Net addresses.

Different manufacturers do not always display Art-Net addressing in exactly the same way.

Using ArtNet Send

The ArtNet Send actor sends DMX values from Isadora onto the network.

For a basic setup:

1. Add an ArtNet Send actor to your Scene.

2. Set the universe input to the Art-Net universe you want to transmit.

3. Leave node name blank to broadcast Art-Net, or select a discovered Art-Net device.

4. Normally, leave intf addr blank unless you need to select a specific network adapter.

5. Supply DMX data to the actor.

6. Confirm that the ready output is on.

When:

ready = on

the actor has initialized successfully and is ready to send Art-Net data.

What Does ready Mean?

The ready output tells you that the ArtNet Send actor was successfully created and is prepared to transmit.

It does not confirm that another device is actually receiving the data.

If ready is on but your lighting equipment is not responding, check:

• the receiving device’s Art-Net address,

• the DMX channel numbers being sent,

• the selected network interface,

• your computer’s network connection,

• and any firewall or network configuration that may be blocking communication.

Using ArtNet Receive

The ArtNet Receive actor receives DMX data from another Art-Net transmitter.

For a basic setup:

1. Add an ArtNet Receive actor.

2. Set its universe input.

3. Enter the DMX channels you want to receive in the channels input.

4. Confirm that the active output is on.

5. Watch the data rcv output to confirm that Art-Net packets are arriving.

For example, entering:

1-8

into the channels input creates outputs for DMX channels 1 through 8.

You can also enter individual channels or groups, such as:

1-4,10,15-20

What Does active Mean?

When:

active = on

the ArtNet Receive actor has initialized successfully and is ready to receive Art-Net data.

This does not necessarily mean that data is currently arriving.

The:

data rcv

output sends a trigger whenever new Art-Net data is received.

If active is on but data rcv never triggers, check:

• that another device is transmitting Art-Net,

• that it is transmitting on the matching Art-Net address,

• that your network connection is correct,

• and that Isadora is using the correct network interface.

Choosing a Network Interface

Both ArtNet Send and ArtNet Receive include an input called:

intf addr

This determines which network interface Isadora uses for Art-Net communication.

For most users, the best starting point is to leave this input blank.

Isadora will select a network interface automatically and display its IP address at the intf addr output.

You may need to specify an interface manually if your computer has several network connections, such as:

• Ethernet and Wi-Fi at the same time

• multiple Ethernet adapters

• USB network adapters

• virtual network adapters

If Art-Net is being sent or received on the wrong network, check the intf addr output first.

Broadcast, Node Name, and IP Address

The ArtNet Send actor provides several ways to choose where the data is sent.

Leave node name Blank

When node name is blank, Isadora broadcasts Art-Net on the selected network interface.

This can be useful for simple systems where one or more Art-Net devices are listening on the same network.

Select a Discovered Node

Art-Net devices on the network may appear in the node name pop-up menu.

Selecting one of these devices allows Isadora to direct data to that discovered Art-Net node.

Enter an IP Address

You can also enter the IP address of an Art-Net device directly.

For example:

2.0.0.20

This can be useful when you know exactly which device should receive the Art-Net data.

A Simple Addressing Example

Imagine that you have three groups of lighting:

• stage lighting

• scenic lighting

• LED fixtures

You could use:

Each ArtNet Send actor would use one of these universe values.

The receiving devices would then be configured to listen for the matching Art-Net address.

Crossing Into the Next Subnet

Suppose you need more than 16 Art-Net universe addresses.

After:

universe = 15

the next value is:

universe = 16

At this point Isadora changes from:

AN subnet 0, AN universe 15

to:

AN subnet 1, AN universe 0

The numbering therefore looks like this:

This is normal Art-Net addressing.

Troubleshooting Addressing Problems

If Art-Net communication is not working, start with the addressing before changing more advanced network settings.

Check the Isadora Universe

Confirm the value entered in the actor’s:

universe

input.

Then look at:

• AN subnet

• AN universe

These show the Art-Net address Isadora is actually using.

Check the Other Device

Confirm that the lighting console, Art-Net interface, node, or application is configured for the same address.

Be especially careful about:

• zero-based versus one-based universe numbering,

• devices that display subnet and universe separately,

• and devices that combine the values into a single universe number.

Check the Actor Status

For ArtNet Send:

ready = on

For ArtNet Receive:

active = on

If the actor itself is not ready or active, resolve that issue before troubleshooting the receiving equipment.

Check the Network Interface

Look at the actor’s:

intf addr

output.

Make sure Isadora is using the network connection attached to your Art-Net equipment.

This is particularly important on computers that are connected to both Wi-Fi and Ethernet.

Using More Than Four Universes

Some versions of Isadora’s ArtNet actors have a known limitation when more than four Art-Net universes are used simultaneously.

This limitation affects the numbering pattern that must be used and is not part of normal Art-Net addressing.

If your project requires more than four DMX universes, see:

[Known Issue: Using More Than Four Art-Net Universes in Isadora]

That article explains:

• which actor versions are affected,

• how to recognize the issue,

• the required addressing workaround,

• and how to update existing projects when corrected actor versions become available.

Quick Reference

One DMX universe contains

Up to 512 DMX channels

ArtNet Send

Sends DMX data from Isadora over the network.

ArtNet Receive

Receives DMX data into Isadora.

Isadora universe

Selects the Art-Net address used by the actor.

AN subnet and AN universe

Show how Isadora has converted the universe input into the Art-Net address.

First Isadora universe

0

Isadora universe 16

AN subnet 1
AN universe 0

ArtNet Send status

ready = on

ArtNet Receive status

active = on

Most important troubleshooting rule

Make sure the sender and receiver are using the same Art-Net address.