Initially, DMX512 was developed to control AC dimmer racks connected in series through DMX input and through channels. A complex addressing system was not envisaged.
With the advancement of technology and the emergence of LED fixtures with built-in dimming circuits, DMX inputs and through channels began to be integrated directly into the devices themselves. Devices, for example moving heads, have extensive functionality: from precise positioning and brightness control to gobo selection, color mixing, zoom, and other multi-component effects. Each function occupies a separate DMX channel. As a result, one moving head can consume more than a hundred channels for full control of its capabilities, and the standard 512 channels are exhausted with just a few devices.
DMX512 has other limitations:
No more than 32 load units are connected to one line. 32 units is the recommended limit and it can be changed when using splitters/boosters;
Operates at a speed of only 250 kilobits per second;
The maximum cable length is 300 meters;
The unidirectional nature of the protocol limits control, diagnostics, and monitoring capabilities of device status;
The DMX512 signal is susceptible to electromagnetic interference.
All this makes DMX512 insufficient for controlling a multitude of modern lighting devices. Nevertheless, today this protocol is used to control almost all lighting devices and effects, including those that appeared much later after its creation, although 40 years have passed.
Ethernet Protocols – DMX over Network Cable
Ethernet is a group of standardized technologies for packet data transmission over local and metropolitan networks. It uses cable connections and MAC addressing to identify devices, effectively removing the limitations of DMX512.
Ethernet significantly surpasses the capabilities of traditional DMX512 in professional stage lighting due to its key advantages:
Ethernet transmits data 40–400 times faster than DMX512, and its speeds are constantly increasing, which removes limitations on the number of channels transmitted over the network, providing room for scaling.
Ethernet uses inexpensive and easily installed cable, which simplifies the installation and certification of the entire lighting cable infrastructure.
Easy integration – many facilities already have existing Ethernet infrastructure.
High reliability – the star topology ensures significantly greater system resilience compared to the bus topology of DMX512. A cable break in a star network disrupts communication only between two objects, whereas in a bus topology it can paralyze the entire segment.
Interference resistance – the use of differential signaling ensures high resistance to interference.
Power over cable (PoE) – the ability to power low-power nodes directly through the cable according to the Power over Ethernet (PoE) standard simplifies installation.
DMX over Ethernet is transported over IP and possesses all the aforementioned advantages. Thus, the transition to Ethernet is driven by the need for more flexible, scalable, and interference-resistant control of modern lighting.
What does sACN stand for in lighting?
Streaming ACN (sACN), or ANSI E1.31, is a lighting protocol that transmits DMX data over UDP/IP Ethernet networks.
sACN, developed by members of the American association ESTA (Entertainment Services and Technology Association), is part of the extensive family of protocols ACN (Architecture for Control Networks), first described in the standard ANSI E1.17-2006.
ACN defines a modular network architecture that includes network protocols, a device description language (DDL), and interaction profiles. Originally designed to operate over UDP/IP, ACN functions in IP, Ethernet, and Wi-Fi networks, which ensures its flexibility and scalability.
The E1.31 standard uses the User Datagram Protocol, UDP, for streaming data from multiple sources to multiple recipients. The lack of acknowledgments means there is no guarantee of delivery for all packets, which is typical for real-time streaming protocols.
Versions of the Streaming ACN Protocol
The first standardized version of sACN, ANSI E1.31-2009, was approved by ANSI (American National Standards Institute) on May 4, 2009. It laid the foundation for transmitting DMX512 over Ethernet/IP networks using a subset of ACN protocols, defining data format, protocol, addressing, and basic network management principles.
A revision of the standard occurred with the release of ANSI E1.31-2016, approved on October 11, 2016. This version introduced synchronization frames, allowing multiple receivers to process DMX data from one controller simultaneously, and universe discovery frames, simplifying the setup and management of large network systems.
The latest edition to date, ANSI E1.31-2018, from November 7, 2018, details the mechanism for transmitting DMX512A packets over TCP/IP networks, covering format, protocol, addressing, and network management. The 2018 edition supports IPv6 and IPv4, and also describes a synchronization method to ensure precise simultaneous data processing by multiple receivers.
Release sACN and Draft sACN
Release sACN refers to the officially approved and published ANSI E1.31 standards. It is the Release versions, such as ANSI E1.31-2009, ANSI E1.31-2016, and ANSI E1.31-2018, that are characterized by maximum compatibility and functionality. They have undergone a full cycle of development, review, and approval.
Draft sACN refers to preliminary versions of the protocol that existed before final ANSI approval. These are versions that require refinement. Due to the potential presence of errors, minor differences, or inconsistencies with the final standard, Draft versions are generally not used in large projects.
The prevalence of both types of versions makes compatibility issues between Release sACN and Draft sACN relevant. Converters from the ArtGate, GigaJet, PowerGate, DALIGate families, and PixelGate LED drivers from Sundrax absolutely support both Release and Draft versions of sACN, providing flexibility when working with various equipment.
What is the difference between Art-Net and sACN?
In the Ethernet environment, two protocols compete for transmitting DMX512 data: Art-Net and sACN. Both use UDP packets to transport DMX data over Ethernet networks.
Art-Net has become the ubiquitous de facto standard. It originally supports the Remote Device Management (RDM) protocol, which allows for feedback from devices. However, precisely because of sending RDM commands and requests, Art-Net until recently primarily used broadcast transmission, which can lead to network overload and packet loss. Version Art-Net IV, released in 2016, supports unicast transmission of RDM data.
RDM, like sACN, was developed by ESTA and standardized as ANSI E1.20.
sACN surpasses Art-Net in scalability, supporting up to 65,535 DMX universes compared to 32,768 universes in Art-Net IV, while earlier versions of Art-Net were limited to fewer (for example, 256 in Art-Net II).
Alex Chomsky
Technical Director at Sundrax Electronics
“To avoid making the article infinitely long, the topics of the Art-Net protocol and the RDM protocol are covered in more detail in these articles, which I recommend reading:”
sACN is ideal for modern stage and architectural lighting systems, especially for large installations where synchronization accuracy and management of a large number of devices are critical factors, since this protocol:
Supports a huge number of universes (65,535).
Has a built-in priority system that allows multiple DMX data sources to control one universe, automatically selecting data with the highest priority. This reduces the likelihood of errors in shows, as the protocol is designed with redundancy in mind.
Offers high resilience, since multicast transmission does not burden the network as much as broadcast.
Synchronizes DMX512 universes, ensuring simultaneous data processing by multiple receivers under the control of one controller.
Although for small installations the difference between Art-Net and sACN may not be obvious, the absence of limitations from older versions of Art-Net (for example, 4 incoming and 4 outgoing ports per IP address) makes it the preferred choice for large-scale setups with a lot of equipment and in permanent installations such as theme parks.
Disadvantages of sACN
sACN E1.31 has its nuances. It does not include direct support for RDM. To transmit RDM data over sACN, a separate protocol must be used.
Effective work with an sACN network requires a higher level of technical knowledge (complexity of diagnostics, traffic management), which can be a barrier for small installations or users without extensive network experience.
sACN is not as widely used as Art-Net.
Connection Scheme
For clarity, below is a typical connection scheme using sACN:
Controller (for example, grandMA2) (IP: 192.168.1.10) → GigaJet20 Pro (IP: 192.168.1.1, 3 Ethernet ports, 1 SFP) → Lighting devices.
GigaJet20 Pro distributes data through 20 DMX ports to devices, for example, Device 1 (IP: 192.168.1.11, Universe 1) and Device 2 (IP: 192.168.1.12, Universe 2).
Multicast is used to optimize traffic.
Project Examples
🎭 Theatrical Production: In a theater with 100+ lighting devices, sACN with GigaJet20 Pro provided control through one controller. Fiber optic communication minimized data loss.
🎶 Nightclub: At a concert, GigaJet20 Pro synchronized 50 moving heads, ensuring precise execution of lighting effects.
Comparative Table
Parameter
Without GigaJet20 Pro (DMX512)
With GigaJet20 Pro (sACN)
Number of devices
Up to 32 on one line
Up to 20 isolated ports
Maximum universes
1
Up to 65,535
Transmission speed
250 kbit/s
Up to 1000 Mbit/s (Ethernet)
Interference resistance
Low (RS-485)
High (optics/Ethernet)
Cable length
Up to 300 meters
Up to 100 km (with fiber optics)
Power supply
Separate unit
PoE (Power over Ethernet)
Data Exchange via sACN Protocol
sACN supports multicast and unicast transmission. GigaJet20 Pro optimizes multicast thanks to its built-in gigabit switch and support for IGMP snooping, which reduces network load. The device also provides data backup, increasing reliability.
Multicast
Multicast in sACN is a data delivery method where devices subscribe to specific distribution groups, and the network directs the corresponding packet stream to them. This is ideal for lighting control, allowing one set of data to reach multiple lighting devices. Protocols like IGMP (for IPv4) and MLD (for IPv6) are used to organize these groups.
Unlike Art-Net’s broadcast transmission, where the controller sends a full packet to each device on the network (requiring each to decode the entire packet), multicast sACN works more neatly. The controller sends commands in sACN packets divided by DMX universes. Devices on the network “listen” only to the universes they are subscribed to. This reduces bandwidth usage and optimizes Ethernet network management.
Multicast sACN simplifies setup for the sender, eliminating the need to manually specify recipients’ IP addresses: DMX universe data is sent to multicast IP addresses. Nodes receive data seamlessly, even if their IP address changes, as reception depends on subscription to the multicast group.
Potential Multicast Issues
When using multicast sACN in an unmanaged network (where there is no support for IGMP snooping), switches will send packets to all ports. This leads to excessive traffic on each device, forcing them to expend computational resources filtering unnecessary data. This is not a problem with multicast itself, but a consequence of using it in an unsuitable network environment.
The “plug & play” concept for multicast sACN is limited. For effective and stable operation in networks of any scale, correct configuration of IGMP snooping on network switches is necessary.
Unicast
In unicast transmission, the controller and receivers must be in the same IP address range and operate in static IP mode. Receiving devices in a unicast network will only listen to traffic addressed directly to them.
There are devices that do not support multicast and require unicast transmission, working only with data sent exclusively to them.
The sACN standard allows unicast data transmission, especially considering that in the early stages of its implementation, there was widespread equipment that worked incorrectly with multicast. According to the ANSI E1.31 standard, receivers must process both multicast and unicast traffic, ensuring maximum flexibility and compatibility.
When scaling, unicast becomes inefficient, but it can help reduce network congestion in environments without proper multicast support.
Streaming DMX
DMX data for each universe is sent continuously, even in the absence of changes in channel values. This means that a missed message will be repeated within 50 milliseconds. Unlike non-streaming protocols, sACN constantly confirms the current state of devices, preventing them from “freezing”.
The update frequency for an sACN universe does not exceed 44 times per second (the maximum for DMX is 44 Hz, used to match the DMX512 protocol, but theoretically sACN is capable of more under suitable conditions). Although there is no minimum update time, the receiving device itself determines the inactivity of the source (for example, if there is no data for a minute) and can decide on further actions with the light (turning off, setting to a certain level, and other programmed scenarios).
Technical Director at Sundrax Electronics
“Additionally, you can read about transmitting DMX 512 very far via optical cable in this article”
sACN over WiFi
sACN works in any IP network, including Wi-Fi. However, Ethernet surpasses wireless technology in reliability and resistance to interference. The ideal option is a dedicated local network for sACN.
In Wi-Fi networks, the choice between multicast and unicast for transmitting sACN traffic depends on the network characteristics, the number of receivers, and performance requirements.
• Multicast is suitable for a large number of receivers with IGMP snooping and QoS, despite possible packet losses.
• Unicast is better for a small number of devices but does not scale in large installations.
For real-time lighting control, it is important to consider delays and security (especially in Wi-Fi), as well as to minimize packet losses to ensure smooth and accurate system operation.
Technical Director at Sundrax Electronics
“Read more about how to transmit light wirelessly here”
What are the types of priority?
In the sACN protocol (ANSI E1.31), a complex system of priorities is implemented, allowing effective management of data sources. There are two main approaches to prioritization: by port (Universe Priority) and by address/channel (Per-Address Priority).
This is a set of rules by which sACN receivers merge data from competing sources based on these priorities. This allows multiple controllers to work with the same devices.
In the professional lighting industry, such functionality is highly sought after when multiple consoles are involved, and it is important for the installation to work synchronously.
Universe Priority
Each sACN packet (with start code 0x00), transmitting levels for all 512 addresses of a DMX universe, contains one common priority ranging from 0 (lowest) to 200 (highest), with a default value of 100. All addresses in the universe have the same priority. Different universes from the same source can have different priorities.
sACN traffic receivers are not required to support multiple sources, but typically distinguish them by component identifier (CID). If multiple sources transmit data for one universe with different priorities, the receiver will always use levels from all 512 addresses from the source with the highest priority. This occurs even if the levels of individual channels from the source with higher priority are lower than those from a source with lower priority.
In cases where multiple sources have the same priority, receivers may use the Highest Takes Precedence (HTP) mechanism to merge levels of individual addresses. The number of parallel sources supported by the receiver may be limited. If the number of sources exceeds the limit, new sources, even with high priority, will be ignored.
Per-Address Priority
Per-Address Priority allows assigning individual priorities for each separate DMX address in a universe. These priorities are transmitted along with level packets (0x00), but in a separate packet with an alternative start code 0xdd, containing priority data for all 512 addresses. In this scheme, a priority of 0 means “ignore level data for this address.”
If multiple sources transmit levels for one address with the same per-address priority, HTP merging rules are applied, but only for that specific address.
Compatibility Features and Advanced Capabilities of sACN
The ANSI E1.31 sACN standard does not oblige devices to support or understand Per-Address Priority. Most devices operate only with Universe Priority, although some support Per-Address Priority, using Universe Priority by default, while others set and apply priority per address.
When devices with different priority support interact:
If a source sends data with Per-Address Priority, and the receiver supports only Universe Priority, the latter ignores the 0xdd packet (with per-address priorities) and uses exclusively the Universe Priority from the 0x00 packet. If the source is configured for Universe Priority, and the receiver for Per-Address Priority, the system functions as if both devices are operating in Universe Priority mode. In this case, the receiver does not need to process the 0xdd packet.
Removing Limitations with Sundrax Converters
, such as ArtGate Pro, significantly expand the capabilities of working with DMX streams, offering intelligent merging. Two DMX consoles can be connected to one device, and rules for combining their signals can be configured by choosing merging modes: HTP (Highest Takes Precedence), LTP (Latest Takes Precedence), AUTO, and PRIORITY.
The converters also support RDM (Remote Device Management), which allows remote configuration of lighting devices. If necessary, they filter the RDM protocol, reducing network load and increasing compatibility with devices that do not support RDM. The converters are compatible with all industry protocols.
Additional technical capabilities:
Primary/secondary universe backup;
Controlled merging by dedicated channel or universe;
Fixed IP addresses and easy access to configuration;
Fanless cooling, which prevents particles from entering the housing;
Maintaining operability at voltages up to 305 V.
ArtGate Pro is housed in a durable metal case weighing only 1.2 kg. Connection is made via a reliable
that supports daisy-chaining. This solution ensures durability and ease of installation, allowing the converter to be set up and immediately put to work without worrying about its reliability under intensive use.
