ESTA, the full name of Entertainment Services & Technology Association, is a non-profit business organization. Its members include dealers, manufacturers, service providers, manufacturers, stage venues, designers and consultants. The ESTA Association can help solve some of the issues that are of general concern, such as technical standards, customer service, product quality, business practices, insurance and credit reporting. And ESTA also provides a wide range of services to its members in terms of training and information exchange, membership upgrades, attendance at exhibitions, cost reduction and financial assistance.
The ACN Advanced Network Control Protocol is a standard set by the Network Control Protocol Group of the ESTA Organization Standards Office, which allows different manufacturers' lighting control devices to communicate and operate with each other. This is the most common protocol that can be applied to any network that supports the TCP/IP protocol, and is most commonly applied to Ethernet networks. This project has not yet been approved, but most of the protocol standards have been roughly written, and manufacturers from all over the world have also created prototypes of lighting network equipment to support the early passage of the ACN protocol.
[What should ACN Advanced Network Control Protocol do?]
To explain what ACN should do, let's first assume a situation. Assume that there is a 500 i dimming station from A manufacturer, a 2008H dimming station from B manufacturers, T1000 lamps from 40 C manufacturers, and D96plus 6K 96-channel dimming cabinets from 6 D manufacturers. Connect these devices to an Ethernet network and power them up. After a short period of time, the dimmer can see the working status of all the devices in the network, and the dimming station will ask the dimming personnel some questions through interactive devices such as screens. This allows the dimmer's operation of the 40 T1000 lamps and the D96plus 6K 96-channel dimming Cabinet to be quickly reflected on the 500 i and 2008H dimming stations. Soon the dimmer can operate hundreds of parameters on the dimming station, and some of these operations are independent, and some are operated by two dimming stations.
Further assume that if a series of previews are performed, it is found that two dimmers, two dimming stations, are not required. Just one is enough to operate this show. The field data on one dimming station can be transferred to another dimming station for control. The extra dimming station can be put back into the storage room.
What are the operations that the dimming staff do not have to do? they:
It is not necessary to set up a conversion network between multiple devices. It is not necessary to install an address switch on each device. It is not necessary to assign a control loop to the controller's DMX address. There is no need to worry about which device can only operate in which DMX area. It is not affected by 8-bit data. Device performance does not require manual editing of the field after removing the second dimming station. This example is primarily intended to give users an idea of ​​the benefits of using an ACN (ACN) system. Current dimming systems do not provide all of these features. Some of these features can be achieved by some manufacturers' network control products, but only when the same manufacturer's products are applied to a network. Products from different manufacturers cannot communicate with each other unless they pass USITT's DMX512/1990 standard, but it can only provide some lower level communication functions. DMX systems almost always need to manually allocate DMX loops and multiple data lines, and it is always difficult to get the best distribution solution. In addition, DMX systems consisting of multiple vendor devices do not have remote error reporting.
[What is the design goal of ACN?]
The following are the minimum design goals for the E1.17 (ACN) project:
(1) Interoperability of products from different manufacturers This agreement should allow products from different manufacturers to communicate effectively with each other. For example, you can use a manufacturer's dimming station to control another manufacturer's silicon box or computer light.
(2) A variety of control and controlled devices are on the same network, ACN protocol should be able to support multiple control data transmission and multiple data receiving devices work together.
(3) Multiple independent control methods This protocol should allow multiple independent control modes to be supported on a single network. For example, for large and complex devices, the subfield with independent addresses can be dynamically configured as a separate control region, and so on. In addition, audio and lighting control can be integrated on one controller. Although this is necessary to see if it is necessary, since the two systems always operate independently, it may be useful to have a method in which two operations can share a single network.
(4) The mainstream protocol ACN protocol should be based on mainstream network protocols. The project does not do duplicate work.
(5) Maximize the use of existing technology This is similar to the aforementioned purpose 4, but more worthy of emphasis. Design this protocol should be able to use a large number of third-party existing network hardware and software (routers, switches, hubs, protocol stacks, diagnostic tools) , etc.) Moreover, the agreement should continue to benefit from the modernization of network technology in the future.
(6) A subset of data and control protocols required to support vendor-specific functions of modern entertainment technology equipment, and is best suited for industry standardization. The protocol applies a first-class approach to support the extension of vendor-specific features. The standardized subset of protocols is not an isolated concept, but naturally conforms to the overall agreement.
(7) The tailorable protocol should adequately address the complex application of large-scale venues. Not only can it be used for minimal use in minimal theaters such as theaters or ballrooms, but it must also be extended to network control to meet large hotels and themes. Complex applications such as parks.
(8) Scalability Design This protocol should be simple and easily scalable to meet the evolving application needs of the future.
(9) Easily configure this protocol to provide a simple configuration and management method for the network. Without manual operation, devices should have the ability to dynamically discover each other. In the field of electronic consumption, this capability is called "plug and play."
(10) Bandwidth efficient use and testable protocols should reasonably save network bandwidth. This goal follows the principles of objectives 2, 3, 7, and 8 above. For example, you should only send as much information as possible that changes in output values, rather than continuously sending all output values ​​to a device like DMX. The available network bandwidth should be testable so that the new system designer can use the network correctly.
(11) Flexible control of subnets and routing In order to achieve tailorability and efficient use of available bandwidth targets, the key is that the protocol cannot limit the choice of standard construction network traffic. That is, network designers must be free to use subnet addressing and The routing method is adapted to the actual network structure used. Subnet addressing provides a way to limit network traffic by isolating complex networks into multiple subnets. Thus, for example, a protocol cannot use subnet addressing to force all devices of a particular type to be installed in the same subnet.
(12) Fault Tolerance The application system using the ACN protocol does not allow frequent network failures, nor can it expect users to have a high level of network expertise to troubleshoot. Ideally, the protocol will cause as few network failures as possible. If a failure does occur, the network will fully return to normal with minimal manual effort.
[What is the current design result of ACN?]
In order to achieve the above objectives, the following results have been achieved for the development of the ACN project:
(1) Get and set the property definition of the completed control device, that is, describe the function of the device as a set of variables or attributes. Device operation is controlled by taking its attribute values ​​to monitor device status and set its attribute values. In the ACN protocol, this is the most basic function implemented by the Device Management Protocol (DMP). The DMP basic information includes the Get Property Value (Get_property) and Set Property Value (Set_property). DMP also defines an addressing scheme for these attributes. (The protocol is called the Property Management Protocol (PMP) in some of ACN's draft documents. What is the correct name, the committee has not yet fully determined).
(2) Identification component.
In a complex network environment, there is no one-to-one communication between network interfaces. The operation of the device to send and receive data requires some mechanism to identify and address the sender or receiver. It also requires a permanent identification of the device, which does not change due to network changes. In the ACN protocol, each endpoint that sends and receives data is called a component, and all communication takes place between components. Each component has a unique identifier, the CID. The component identifier is not only in the system, it should be common throughout the world, and it does not change over time.
(3) Information packets and multipoint transmission.
The Get/Set_property information is usually very short, but using Ethernet and TCP/IP protocol transmissions is most efficient when transferring large amounts of data, while it is inefficient when transferring small packets. To address this imbalance, ACN aggregates a large amount of short messages into a single packet and sends a packet containing multiple messages to all relevant devices at once, unpacking and extracting their own information. Sending a packet to a group of devices is called "multipoint transmission."
(4) Special features of controllable components.
DMP provides a common way to get and set component properties. If you do not recognize the function represented by the attribute, the controller will not operate. This method may be useful for attributes with special features that always have the same address, but this will be difficult to handle and violates the design principles of targets 7 and 8 (ie, tailorability and scalability). In the ACN, device properties and special features are reflected by the description of the respective device. The Device Description Language (DDL) defines the format and language of these descriptions so that the controller can find the functionality of each device property. Not only does the DDL mode make it easy for the controller to find out the properties of known functions, such as brightness or brightness, but it also helps to design smarter controllers that know how to handle functions that have never been controlled before.
(5) Reliability.
If a set property (Set_property) message is lost or the order of arrival is garbled, the device will be in an abnormal state. The DMX512 protocol can ignore this problem because it is assumed at design time that another message will arrive soon, so the abnormal state will only last for a short time. This continuous data transmission not only makes the network bandwidth use efficiency very low, but also cannot solve the problem of setting attribute information loss if the transmission medium is not perfect. A better approach is to use a reliable transmission method to ensure that the order of the information is normal, or if an error occurs, the controller knows what the error is. The easiest way is to let the receiving device feedback that each packet has been received, but it is not feasible in the multipoint transmission protocol, because the sent packets may reach hundreds of devices, if they are received by feedback Packets, then the network may be blocked by the feedback packets. Therefore, there is a need for a reliable multipoint transmission technique. ACN's SDT (Session Data Transport protocol) is a reliable multipoint transmission technology.
(6) Discovering easy configuration (design goal 9) means that the operator does not have to tell the controller what devices are online and how to control them. The controller is able to automatically find the device and configure the device to make control of these devices, called discovery. The ACN discovery is divided into several steps: First, the controller must find which ACN components are on the network; second, the controller must identify the type of component. Third, the controller must find the attribute structure of the device so that it can be controlled when needed. Step 1 uses the Internet standard Service Location Protocol (SLP) to complete the device search, which conforms to the design objective 5 principle (maximize the use of the existing technology), the second step uses the DMP protocol to complete the device identification, and the third step passes the device identification. Detect the description of the special device by the DDL protocol to complete device control.
(7) Layering.
According to design goals 3, 6 and 8, it is advantageous to separate reliable multipoint transmission techniques from the Get/Set device property (Get/Set_property) protocol. This is why SDT, DMP and DDL are separated into three protocols. This separation allows the protocol to be used for other situations (eg, respective protocol functions, field control, time coding, file transfer, and information flow) to obtain the reliability and group management functions provided by the SDT protocol. If the SDT mode does not meet your needs (for example, running the DMX512 protocol on the ACN Series EIA-485 communication protocol), you can use the DMP protocol to resolve it. Last but not least, layering the protocol simplifies the design and implementation of the ACN protocol set, as each layer only covers the parts that are relevant and can be easily defined.
(8) Universal package format.
The information in the SDT and DMP protocols has many similarities. By using a common information format suitable for all ACN protocols, the encoded and decoded information can be shared among different information types. Therefore, ACN defines a common information format: Protocol Data Unit (PDU).
The network protocol can be optimized for packet size, processing speed, or ease of processing code, but all of these optimizations involve balancing issues. Design goal 10 is to make efficient use of bandwidth. The ACN PDU format can package a large amount of optimization information into separate packets to suit the most efficient optimization packets of the network. This will slightly increase the complexity of information processing, but through actual analysis, the information transmission efficiency of the packet is shown. It will increase by more than four times. The high efficiency of data transmission obtained by using the general format of the PDU and the various layer protocols is sufficient to offset the small increase in complexity due to processing information. At the DMP protocol layer, the addressing mechanism and the use of addressing ranges and fast execution of commands will allow a large number of attribute values ​​to be transmitted with minimal system cost. Therefore, the use efficiency of ACN bandwidth is increased.
(9) The transmission of the Internet and most commercial LANs use the TCP/IP protocol suite. There is widespread acceptance of the TCP/IP protocol set that there are a large number of commercially available hardware and software products running on such networks. Moreover, as business needs continue to evolve, it means that TCP/IP as a platform will continue to grow and will be supported by ACN for the foreseeable future. Based on these considerations, a subset of the TCP/IP protocol set will be used as the lower layer protocol of the ACN.
TCP/IP is a protocol implemented using low-level network technology software in the ISO7498 open system interconnection model. TCP/IP provides an abstraction of the network, so applications that communicate over TCP/IP usually don't pay attention or even know what low-level networking technology is. Common technologies currently used to support the TCP/IP protocol include IEEE802.3 (wired Ethernet), IEEE802.11 (wireless Ethernet), IEEE1394 (FireWire), modem and other trunk-distributed connections and high-speed connections such as ATM, SONET. And network structures such as FDDI. With the advent of many new technologies, the TCP/IP protocol will be applicable to these new technologies, and applications using the TCP/IP protocol will also be readily adaptable to these new network technologies.
ACN is not an Ethernet protocol, but a TCP/IP-based protocol. ACN is not obsolete due to the emergence of new network technologies. In contrast, applications using the ACN protocol will benefit from advanced networking technologies.
Although TCP/IP can provide a large number of network functions, it does not provide all the features required by ACN. The UDP (User Datagram Protocol) protocol can provide basic multi-point addressing, but does not provide any reliability or mechanism to manage network traffic in a multicast group. More importantly, the TCP/IP protocol only Used for normal transmission purposes, but does not pay attention to the meaning of the transmitted data, they can be any data from video stream to database query. Moreover, in widely used TCP/IP compatible protocols, there is no applicable application layer protocol to define the information that is controlled. ACN provides this special application layer protocol.
ACN uses only a subset of the TCP/IP protocol set and makes it as small and simple as possible. Instead of using the complex Transmission Control Protocol (TCP), ACN uses a simpler user packet protocol, UDP, to transmit data. Therefore, ACN no longer needs the TCP/IP protocol stack to support data unpacking and packaging.
In order to get a better protocol module design, the interface between ACN and TCP/IP must be clear and easy to define. Where ACN is required to operate on a selectable transport protocol, it is also possible to separate the ACN from TCP/IP, which is also possible. Maintaining this separation status will facilitate the update processing of the respective versions.
[A brief introduction on how ACN works?]
The device on the Ethernet controls the ACN system. First, the SLP protocol discovers that the new device is online, and then the DDL protocol analyzes and sets the respective functions of these devices. The controller sends a Get/Set property message to the device defined by DMP. This information is transmitted via the SDT protocol, which provides functions such as reliability transfer, presence and device group management. All DMP and SDT information is packed into separate PDUs in the normal protocol data unit PDU format. These packets are then transmitted over Ethernet over the UDP protocol (part of the TCP/IP protocol suite). see picture 1 .
[What are the components of the ACN protocol set?]
The following is a detailed description of the components of ACN, including: system components, protocol data units, device management protocols, session data transfer protocols, and device description languages.
(1) Components.
As mentioned earlier, there is no one-to-one relationship between data sources and network interfaces. First, a device typically has multiple network interfaces because it can support multiple network media (such as Ethernet and modem connections) or because the device is connected to multiple network segments. Second, a computer may run two or more independent programs using the ACN protocol. These programs do not have a clear connection to each other, but share the same network interface. An ACN component is a termination point for sending and receiving ACN data. All ACN communication takes place between components.
The ACN component has a unique component identifier (CID) that spans 128-bit values ​​in space and time. That is, the unique component in the network always uses the same identifier regardless of whether the network is the same or the power supply is interrupted. The algorithm for generating the component identification CID is defined in ISO/IEC 11578:1996 and DCE 1.1: Remote Procedure Call. (see http://) Txt.) Using this algorithm, manufacturers can generate CIDs for their products without consulting an authorized organization or registering a unique CID. This means that the computer can also generate its own CID. This ability allows a piece of software (such as downloading from the Internet) to automatically run on many systems without having to manually set a separate identifier, or the system can generate variable temporary components to perform some transient functions.
(2) Protocol Data Units (PDUs).
The ACN packet format ensures that all ACN protocols can construct their own packets in the same way. Each ACN command and information is encoded into a respective protocol data unit PDU that has the same header structure. Each ACN packet consists of one PDU block, one PDU block is a group of PDUs. Some PDU types are defined to contain additional data and another PDU block and can be nested (see Figure 2). PDU nesting Depends on the respective PDU type of each protocol. For example, in the DMP protocol of SDT, there are no PDUs whose nesting depth exceeds that of the second layer.
The PDU structure and header format ensure efficient packaging of commands and data. Adding a new protocol or command simply updates its value in the corresponding field of the header. The standard header allows the receiving device to quickly and easily identify and skip those that are not Special protocols or commands supported.
(3) Device Management Protocol (DMP).
DMP is a protocol used by ACN as a control and setup component on the network. When a component needs to be controlled or needs to provide status information, it uses a set of attribute values ​​to describe its state. The attribute value can reflect any gain from the amplifier to the network parameters (eg Information such as session IDs. By getting or setting properties, a component can query or control another component. Because these properties have a variety of data types, almost any control function can use set properties (Set_property) or get properties (Get_property Values ​​are described. These get and set attribute values ​​can be manipulated individually or within a certain range to allow for the most efficient operational performance and network bandwidth.
The DMP protocol requires a low-level session transport protocol to ensure that all components can receive DMP information sent to them (unless it is unreliable data), and the information is received in the same order as sent. In the TCP/IP protocol network (including Ethernet), DMP uses the SDT protocol.
(4) Session Data Transfer Protocol SDT (Session Data Tansport).
SDT is a transport protocol used by ACN on top of the UDP protocol in TCP/IP networks to provide the required reliability by establishing a data transfer session. In the SDT protocol, a session consists of a pair of communication channels, called upstream and downstream: the session header has only two components, the component that sends information downstream of the session, and the listening component that sends the response information in the upstream. A stream is usually a multicast group that allows a message to be sent to multiple related listening components. It also allows non-session components to filter information in hardware (UDP multicast addresses are converted to Ethernet group addresses, most Ethernet) The controller can filter the information in the hardware.) Sending the response message on the upstream is usually a single-point transmission direct response to the sending component, because other components will not pay attention to this response message.
The header of the session controls the transmission of packets, the order of packets, the tunable properties of session members and other special network or session purposes. This means that the header needs quite complex performance to support the same complex session purpose. All other in the session Components, both to listen to the commands sent to them and provide responses to the session header, and occasionally send a packet loss message to the session header. ACN also has a provision for the simple transport mechanism, called "continuous ACN". Design continuous ACN Mainly used for low bandwidth lines with limited bandwidth and DMX512 protocol transmission or other controller transmission. At this time, using SDT will increase the unnecessary burden, and may send DMP through a suitable connection and physical layer. In these cases, There is only one session on a continuous link, and the session is guided by a link controller (ie, a dimming station).
(5) Device Description Language (DDL).
DDL is a standard language that describes what special components are included in a device. It also establishes device definitions to describe the properties and functions of the device. DDL uses a subset of eXtensible Markup Language, a standard language for describing files and defining file templates. DDL is expected to be a simple language that everyone can understand, so that computer definitions can be automatically loaded and processed by a computer. DDL provides a device model that constructs a relationship between the required attributes and the applicable controls. Device attribute information. A DDL device can describe all or part of a component's properties in order to describe a single DMP component as a separate device using DDL. Any device type can be identified by the device type identifier DCID (Device Class ID) and can be read from the component. Devices with the same DCID are guaranteed to have the same set of attributes and functions, and are guaranteed to be unique to the same type of device. Identification. Therefore, any component that knows how a particular type of device interacts can quickly identify such a device. If the DCID of the device is not known, the ACN can send a DDL description on the network, allowing the relevant component to learn How to interact with these devices.
Conclusion
In recent years, with the vigorous development of the national economy, domestic large-scale stage and TV studio projects have sprung up, and the network lighting control system has become a hot topic for lighting engineers, owners and related parties. A large number of project recruitment, bidding, construction, supervision and acceptance work requires the support of the standard of the lighting network. Whether the Chinese need to immediately develop a standard agreement for their own lighting network.
The author is fortunate to represent the domestic lighting company HDL (ESTA International Member of 2003) in close contact with the ESTA organization and standards office, and participate in the planning and invitation of experts from the ESTA Standards Office to exchange lectures and other activities in China. The author believes that: I have the responsibility and obligation to continue to work with experts in the domestic lighting industry to understand and in-depth study of ACN advanced network control protocols, and to make their own contribution to the standardization of network equipment in China's lighting industry!
LUPHITOUCH dedicated to lean manufacturing techniques in all of our operations, including human interface assemblies manufacturing, PCBA, Integrated Assemblies and turnkey assemblies. We have numerous integrated assemblies working experiences dedicated to our customers` semi-finished products and completed products, ensuring that we continually maximize efficiency and improve our processes through skillful workers and strong engineering capabilities.
We established completed green supply chain which ensure us can get the qualified materials and components of the plastic, Hardwares, cable, LCD, touchscreen and other electronics components very quickly.
Integrated Assemblies
Integrated Assemblies,Wrapping Integrated Assemblies,PCBA Integrated Assembly,Electronics Components Integrated Assemblies
Dongguan LuPhi Electronics Technology Co., Ltd. , http://www.luphiprint.com