Transmission of information over power networks using IS from Semtech (2015). Technologies and components for data transmission over power lines
Power Line Communication (PLC) technologies are actively developing and becoming more and more popular all over the world. And Russia is no exception. They are used in the automation of technological processes, the organization of video surveillance systems, and even to control a "smart" home.
Research in the field of data transmission using the power grid has been going on for a long time. In the past, the use of PLCs was hindered by low data transfer rates and insufficient immunity to interference. The development of microelectronics and the creation of modern, and most importantly more efficient processors (chipsets), made it possible to use complex modulation methods for signal processing, which made it possible to make significant progress in the implementation of the PLC. However, only a few experts are still aware of the real possibilities of communication technology over the power grid.
PLC technology uses electrical networks for high-speed data transmission and is based on the same principles as ADSL, which is used for data transmission in the telephone network. The principle of operation is as follows: a high-frequency signal (from 1 to 30 MHz) is superimposed on a conventional electrical signal (50 Hz) using various modulations, and the signal itself is transmitted through electrical wires. The equipment can receive and process such a signal at a considerable distance - up to 200 m. Data transfer can be carried out both over broadband (BPL) and narrowband (NPL) power lines. Only in the first case, data transfer will go at speeds up to 1000 Mbps, and in the second it will be much slower - only up to 1 Mbps.
At the speed limit?
Today, third-generation PLC technologies are available to users. If in 2005, with the advent of the HomePlug AV standard, the data transfer rate increased from 14 to 200 Mbps (this is enough to provide the so-called "Triple Play" services, when users are simultaneously provided with high-speed Internet access, cable TV and telephone communication) , then the latest generation of PLCs already uses a dual physical data transfer layer - Dual Physical Layer. Together with FFT OFDM, Wavelet OFDM modulation is used, that is, orthogonal frequency-separated multiplexing, but using wavelets. This allows you to increase the data transfer rate several times - up to 1000 Mbps.
However, it is important to understand that we are talking about physical speed. The actual data transfer rate depends on many factors and can be many times less. The quality of electrical wiring in the house, twisting in the line, its heterogeneity (for example, in aluminum wiring, the signal attenuation is stronger than in copper, which reduces the communication range by about half) - all this has a destructive effect on the physical speed and quality of data transfer. Also PLC - all adapters must be on the same phase in the electrical network, there should not be galvanic isolation between the adapters (transformers, UPS), pilots, filters and RCDs reduce the data transfer rate. The exception is QPLA-200 v.2 and QPLA-200 v.2P, because A feature of these adapters is the unique Clear Path technology. Using Clear Path technology, it is possible to create a network even when PLC devices are connected to different phases, i.e. this technology dynamically selects less noisy channels for transmitting information, thereby increasing the data transfer rate. Up to 8 devices can be in one PLC network.
Speaking of PLC technology, it is customary to take half-duplex or unidirectional speed as the speed. That is, if the indicated speed is 200 Mbps, then the real one will be 70-80 Mbps. In real life, physical speed can be halved with great confidence, and proportionally reduced by 10% when connecting each powerful home device - iron, kettle, air conditioner, refrigerator, etc.
Under normal household conditions, a signal can be transmitted over wires using a PLC over a distance of about 200 m. For example, a house with an area of 200 square meters. m can be covered without problems. The quality of communication in this case will depend on the quality of the electrical network. An ordinary surge protector, which is often built into an extension cord, uninterruptible power supply or transformer, can become an obstacle to the passage of the signal. It should also be remembered that the distribution of the network through the wiring is limited to an electrical panel with fuses. So creating a network, for example, with a flatmate will not work. Wi-Fi is better for this.
PLC pros and cons
PLC technologies certainly deserve attention, but along with the advantages, they also have obvious disadvantages. But first things first. PLC helps to establish high-quality provision of Triple Play services, does not require laying wires for data transmission, and, therefore, additional costs. Fast installation and the ability to connect to existing networks is also a point in favor of the PLC. In addition, the PLC network can be easily dismantled and configured, for example, when the office moves to another building. Such a network is easily scalable - you can organize almost any of its topologies at minimal cost (depending on the number of additional PLC adapters). In difficult conditions (reinforced concrete structures, high level of electromagnetic interference), unlike Wi-Fi, WiMAX and LTE wireless technologies, the PLC network will work without failures. At the same time, due to the use of the most modern encryption algorithms, secure data transmission over the network is also ensured.
PLC has fewer disadvantages, but it's worth knowing about them. Firstly, the bandwidth of the network through electrical wiring is divided among all its participants. For example, if two pairs of adapters actively exchange information in one PLC network, then the exchange rate for each pair will be approximately 50% of the total bandwidth. Secondly, the stability and speed of the PLC is affected by the quality of the electrical wiring (for example, copper and aluminum conductors). And thirdly, the PLC does not work through surge protectors and uninterruptible power supplies that are not equipped with special PLC Ready sockets.
Application of PLC in practice
Today PLC finds wide practical application. Due to the fact that the technology uses the existing power grid, it can be used in process automation to link automation units via electrical wires (for example, city electricity meters).
Often, PLCs are used to create video surveillance systems or a local area network in small offices (SOHO), where the main requirements for a network are ease of implementation, device mobility, and easy scalability. At the same time, both the entire office network and its individual segments can be built using PLC adapters. It is often necessary to include a remote computer or a network printer located in another room or even at the other end of the building in an already existing office network - using PLC adapters, this problem can be solved in a few minutes.
In addition, PLC technology opens up new opportunities for implementing the idea of a "smart" home, in which all consumer electronics should be tied into a single information network with the possibility of centralized control.
With the current level of development of computer technology and network technologies, strict requirements are imposed on networks. The computer network must provide the transmission speed required for specific conditions; it should also be mobile, with a large number of access points, and it should not require cable laying; the network should have simple administration; it should provide high reliability with simple technical solutions; the network must support all possible types of network equipment and at the same time it must be cheap.
With the general global computerization of both the ordinary population and enterprises, organizations and special services, it became necessary to organize computer networks
One of the options for organizing networks is a system for transmitting data over power grids.
The thesis will show a scheme for organizing a data transmission network over power networks using the example of Alkhan-Churt settlement using PLC technology
The BZD section is carried out in order to create safe working conditions when working with power supply networks
In the economic part of the diploma, the cost of the network being designed and the economic feasibility of building a network based on PLC technology will be calculated
PLC technology is, first of all, a solution to the "last mile" problem. Because this solution uses an in-house electrical network. The service itself is provided on a Plug&Play basis. That is, an adapter or subscriber modem purchased by a consumer in a store does not require any settings: when plugged into a power outlet, it automatically communicates with the head unit, which is the only one in every home; the configuration is automatically configured and the IP address is assigned. The advantage of the technology is also the fact that to connect to the Internet there is no need to wait for fitters and let them into your home. Another additional plus is roaming: the modem works in all houses where there is PLC coverage. It is not strictly registered to a specific address and works both within the district, and within the city, and in another city too. Now networks are being built simultaneously in five cities, and at least 5-6 more cities of Russia are at the stage of preparation of projects.
With all the advantages of this technology, the Internet access market is already saturated, and we literally feel first hand how slowly the subscriber base is growing. If the client has already connected to the provider and made the wiring, then it makes no sense to attract him with a low price, especially since by lowering prices the operator puts himself in a difficult position. The average payment for broadband access is already low. Therefore, for development, it is necessary to introduce new services and services. For example, the so-called "constructor". Different modules are "attached" to the basic PLC modem: Ethernet socket; Wi-Fi hotspot; a telephone module to which you can connect a regular analog landline phone, an internal set, and a VoIP device. With the help of the latter, it is possible to organize an internal telephone network within the city (for example, direct telephone communication channels with relatives).
Another plug-in is a video camera, with which you can organize a video surveillance system at home without even connecting it to a computer. It transmits all traffic over the power grid to the provider's server. And a user anywhere in the world can go online, go to his personal account on the client interface and check the situation at home. This solution is ideal for monitoring children, babysitters and housekeepers. In addition, various additional functions can be configured through the Web interface, such as, for example, a motion detection system (motion control), which will allow the camera to perform the functions of a three-dimensional motion sensor: when the picture has changed, a signal is sent to the server, an SMS is sent to the user's mobile phone - it connects to the Internet and checks if everything is in order.
PLC (Power Line Communications) technology, also called PLT (Power Line Telecoms), is a wired technology that uses the cable infrastructure of power networks to provide high-speed data and voice transmission. Depending on the transmission rate, it is divided into broadband (BPL) with a speed of more than 1 Mbps and narrowband (NPL).
Testing of a broadband internet service over the electricity grid has been launched in Scotland. This initiative belongs to the electric power company Scottish Hydro Electrics. According to the British edition of PC Advisor, about 150 users were involved in testing "Internet through a socket". Each subscriber received Internet access at a speed of 2 Mbps. For the price, it was more than twice as good as the other ISP's offer. Several energy companies in the country have already shown interest in the new service. In addition, the leading electricity supplier in Germany, RWE, is dynamically implementing PLC. For example, in Germany, people don't even fill out electricity bills: information from the meters comes directly to the electricity supplier via electrical wiring. Similar projects have been launched in Italy and Sweden.
In Russia, the first stage of building a network based on PLC technology was carried out by the Spark company and completed in October 2005. At that time, the network included more than 750 access nodes located in residential buildings. All access nodes are connected by a Gigabit Ethernet backbone optical network. In 2006, a pilot project was launched to put PLC technology into operation in the Yuzhnoye Tushino area, and in 2007, active construction of the network and connection of subscribers began.
Low Internet access fees ensure good competitiveness, but the quality is sometimes criticized by potential and current subscribers (judging by the numerous discussions on the forums). For example, users complain about the problem of being able to connect to the Network only through a certain outlet in the apartment, which is not always convenient for the subscriber, as well as a decrease in speed when turning on electrical appliances. This is due to the general condition of the electrical wiring of the apartment, but such problems are solved by the provider's specialists. In addition, to avoid any problems, it is recommended that the user device be connected to a separate outlet. Nevertheless, telecommunications industry experts hold a low assessment of the potential for the development of PLC networks. The reason for this is the technology itself. To transfer data from computer to computer, Ethernet technology was specially developed, as a result, when using it, the cost of terminal equipment is the lowest, and the speed characteristics are the best. Any attempts to adapt a medium that was not originally intended for data transmission lead to a higher cost of equipment and to worse technical characteristics. This applies to telephone copper wire (dial-up modems or ADSL) and power networks (PLC technology).
The so-called "last mile problem" that has been talked about so much lately has given rise to many solutions. However, most of these solutions have one common drawback - they all require the laying of wires and cables. Probably, it makes no sense to talk about what difficulties and difficulties this sometimes causes - very often the cost of laying a cable makes up a large part of the cost of setting up a network. Moreover, there are a number of cases in which laying new cables is impossible or highly undesirable - a vivid example of such an unpleasant situation is a recently completed repair, immediately after which it suddenly turns out that it is necessary to lay additional wires for computer networks.
Therefore, technologies that made it possible to do without laying new cables have always been of particular interest. At the moment, there are two successful approaches to this problem - these are wireless Wi-Fi networks and PLC technologies. If a lot has been written about wireless networks, then much less information is available about PLC technologies.
PLC technologies make it possible to build computer local networks based on existing power lines. So, using PLC technology, you can build a small home local area network using the electrical wiring that has already been laid.
In fact, methods of transmitting information using electrical wiring have existed for a long time. One of them is the well-known Soviet loudspeakers (which are also often incorrectly called radio stations). The various technologies are based on a fairly simple idea of signal separation - if in some way it would be possible to simultaneously transmit several signals over one physical channel, then in this way it would be possible to increase the overall data transfer rate. This can be achieved using modulation (besides, the modulated signal is resistant to interference), and with different modulation methods on the same physical data transmission channels, different data rates can be achieved.
At first glance, the recipe for successful PLC technology may seem simple - just choose a modulation method that could provide the fastest data transfer, and a modern communication facility is ready. However, those modulation methods that provide the most dense signal packing require complex mathematical operations, and in order to be used in PLC technologies, the use of fast signal processors (DSP) is necessary.
A digital signal processor (DSP) is a specialized, programmable microprocessor designed to manipulate a stream of digital data in real time. DSP processors are widely used to process graphics, audio and video streams.
Thus, the development of PLC technologies rested on the pace of development of DSP processors, and as soon as the latter began to cope with advanced efficient modulation algorithms, new technologies for organizing such networks appeared. At the moment, PLC technologies use OFDM modulation, which makes it possible to achieve high data transfer rates and good signal immunity to interference.
Broadband Internet access;
Home and office computer networks;
VoIP - IP-telephony;
High-speed audio and video transmission;
Office and home (including via the Internet) video surveillance, building remote video monitoring systems;
Construction of digital data transmission channels for industrial and home automation (AIIS KUE, ACS TP (SCADA), ACS);
Security systems (fire and burglar alarms).
The success of the business of telecommunications operators, as well as the effective functioning of departmental and corporate communication networks, largely depends on the solutions used for building access networks.
Fiber-optic communication lines provide data transmission at high speed, but they do not yet reach the mass user, being widely used, as a rule, in the corporate sector.
In the mass market of subscriber access today, xDSL technology is considered the most in demand, which provides users with access to the Internet and other infocommunication services via existing telephone lines. A certain share in this segment is also occupied by such technologies as broadband wireless radio access and satellite access, access via cable television networks, packet data transmission in cellular networks 2.5G / 3G (GPRS / EDGE / UMTS, CDMA 2000 1X / EV-DO).
Factors such as the widespread use of 0.2-0.4 kV electrical networks, the absence of the need for expensive construction of cable ducts, punching walls and laying communication cables, etc. stimulate the study of power networks as an alternative data transmission medium and the development of another broadband access technology - by electrical networks.
First and second generation PLC equipment was developed. The achieved maximum data transfer rate did not exceed 10-14 Mb/s. The actual data transfer rate in PLC test networks using this equipment differed by an order of magnitude and amounted to 1-2 Mb/s. In addition, PLC subscriber equipment had a relatively high cost, and power lines "compacted" by PLC were characterized by a high level of electromagnetic radiation due to the operation of PLC equipment.
Therefore, until recently, PLC technology was used for the commercial provision of telecommunications services on a limited scale, being uncompetitive in relation to other technologies, and primarily xDSL. However, recent advances in microelectronics, which have made it possible to create third-generation PLC systems that provide data transfer rates up to 200 Mb / s using standard power lines, open up new opportunities for implementing broadband access.
Modern PLC systems focused on solving the problem of broadband subscriber access mainly use two technologies. The first uses a signal with the so-called. spread spectrum (SS), which significantly increases the noise immunity of the transmission. When using SS modulation, the signal power is distributed over a wide frequency band, and the signal becomes invisible against the background of interference. On the receiving side, meaningful information is extracted from the noise-like signal using a pseudo-random code sequence unique for this signal. With the help of different codes, it is possible to transmit several messages at once in one wide frequency band. The described principle underlies the code division multiple access (CDMA) method. Note that in addition to noise immunity, SS-modulation provides a high level of information protection. QPSK modulation is used as the base.
The second technology is based on orthogonal frequency division multiplexing with simultaneous transmission of signals on several carriers (OFDM - Orthogonal Frequency Division Multiplex). This method also guarantees high transmission fidelity and resistance to signal distortion.
A further development of the second option was the technology proposed by the American company Intellon. Here, a modified OFDM method is used, in which the original data stream is divided into packets, and each of them is transmitted in the frequency range of 4.3-20.9 MHz using relative phase modulation on its own subcarrier (DBPSK or DQPSK - Differential Quadrature Phase Shift Keying , shifted differential quadrature phase modulation). The maximum information transfer rate reaches tens of Mbps.
The PLC technology implements the principle of multiple access “point - many points”. A local transformer substation supplies a certain number of buildings with electricity and, at the same time, provides connected users with data transmission services, IP telephony, etc.
The main terminal equipment should be considered a PLC modem, which usually implements an interface for communication with a PC: USB or Ethernet. Thus, the modem is connected to a source of information - a 220V socket, and at the output via the appropriate interface to a PC. It is possible that a phone that supports VoIP mode is connected in parallel with the PC.
A typical functional diagram and the main components of the PLC modem are shown in fig. 1.1.
Rice. 1.1. PLC modem components
The connection to the Internet in this innovative technology is called Broadband over power lines (BPL).
Unlike a DSL connection, through a home network, the technology allows more people to have broadband Internet access.
PLC technology is the cheapest way to create a home network, as it does not require the user to install additional power cables and allows you to connect residents of an entire block to the PLC network. One master device is able to provide Internet access through the PLC network for 500 users. To do this, users must have adapter devices containing PLC modems in their apartments.
Of course, the most successful projects for the organization of broadband access via power grids have been implemented in the United States - the birthplace of the Internet. Known companies such as New Visions (New York), Communications Technologies (Virginia), Cinergy (Ohio).
In Germany PLCs are offered by Vype; Piper-Net and PowerKom; in Austria - Speed-Web; in Sweden - ENkom; in the Netherlands - Digistroom; in Scotland - Broadband.
In 2005, the deployment of Internet access networks through household electrical networks using PLC technology began in the Russian Federation.
Internet access is evolving, and soon even in your country house, where there are no telephone and cable lines, you will be able to connect to the Internet.
In most cases, PLC systems are classified according to the voltage of the power network on which they are used and the coverage area (territory):
used on high voltage lines (HV);
used on medium voltage lines (MV);
applied on low voltage lines (LV):
last mile;
inside the building;
indoors (apartment).
The PLC includes B, which provides data transfer rates greater than 1 Mbit per second, and NPL, with much lower data rates.
When transmitting signals over a household power supply, there may be large attenuation in the transmitting function at certain frequencies, which can lead to data loss. PowerLine technology provides a special method for solving this problem - dynamically turning off and on data-carrying signals. The essence of this method lies in the fact that the device constantly monitors the transmission channel in order to identify a portion of the spectrum with a certain attenuation threshold exceeded. If this fact is detected, the use of these frequencies is temporarily stopped until the normal attenuation value is restored.
There is also the problem of impulse noise (up to 1 microsecond) from halogen lamps, as well as turning on and off powerful household appliances equipped with electric motors.
No matter how optimistic the results of the work of experimental PLC networks abroad may be, in our country this technology runs the risk of encountering a number of difficulties. Domestic electrical wiring is made mainly of aluminum, and not of copper, which has found application in most countries of the world. Aluminum wires have poorer electrical conductivity, resulting in faster signal attenuation. Another problem is that we still have not resolved the main issues of legal regulation of the use of such technologies. However, the latter is also true for the West. The main factor hindering the rapid development of high-speed PLC systems is the lack of standards for wideband PLC systems and, as a result, a high risk of incompatibility with other services using the same or similar frequency bands. In 2001, the HomePlug Powerline Alliance, an international consortium, adopted the industry standard for building home networks over household wiring lines, the HomePlug 1.0 specification. But this standard regulates the construction of "home" networks, that is, networks within the same apartment (cottage). A full-fledged standard for broadband PLCs has not yet been developed.
The main organizations and communities involved in the standardization of various aspects of this technology are IEEE, ETSI, CENELEC, OPERA, UPA and the HomePlug Powerline Alliance.
IEEE announced the creation of a group that will develop the BPL standard. The project is named IEEE P1675, "Standard for Broadband over Power Line Hardware".
In addition to IEEE P1675, there are three more directions:
IEEE P1775, initiated to regulate PLC equipment, EMC requirements, test and measurement methods;
IEEE P1901, "Standard for Broadband over Power Line Networks: Medium Access Control and Physical Layer Specifications", which provides a description of the physical and media access layers for all classes of BPL devices;
IEEE BPL Study Group, "Standardization of Broadband Over Power Line Technologies", providing for the creation of new groups related to BPL.
The European Telecommunications Standards Institute has formed the ETSI Technical Committee Power-Line Telecommunications (TC PLT), which is responsible for PLC standardization.
CENELEC is a non-profit organization made up of the National Electrotechnical Committees of the EU Member States and is the most significant organization in the EU in the field of electromagnetic field standardization. For PLCs, CENELEC performs the creation of PLC specifications for the physical layer and media access sublayer; adopted the corresponding standard EN55022 .
The Open PLC European Research Alliance (OPERA) consortium was established in 2004 as part of the Broadband for All European program to promote high-speed Internet access technologies. OPERA's work consists of two phases, each of which takes two years to complete.
The main initiator and source of funding is the European Commission. The total budget is more than 20 million euros, a significant part of the funds is allocated under the FP6 program. The completion of the OPERA project is expected in 2008. In total, more than 30 companies and research institutes from 12 countries are participating in the project.
OPERA's specifications to date cover PHY, MAC, and data communications equipment over power networks.
The UPA was officially announced in December 2004. The main declared goal of UPA is to promote PLC technologies and demonstrate to governments and industry leaders the prospects for its large-scale use. UPA is developing standards and regulations to ensure the rapid development of the PLC market. Provides market participants with information about open standards based on interoperability and security.
For the wide introduction and development of HomePlug technology (one of the first transmission technologies over power lines), standardization and compatibility of devices from different manufacturers using this technology, the international industrial alliance HomePlug Powerline was organized in 2000. Today, more than 80 firms are sponsors, members of the alliance, and adhere to its recommendations. Among them are such well-known companies as: Motorola, France Telecom, Philips, Samsung, Sony, Matsushita, Sanyo, Sharp, Panasonic and many others. The HomePlug Certified Alliance Mark on any manufacturer's product indicates that the device complies with all requirements of the HomePlug Powerline standard and is fully compatible with similar devices from another manufacturer.
The first HomePlug Powerline Specification 1.0 is based on the Power Package™ technology proposed by Intellon (USA) and adopted as a standard by members of the HomePlug Powerline Alliance. The standards adopted so far and under preparation are presented in Table. 1.1.
Table 1.1. HomePlug Powerline Alliance Core Standards
| Name | Acceptance date | Note |
| HomePlug 1.0 | June 2001 | Defines technology to provide data transfer rates up to 14 Mbps |
| HomePlug 1.0 Turbo | It is an evolution of the 1.0 specification with a maximum data transfer rate of up to 85 Mbps | |
| HomePlug AV | Defines PLC technology with transfer rates up to 200 Mbps. The specification provides for the provision of the quality of service required for the transmission of audio and video streams. Encryption - 128-bit AES | |
| HomePlug Command and Control | September |
Defines control and management of HomePlug devices |
| HomePlug BPL | Under development |
Today, developments in the field of PLC are carried out by several hundred companies engaged in both the production of chipsets and the creation of finished devices based on them. Here are just a few of the industry players: ABB, Adaptive Networks, Alcatel, Ambient Corporation, Amperion, Ascol, Cisco Systems, Cogency, Corinex, Current Technologies, DataSoft, DefiDev, DS2 (Design of Systems on Silicon), Echelon, Eicon, Electricom, Enikia, Ericsson Austria AG, HP, llevo, Intellon, Krone AG, Linksys, Lucent Technologies, Metricom Corporation, Mitsubishi, Netgear, Northern Telecom, Nor.Web, Philips, PowerNet, PowerWAN, Schlumberger, Schneider Electric, Sumitomo Electric Industries, Telkonet .
The undisputed leader in the production of ICs (chips) for third-generation PLC systems is Design of Systems on Silicon Corporation - DS2 (Spain). It was founded in 1998 and produces a functionally complete set of products that allows you to implement a complete solution for the problem of broadband access based on PLC. One of the first DS2 introduced at the end of 2003 a number of third-generation ICs, providing exchange rates up to 200 Mb / s. While DS2 products do not support the HP v.AV standard.
Main ICs DS2:
DSS9001: based on this IC, PLC modems and In-Door class equipment can be implemented;
DSS9002: Emitters and Repeaters can be implemented on the basis of this IC;
DSS9003: Dedicated IC for interfacing the power grid and FOCL;
DSS9010: Dedicated IC for High Speed Solutions
The implementation of a PLC system based on DS2 products is shown in fig. 1.2.
Rice. 1.2. Implementation of a PLC system based on DS2 products.
Another leader is Intellon Corporation (USA), which was one of the co-founders of the HomePlug alliance. For the HomePlug v.1.0 specification, Intellon has prepared the following ICs: INT51X1, INT5200, INT5500CS. In September 2002, the company introduced the world's first certified HomePlug 1.0 module - the RD51X1-AP device for organizing an Internet access point using PLC technology. In November 2005, the company announced the release of the 3 millionth product for PLC networks.
For broadband access (HomePlug v.AV specification), Intellon has prepared a set of ICs INT6000. In August 2005, it was announced that the investment arm of Motorola Ventures began investing in Intellon's work to develop the INT6000 chip set. First deliveries are expected in Q2 2006.
Intellon's designs implement PowerPacket technology, which uses an efficient spectrum modulation technique that allows data to be transmitted over power lines at very high speeds. The data transfer rate can reach 100Mb/s. The PowerPacket is a system with characteristics that enable it to adapt to environments with strong multipath, strong narrowband interference, impulsive noise without equalization.
SPiDCOM Technologies (France, www.spidcom.com) is one of the leading developers of the element base for PLC/BPL solutions (BPL is broadband powerline, an abbreviation used in the USA to designate PLC). The latest development of the company - IC type SPC200 provides a transfer rate of about 220 Mb / s. Its serial launch began in March 2005. The HomePlug v.AV compliant variant of the SPC200 will go on sale in Q2. 2006 IC SPC200 uses a range of 2 - 30 MHz, divided into 7 operating bands.
The Israeli company Yitran Communications Ltd is actively cooperating with the HomePlug Powerline alliance. As a result of research, in March 2006 the Yitran solution was selected as the underlying technology in the preparation of the HomePlug v.AV standard (section "Commands and Control").
The company has prepared two third-generation ICs: ITM1 and ITC1. They allow you to realize a peak speed of up to 200 Mb / s. A block diagram of a communication device based on the ITM1/ITC1 IC is shown in fig. 1.3.
Rice. 1.3. Structural diagram of a communication device based on IC ITM1|ITC1.
Yitran Communications has developed and patented Differential Code Key Shift Keying (DCSK) technology to create low-cost, high-performance network components. Details of DCSK are not known; it is only reported that it is based on the methods of adaptive SS-modulation independent of the physical transmission medium in the frequency band 4-20 MHz with turbo compensation and code compression.
Hardware components (transceivers) based on DCSK provide significantly higher transmission speed, noise immunity and information protection than existing CEBus transceivers, at a significantly lower cost of devices. Several products have been announced, including ITM1 (data transfer rate up to 2.5 Mbps) and ITM10 (data transfer rate up to 12 Mbps).
XELine (South Korea) develops both ICs and equipment for PLC solutions. The company offers third-generation IC type XPLC40A, which provides access speed up to 200 Mb/s.
Another Xeline product, the XPLC21 IC, provides access speeds up to 24 Mb/s. Based on it, the Emitter, repeater and directly PLC modem can be implemented. This IC is based on the ARM9 processor. The frequency range used is 2-23 MHz. Structural diagram XPLC21 is shown in fig. 1.4.
Fig.1.4. Structural diagram of IC type XPLC21
The rest of the suppliers are still in the stage of testing third-generation PLC-ICs, continuing to release equipment of the second generation and generation 2.5, the so-called. HomePlug v.1.turbo standard (speed up to 85 Mb/s).
Based on the IC sets discussed above, vendors produce PLC equipment for both the In-Door segment and the integrated solutions segment (for last-mile access).
Below we will indicate the manufacturers of third-generation In-Door class equipment.
The German company devolo AG produces a line of dLAN PLC products that belong to the In-Door class and allow you to create an indoor local area network based on PLC technology.
In March 2006, devolo AG announced that it has prepared for release a new product line dLAN 200, which provides information transfer rates up to 200 Mb / s (HomePlug v.AV) and is implemented on the basis of the Intellon IC.
One of the leaders in the LAN equipment segment, NETGEAR (USA) showed interest in the PLC adapter segment - in February 2006, NETGEAR entered into an agreement with DS2 to start joint work and supply third-generation ICs that will allow mastering the production of PLC devices supporting speeds up to 200 Mb/s. The start of deliveries of new products is scheduled for the third quarter of 2006.
In March 2006, ELCON (Germany) announced the release of the ELCONnect P-200 model, which is implemented on the basis of the DS2 IC, supports the Ethernet interface and provides an exchange rate of up to 200 Mb / s.
Table 1.2. D52 Chipset Specifications
| Constructive | DSS9011 | DSS9010 | DSS9001 | DSS9002 | DSS9003 | DSS7700 |
| PBGA196 | PBGA196 | PBGA196 | PBGA256 | PBGA304 | QFN84 | |
| Interfaces | ||||||
| GIMMI | 2 | |||||
| MII | 1 | 1 | 2 | |||
| TDM | 1 | 1 | ||||
| SPI | 1 | 1 | 1 | 1 | 1 | 1 |
| UART | 1 | 1 | 1 | 1 | 1 | |
| GPIO pins | 9 | 9 | 9 | 9 | 9 | |
| Networking | ||||||
| MAC addresses | Not | 32 | 64 | 1024 | 256k | Not |
| QoS and Broadcast | There is | There is | There is | There is | There is | Not |
| CoS | Not | Not | There is | There is | There is | Not |
| VLAN | 1 | 32 | 32 | 32 | ||
| Functional purpose of devices | ||||||
| CPE | + | + | + | + | ||
| Repeater | + | + | + | |||
| Head unit (head end) | + | + | + | |||
Table 1.3. Positioning of DS2 products
| Name | Purpose | Note | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| DSS9010 | High speed home multimedia applications | QoS management. 802.1d bridging functionality with up to 32 MAC addresses | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| DSS9011 | Budget solution for audio transmission | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| DSS9001 | Advanced home applications and entry-level PLC infrastructure | Support for up to 64 MAC addresses. Oriented for use as part of client terminal equipment (CPE). Has an integrated VoIP port | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| DSS9002 | Access infrastructure equipment | Support for up to 1024 MAC addresses. It can be used in: 1) modems and repeaters of low-voltage networks; 2) gateways between medium-voltage and low-voltage networks; 3) gateways of individual apartments or buildings | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| DSS90D3 | Advanced Access Infrastructure Equipment and Optical Gateways for Metro (Metro) Networks | Support up to 262144 MAC addresses. Provides fast reconfiguration using an optimized Spanning Tree protocol | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| DSS7700 | Analog unit for head unit  , [A/m]
ENEPD - maximum permissible energy load of the component of the electric field strength during the slave. day [(W/m)2×h] ENNPD - maximum permissible energy load of the component of the magnetic field strength during the slave. days [(A/m)2×h] The normalized parameter of the electromagnetic field in the frequency range of 300 MHz -300 GHz is the maximum permissible value of the energy flux density.
PPEPD - limiting value of energy flux density [W/m2],[µW/cm2] K - coefficient of attenuation of biological effects ENPPEPPD - maximum permissible value en. load [W/m2×h] T - action time [h] Previous the value of PPEpd is not more than 10 W/m2; 1000 µW/cm2 in the production room. In residential buildings with round-the-clock irradiation in accordance with SN Þ PPEpd no more than 5 μW/cm2. Reducing the components of the strength of the electric and magnetic fields in the induction zone, in the radiation zone - a decrease in the energy flux density, if this technological process or equipment allows. Protection by time (limitation of the time spent in the zone of the source of the electromagnetic field). Distance protection (60 - 80 mm from screen). Screening method for a workplace or an electromagnetic field radiation source. Rational layout of the workplace in relation to the true radiation of the electromagnetic field. The use of warning devices. Use of personal protective equipment. A person cannot remotely determine whether the installation is energized or not. The current that flows through the human body affects the body not only at the points of contact and along the current flow path, but also on such systems as the circulatory, respiratory and cardiovascular systems. The possibility of electrical injury occurs not only when touched, but also through step voltage and through an electric arc. Email current passing through the human body has a thermal effect, which leads to edema (from redness to charring), electrolytic (chemical), mechanical, which can lead to rupture of tissues and muscles; therefore, all electrical injuries are divided into local and general (electric shocks). Local electric shocks: electrical burns (under the influence of electric current); electric signs (spots of pale yellow color); metallization of the skin surface (getting molten metal particles of an electric arc on the skin); electrophthalmia (burn of the mucous membrane of the eyes). Grade 1: no loss of consciousness 2nd degree: with loss Grade 3: without damage to the work of the heart Grade 4: with damage to the work of the heart and respiratory organs An extreme case is a state of clinical death (stopping the heart and disrupting the supply of oxygen to brain cells). In a state of clinical death are up to 6-8 minutes. Ι. Touching live parts under voltage ΙΙ. Touching disconnected parts where voltage may be present: in case of residual charge in the event of an erroneous switching on of the electrical installation or uncoordinated actions of the operating personnel in the event of a lightning discharge into an electrical installation or near contact with metal non-current-carrying parts or associated electrical equipment (housings, casings, fences) after voltage transfer to them from live parts (an emergency - a breakdown on the housing) ΙΙΙ. Damage by step voltage or stay of a person in the field of spreading electric current, in the event of a ground fault ΙV. Defeat through an electric arc at a voltage of an electrical installation above 1 kV, when approaching an unacceptably small distance V. Action of atmospheric electricity during gas discharges VI. Releasing a person under tension Touch voltage is the potential difference between points in an electrical circuit that a person touches at the same time, usually at the points where the arms and legs are located. The step voltage is the potential difference j1 and j2 in the field of current spreading over the earth's surface between points located at a step distance (» 0.8 m). grounding; zeroing; protective shutdown. In our case, an artificial protective grounding device is used. All equipment, as well as the racks in which this equipment is located, are subject to grounding. A ground loop must be laid around the perimeter of the room where the equipment is located in order to protect people and equipment from static electricity. Protective grounding should be carried out in accordance with the PUE and SNiP 3.05.06-85 (“Electrical devices”). Cases of electric shock to a person are possible only when the electrical circuit is closed through the human body, or, in other words, when a person touches at least two points of the circuit between which there is some voltage. The occurrence of electrical injury as a result of exposure to electric current or electric arc may be due to: a) single-phase (single-pole) touch of a person not isolated from the ground (base) to non-insulated current-carrying parts of electrical installations under voltage; b) with simultaneous contact of a person with two current-carrying non-insulated parts (phases, poles) of electrical installations under voltage; c) when a person approaches a dangerous distance to non-insulated live parts of electrical installations that are energized; d) with a touch of a person who is not isolated from the ground (base) to the metal cases (body) of electrical equipment that is energized; e) with the inclusion of a person who is in the zone of spreading of the earth fault current, to the "step voltage"; e) with the action of atmospheric electricity during lightning discharges; g) with the action of an electric arc; h) with the release of a person who is 1-axis under tension. The severity of electrical injuries, estimated by the magnitude of the current passing through the human body, and the voltage of contact, depends on a number of factors: schemes for connecting a person to a circuit; network voltage, the scheme of the network itself, the degree of isolation of current-carrying parts from the ground, as well as the capacitance of current-carrying parts relative to the ground. The most widely used installations with voltages up to 1000 V with a solidly grounded neutral of a transformer or generator. A four-wire network with a solidly grounded neutral allows you to have two operating voltages: linear 380 V and phase 220 V. There is a three-wire, with an isolated neutral during normal operation, it is less dangerous, and in emergency mode, a network with a grounded neutral is safer, therefore, in conditions where there is an aggressive environment and it is difficult to maintain insulation in good condition, preference is given to a four-wire network with a grounded neutral. At voltages above 1000 V, it is allowed to use three-phase networks: three-wire with isolated neutral and three-wire with grounded neutral. With regard to AC networks, the inclusion of a person in an electrical network can be single-phase and two-phase. Two-phase switching, i.e. a person touching two phases at the same time, as a rule, is more dangerous, since the greatest voltage in a given network is applied to the human body - linear, which depends only on the mains voltage and human resistance, does not depend on the neutral mode I., \u003d 1.73Uf / Rch \u003d Ul / R where 1n is the value of the current passing through the human body, A; U, - linear voltage, i.e. voltage between the phase wires of the network, V; Uph - phase voltage (voltage between the beginning and end of one winding or between the phase and neutral wires), V. Two-phase switching is equally dangerous in a network with both isolated and grounded neutrals. Single-phase switching occurs much more often, but is less dangerous than two-phase, since the voltage under which a person finds himself does not exceed the phase one, i.e. less than linear by 1.73 times. Accordingly, the current passing through the person is less. With a single-phase connection, the current value is also affected by the neutral mode of the current source, the insulation resistance and capacitance of the wires relative to the ground, the resistance of the floor on which the person stands, the resistance of his shoes, and some other factors. The single-phase network can be isolated from earth or have a ground wire. Classification of premises and buildings according to the degree of explosion and fire hazard. ONTP 24–85 All premises and buildings are divided into 5 categories: B - premises where technological processes are carried out using flammable liquids with a flash point above 28 ° C, capable of forming explosive and flammable mixtures, when ignited, an excess design explosion pressure of more than 5 kPa is formed. tVSP > 28 °С; P - over 5 kPa. B - premises and buildings where technological processes are used using combustible and hardly combustible liquids, solid combustible substances, which, when interacting with each other or atmospheric oxygen, can only burn. Provided that these substances do not belong to either A or B. This category is flammable. D - premises and buildings where technological processes are used using non-combustible substances and materials in a combustible, hot or molten state. D - premises and buildings where technological processes are used using solid non-combustible substances and materials in a cold state. The main causes of fires are: short circuit, overload of wires/cables, formation of transient resistances. Short circuit mode - the appearance as a result of a sharp increase in current strength, electric sparks, particles of molten metal, electric arc, open flame, ignited insulation. Causes of a short circuit: design errors. insulation aging. moisture insulation. mechanical overload. Fire hazard during overloads - excessive heating of individual elements, which can occur due to design errors in the event of a long passage of current exceeding the rated value. At 1.5 times the power, the resistors heat up to 200-300 ˚С. Fire hazard of transitional resistances - the possibility of ignition of insulation or other nearby combustible materials from the heat that occurs at the place of emergency resistance (in transitional terminals, switches, etc.). Fire danger of overvoltage - heating of current-carrying parts due to an increase in the currents passing through them, due to an increase in overvoltage between individual elements of electrical installations. Occurs when the parameters of individual elements fail or change. Fire hazard of leakage currents - local heating of the insulation between individual current-carrying elements and grounded structures. construction planning. technical. ways and means of extinguishing fires. organizational. Construction and planning are determined by the fire resistance of buildings and structures (the choice of construction materials: combustible, fireproof, difficult to burn) and the fire resistance limit is the amount of time during which the load-bearing capacity of building structures is not violated under the influence of fire until the first crack appears. All building structures according to the fire resistance limit are divided into 8 degrees from 1/7 hour to 2 hours. For the premises of the EC, materials with a resistance limit of 1–5 degrees are used. Depending on the degree of fire resistance, the greatest additional distances from exits for evacuation in case of fires are determined (grade 5 - 50 minutes). Technical measures are the observance of fire safety standards during the evacuation of ventilation, heating, lighting, electrical supply systems, etc. use of various protective systems. compliance with the parameters of technological processes and equipment operation modes. Organizational measures - conducting fire safety training, compliance with fire safety measures. Decreased concentration of oxygen in the air. Lowering the temperature of a combustible substance below the ignition temperature. Isolation of a combustible substance from an oxidizing agent. Extinguishing agents: water, sand, foam, powder, gaseous substances that do not support combustion (freon), inert gases, steam. A. Chemical foam fire extinguishers. V. foam fire extinguisher. C. powder fire extinguisher. D. carbon dioxide fire extinguisher, ethyl bromine. Fire fighting systems. A. water supply system. B. foam generator. Automatic fire extinguishing system using automatic signaling means. A. fire detector (heat, light, smoke, radiation). V. for the CC, thermal sensors-detectors of the DTL type, smoke, radioisotope type RID are used. Manual fire extinguishing system (push-button detector). For VC, carbon dioxide fire extinguishers OU, OA are used (they create a jet of sprayed ethyl bromine) and automatic gas fire extinguishing systems that use freon or freon as an extinguishing agent. To extinguish a fire with water, sprinklers and deluge devices are used in the automatic fire extinguishing system. Their disadvantage is that spraying occurs on an area of up to 15 m².
The issue of ensuring the safety of employees of firms and enterprises is still relevant to this day, which is primarily due to the fact that over the past years the unfavorable situation in industry with labor protection has been aggravated, and in the OS - with the quality of the natural environment. The number and scale of man-made emergencies are growing. In industry, the level of industrial injuries and occupational diseases is growing. The scale of air pollution is also on the rise. The growth in the scale of production activities, the expansion of the scope of technical systems, the automation of production processes lead to the emergence of new unfavorable factors in the production environment, the consideration of which is a necessary condition for ensuring the required performance and maintaining the health of workers. Therefore, the project considered possible damaging, dangerous and harmful factors of the production environment, also described the methods and means of ensuring the safety of workers, the main measures for electrical safety, environmental protection, prevention of fires and accidents in the premises and elimination of the consequences of emergencies. In connection with the above, I believe that the project is safe for the environment and human health due to the following factors: Reliable operation of a large number of devices on the same network is ensured using token passing technology; Stable operation of the network without failures and interruptions is ensured by the use of the entire operating frequency range for information transmission The number of technical means for organizing a communication channel is minimal (UE - in a single building) Mica coupling capacitor is not explosive The design of the equipment ensures operation in temperature conditions from -40°С to 85°С with humidity up to 95% And besides the above, the network based on PLC technology does not require maintenance during operation. Today, PLC technology is an interesting and useful product, located in a special niche, the use of which in some cases can give a good economic result. The most promising areas of application of solutions: Organization of communication in a cottage or apartment using a ruler Organization of communication in small coaxial networks in rural areas and towns using the Access or In-home line Organization of communication to territorially remote settlements via medium-voltage lines at a distance of 1 km using the Access MV line. But the use of PLC solutions so popular in the West for organizing communications in various administrative buildings may encounter problems caused by the specifics of building and maintaining domestic power grids. I would like to once again remind you of the need to strictly observe safety rules. Work on electrical networks must be carried out by people who have been instructed and have received the appropriate permit. Understanding the Precautions Given the dynamics of the market development, it can be expected that over the next year and a half, broadband PLC technologies can be widely used in a wide variety of industries - from telemetry of utility network resources to multifunctional intelligent systems for individual rooms. After the completion of work on the main international standards, it is likely that PLC adapters will be integrated into almost all household appliances that provide for the possibility of exchanging data with the “outside world”. Given that there are only two main fixed-line operators in the Czech Republic, the telecommunications services market is not fully occupied, and the use and application of PLC technology as it develops will allow both existing providers and new participants to become one of the leaders in this market segment. Simply put, having a small capital, you can create a very promising and competitive organization for the provision of broadband access to the Internet. 1. Savin A.F. PLC is no longer exotic. Messenger of communication 2. Pavlovsky A. Solomasov S. PLC in Russia. Specifics, problems, solutions, projects. InformCourierCommunication. 3. Nevdyaev L.M. Bridge to the Internet over power lines. InformCourierCommunication. 4. Kurochkin Yu.S. "PLC comes to Russia". connect. 5. Konoplyansky D.K. PLC - data transmission over electrical networks. Last mile. 6. Duffy D. BPL is gaining momentum. Networks. 7. Morrisi P. Implementation of BPL technology. Networks and communication systems. 8. Report “PLC technology and its prospects in the Russian market of broadband subscriber access”, Modern Telecommunications company. 9. Electrical work. In 11 books. Book. 8. Part 1. Overhead power lines: Proc. manual for vocational schools / Magidin F.A.; Ed. A. N. Trifonova. - M.: Higher school, 1991. - 208 with ISBN 5-06-001074-0 10. "PLC-5 ControlNet Programmable Controllers" - Allen-Bradley 11. "Life safety" 2009 onwards R.A. Gazarov, R.S. Erzhapova, H.E. Taymaskhanov, M.S. Khasikhanov, 12. "Finance of the enterprise" E.B. Tyutyukin. 13. http://www.dchizhikov.boom.ru/works/PlanPLC.htm (Internet through an outlet - analysis of the product offer on the PLC modem market. Dmitry Chizhikov) 14. http://www.mrcb.ru/kpk.html?25614 15. http://network.xsp.ru/5_5.php 16. http://ru.wikipedia.org - electronic encyclopedia 17. http://www.datatelecom.ru/technology/plc.html 18. http://www.tellink.ru 19. https://www.corinex.com 20. http://www.bosfa.energoportal.ru/srubric16008-1.htm
|
| Standard | Modulation | Range frequencies, kHz |
Quantity subcarriers |
Maximum exchange rate data, kBaud |
|---|---|---|---|---|
| IEC 61334 | SFSK | 60…76 | 2 | 1,2…2,4 |
| PRIME | OFDM | 42…90 | 97 | 128 |
| G3 | OFDM | 35…90 | 36 | 34 |
| G3-FCC | OFDM | 145…314 | 36 | 206 |
| 314…478 | 36 | 206 | ||
| 145…478 | 72 | 289 | ||
| P1901.2 | OFDM | 35…90 | 36 | 34 |
| P1901.2 - FCC | OFDM | 145…314 | 36 | 217 |
| 314…478 | 36 | 217 | ||
| 145…478 | 72 | 290 | ||
| PLC Lite | OFDM | 35…90 | 49 | 21 |
Table 2. Regulatory instructions
| Region | Instruction | Frequency range, kHz | Notes |
|---|---|---|---|
| Europe | CENELEC A | 3…95 | for electricity suppliers |
| CENELEC B | 95…125 | ||
| CENELEC C | 125…140 | for custom applications (CSMA standard) | |
| CENELEC D | 140…148,5 | for custom applications | |
| USA | FCC | 10…490 | — |
| Japan | ARIB | 10…450 | — |
| China | EPRI | 3…500 (3…90) | — |
PRIME
The PRIME Alliance has developed a standard with the ability to adapt to the parameters of the physical transmission medium. It has been experimentally found that 96 subcarriers are needed to achieve optimal data transmission results. The network topology is tree-like, with two types of nodes - basic (the root of the network tree) and service nodes. Service nodes are capable of operating in two modes - a terminal and a switch, and switching between modes is possible at any time, depending on network requirements, and the switch mode combines the terminal mode. There can be a total of 1200 nodes in the network, 32 of which can be in switch mode, and up to 3600 connections are addressed.
The main advantage of this standard is the open technology, high data transfer rate and support by a huge number of manufacturers, which ensures the interchangeability of equipment, as well as the ability to work in SFSK mode, ensuring compatibility with older equipment.
G3
Unlike PRIME, the G3 standard was originally developed by Maxim Integrated for the French company ERDF, and only later more than ten companies merged into the G3-PLC Alliance, which made G3 open.
G3 has a more complex coding system (Reed-Solomon code), a mesh network topology with a maximum number of nodes - 1024. The standard is more noise-resistant than PRIME, but the data transfer rate is significantly lower.
In addition to topology and speed, G3 has two major advantages over PRIME: the first is the ability to communicate through transformers. Considering that the communication range without repeaters can reach 10 km, this feature reduces the number of hubs to the maximum effective number, which reduces the overall cost of the project.
The second feature is the presence of the 6LoWPAN layer, which allows the transmission of IPv6 packets for integration with the Internet.
G3 does not support SFSK devices, but allows parallel operation with them on the same line.
PLC Lite
In addition to international standards, there are other solutions. Texas Instruments offers its own PLC-Lite standard.
The advantage of this standard is a more flexible approach to PLC implementation, hardware designers can optimize performance to improve data transfer, and where G3 and PRIME are struggling due to interference, PLC-Lite will succeed. In addition, the PLC-Lite implementation has a low cost, which allows it to be used in low-cost projects.
There is another important feature of PLC-Lite: for small tasks, the use of a PLC-modem microcontroller is provided, which eliminates the need for a host controller. This simplifies the development of devices and reduces the cost so much that it becomes economically possible to integrate PLC modems into the network at the household level "switch - light bulb". One of the projects showing the effectiveness of such a solution will be described below.
Hardware implementation
To implement this technology, PLC modems are used, which can be conditionally divided into three components: a matching module with a power network, analog and digital parts. The implementation of modems is diverse - there are both single-chip solutions and multi-element ones. Figure 1 shows a typical OFDM PLC modem (FSK and G3 will additionally require a Zero-Cross detector).
Rice. one.
To provide analog signal processing, TI offers ICs AFE030 , AFE031 and AFE032, which differ in the value of the output current load of the transmitter, the number of phase zero crossing detectors (two for AFE030 and AFE031, three for AFE032) and the ability to program the filter (AFE032). These ICs allow FSK, SFSK and OFDM modulation to be implemented in accordance with CENELEC requirements. A block diagram of microcircuits using the example of AFE031 is shown in Figure 2, and detailed functionality and features are described in our magazine earlier: NE No. 10/2012: "Any protocol - over the wire: Texas Instruments solutions for PLC data transmission systems" and NE No. 7/2011: "Concert for the meter and network: Texas Instruments PLC modems."
Rice. 2. Block diagram of AFE031 - analog part of the PLC modem
The “brain” of the modem is a TI C2000 family microcontroller optimized for operation in PLC modems as a DSP. Currently, TI offers several solutions based on regional requirements and standards and taking into account the optimal parameters required. For example, if an extensive network of an energy metering data collection system is required in accordance with CENELEC and G3 and / or PRIME standards, then a PLC modem based on F28PLC83 in conjunction with the analog block AFE031 , the same solution using FlexOFDM (PLC-Lite) will allow communication in conditions of strong interference. If a relatively simple point-to-point system is required, then the pair F28PLC35/AFE030 PLC-Lite standard is the best fit. In particular, the F28PLC35/AFE030 is ideal for building interconnections within a single facility, such as controlling/automating lighting, water supply, and other systems.
Of course, solutions can be used in combination, for example, the inexpensive F28PLC35/AFE030 can be used to transfer data from the energy meter to the home display and to the data collector, the more powerful one - from the collector to the data center.
Table 3 shows the comparative characteristics of the above solutions.
Table 3 TI PLC Modem Solutions
| Peculiarities | F28PLC35/AFE030 (PLC Lite) | F28PLC83/AFE031 (CEN-A/BCD) | F28M35 /AFE032 (FCC) |
|---|---|---|---|
| Regional frequency range | CELENC A, CENELEC BCD half band | CENELEC A, B, C, D with Tone Masks | CENELEC A, B, C, D, FCC, ARIB |
| Standard | FlexOFDM | PRIME/G3/IEC 61334/FlexOFDM | P1901.2/G3-FCC |
| Transmission speed data, kBaud |
21 | 64…128 | 200 |
| Price | very low | low | average |
| CPU, MHz | 60 | 90 (VCU-I) | 150 (VCU-I) |
| Advantages | low cost reliable OFDM flexible ranging high performance NBI CLA for CSMA/CA MAC applications | many standards SW certified improved reception algorithm simple user interface | many standards high performance additional methods of reliability Adaptive Tone Mask proven in practice |
| Use | In-Home Display (IHD) Home Area Network (HAN) | Automatic Meter Reading (AMR) Advanced Metering Infrastructure (AMI) In-Home Display (IHD) (Home Area Network) HAN Energy Gateway | Automatic Meter Reading (AMR) Advanced Metering Infrastructure (AMI) Electric Vehicle Supply Equipment (EVSE) In-Home Display (IHD) (Home Area Network) HAN Energy Gateway |
Practical use
The ability to seamlessly integrate PLC technology virtually anywhere there is a power grid has opened up a wide range of opportunities for utility companies to implement customer management and customer feedback. Equipping metering devices with PLC-modems will allow:
- simplify fiscal;
- collect statistics on the quality and quantity of energy supply with a very accurate reference to time;
- predict energy supplies;
- assess the condition of the lines;
- promptly intervene in the current state, for example, carry out priority connection of consumers in emergency situations;
- reduce the likelihood of emergencies due to “targeted preventive action” in the maintenance of power transmission lines.
At the moment, there is a need for meters for housing and communal services of various types. TI is ready to offer various solutions (including software and debugging tools) that allow you to build a "smart" network for almost any requirement (Figure 3). Let's consider a practical example of energy metering based on these solutions.
Rice. 3.
Typically, houses have at least three meters - an electricity meter and two water meters. However, there can be many more of them: there are projects of houses where there is gas supply, water supply is supplied twice, which requires already four meters. And, if there are no special problems with the electric meter, then with the rest it is necessary to make a reliable connection using a different interface. And the existence of each counter individually in the network does not seem practical. Add the need for an emergency shutdown of power supply systems (and abroad - also shutdown at the end of payment) - this will require additional sensors and actuators. In addition, the end user is extremely curious about how much, where, when and what was spent, and the ability of the "smart" network to provide him with such information is much higher than that of a simple counter. This means that a module for displaying information is needed. And now let's multiply all this by a certain number of apartments in the house, area ...
Therefore, an important element is present in the automated measurement infrastructure (AMI) - the data concentrator (Figure 4).
Rice. 4.
Conventionally, the hub module can be divided into four parts: the main application processor, a communication module with a data server (and with some meters) based on a PLC modem, a power supply and interface modules for communicating with meters and users via a variety of different interfaces.
The hub is based on a TI processor of the family SitaraAM335x(ARM Cortex-A8) or families Stellaris(Cortex-M4) or ARM-DSP, which allows the developer to choose the optimal cost solution depending on the technical conditions.
A large number of interfaces at the data concentrator will allow collecting data from meters or providing communication with the server where the use of PLC technology for some reason turned out to be impossible.
Thanks to the ability of the TI PLC modem processor to execute custom applications, the scheme of an automated metering system becomes quite simple, and its construction is very flexible: the electric meter, together with the PLC modem and additional interfaces, is able to collect data from other meters, control actuators and display information for user. Figure 5 shows a typical electric meter solution designed for wide versatility.
Rice. 5.
Typical solutions for gas and water supply meters are based on TI series microcontrollers MSP430 , characterized by low current consumption, which makes battery power possible. Figures 6 and 7 show that, in addition to the basic measurement, display and communication systems, there is an RFID module. which provides the mode of advance payment for gas and water supply services.
Rice. 6.
Rice. 7.
In addition to the ability to monitor readings directly on the meters, the smart network has an In-Home Display - a central information display (Figure 8), thanks to which there is no need to check each meter individually, everything can be seen at once. This allows you to install meters more conveniently and / or not violate the design of the house - as a rule, in normal cases, either access to the meter is difficult, and reading becomes a problem for the user, or the meter becomes an unattractive part of the interior.
Rice. eight.
Equipping housing and communal services with systems of this kind allows you to get many positive aspects:
- centralized collection of information on the amount of energy consumed from all network users allows you to issue invoices in a timely manner indicating the exact amount, introduce various tariff systems and implement preventive and restrictive measures when the limit is exceeded or energy consumption rules are violated;
- better allocation of funds for the modernization and repair of systems based on information about failures in energy consumption systems and needs at individual sites;
- the ability to quickly localize and resolve emergency situations.
In addition, the system is so flexible that it allows you to make significant additions without any global rebuilding. For example, the integration of gas leak sensors into the system will make it possible to introduce preventive measures to ensure safety.
Unfortunately, the implementation of such a system requires the resolution of serious organizational issues (and some capital investments) on the part of power supply companies and housing and communal services. However, such a system fully justifies its existence for the sake of user convenience.
Automation of measurements is just one of the applications of PLC technology. An important part is the possibility of automated control of various systems, such as lighting, ventilation, electric drives for gates and blinds, alternative power supply systems (Figure 9).
Rice. nine.
The TI data concentrator's microcontroller capabilities provide a range of convenient, and sometimes necessary, control options:
- control and management of all systems;
- remote connection via the Internet;
- automatic switching on of lighting according to a calendar or a sensor;
- automatic connection of an emergency power source with "smart" connection of consumers;
- selective or general shutdown of systems in emergency situations;
- remote control from the remote control (for example, opening the garage door).
Of course, there are alternative solutions: own solutions of manufacturers of lighting, electric gate drives, etc. The advantage of a solution based on PLC components from TI is the ability to integrate into an existing facility without any significant changes, as well as its versatility.
Ultimately, a single control is much simpler, more reliable and more convenient (a good example is two options for audio-video equipment: one manufacturer with a single control panel and several different ones, with an appropriate number of remote controls), and makes it possible to easily expand the system.
In some cases, using PLC modems may be the only simple and cost-effective solution at all. Consider the following typical example: cottage, living room with four entry points (street, courtyard, stairs to the second floor, kitchen). Turning on the lighting in the living room becomes problematic - a cheap solution (one switch) is just inconvenient. It is convenient to have four crossover switches, one at each entry point. This will allow you to control the lighting from any point without making unnecessary movements (when turned off - in the dark). But for implementation, it is necessary to conduct three wires to two switches, and four to two more.
And this is the control of one lamp. If there are two or more groups of lamps in the chandelier, the number of wires increases dramatically. The cost of a two-key cross switch, even without taking into account the cost of wires, is already comparable to the cost of a PLC modem. The cost of installation of such a system is also quite high. Let's try to create the same system with the ability to adjust the brightness, and we will have to integrate something remote directly into the lamp.
The use of a TI PLC modem eliminates the need to lay additional cables, moreover, it makes you look at the classical system in a slightly different way: the PLC modem as a switch and regulator can be integrated not only into the switch connection point, but also into the line of sockets . The connection of the lamps is also simplified (no wiring with switches required). The number and nature of lamp control becomes irrelevant. The design of switches (regulators) gets limitless possibilities. In addition, integration into a common "smart" network allows you to implement an emergency lighting system without laying a single additional cable.
TI debugging tools
For PLC-based system development, TI offers the following:
- MODEM DEVELOPER'S KIT
- TMDSDC3359
The TMDSPLCKIT-V3 set includes two PLC-modems, two control cards based on TMS320F28069 , has a built-in USB-JTAG emulator and all necessary cables. Also included is PLC software that supports OFDM (PRIME, G3 and FlexOFDM) and S-FSK standards, and Code Composer Studio v4.x development environment with a 32 kB executable code size limit. Used analog signal processing chip - AFE031 . The appearance of one of the modems is shown in Figure 10.
Rice. ten.
Data Concentrator Evaluation Module TMDSDC3359(Fig. 11). This product allows you to debug data concentrator based systems. Built on the AM335x processor of the Sitara ARM Cortex-A8 family with OC Linux BSP. The board has a wide periphery:
- 2x USB;
- 2x Ethernet;
- 2x RS-232;
- 3x RS-485;
- infrared transceiver;
- temperature sensor;
- Sub-1GHz and 2.4GHz RF; AM335x.
Rice. eleven.
It is possible to connect a module for communication via three-phase networks. The switching power supply is built-in.
Supported standards - G3, PRIME.
Conclusion
The use of PLC technology for data transmission has many advantages, allowing you to quickly and cost-effectively deploy a "smart" network that can quickly adapt to the required tasks, and thanks to the capabilities of the G3 and PRIME standards - to the data transmission environment.
Texas Instruments provides a complete solution, from chips to software, for implementing PLC networks in control and information systems. Due to its flexibility, this solution allows the implementation of the system for any type of protocol and satisfies the possible requirements of regulatory regulations.
COMPEL is an official distributor of Texas Instruments and can provide developers with both processors and analog microcircuits, as well as development tools for implementing their own PLC projects.
Literature
4. Andrey Samodelov. Concert for the meter and the network: Texas Instruments PLC modems//News of Electronics No. 7/2011.
5. Alexey Pazyuk. Any protocol over the wire: Texas Instruments solutions for PLC data transmission systems//News of Electronics No. 10/2012.
Obtaining technical information, ordering samples, delivery - e-mail:
TI's Bluetooth Smart SensorTag makes it easy to develop Bluetooth applications on AndroidTM 4.3 devices
Company Texas Instruments announced the launch of an Android application called Bluetooth Smart Sensor Tag, following the integration of Bluetooth Smart Ready app support into Android 4.3 "Jelly Bean". New product available for free download at www.ti.com/sensortag-app-android-eu removes barriers to app developers wanting to take advantage of the millions of Android smartphones and tablets that will soon be equipped with Bluetooth Smart Ready. Developing a block of Bluetooth Smart apps, now supported by Android and iOS, is easier and faster with a developer kit Sensor Tag on the base CC2541. The kit includes six sensors for a wide range of applications, placed on a single board for quick evaluation and demonstration. For more information about the Sensor Tag kit, go to www.ti.com/lprf-stdroid-pr-eu.
The Sensor Tag Kit requires no software or hardware knowledge to quickly launch Bluetooth Smart apps on your smartphone or tablet. Developers share their Sensor Tag achievements on the Texas Wiki page ( http://processors.wiki.ti.com/index.php/Bluetooth_SensorTag?DCMP=lprf-stdroid-eu&HQS=lprf-stdroid-pr-wiki1-eu) and on Twitter using the #SensorTag hashtag.
Six built-in sensors of the Sensor Tag set, including a non-contact infrared temperature sensor TMP006 from TI help develop numerous applications in areas such as healthcare and education, as well as create new accessories for mobile devices. The kit runs free, over-the-air upgradeable BLE-Stack TM software from TI. The CC2541-based Sensor Tag complements TI's other dual-mode Bluetooth CC2564 and WiLink TM solutions.
About Texas Instruments
Communication technologies and standardsLON is a local operating network. To implement smart home networks, network technologies that appeared in 1998, such as LonWorks, HomeRF and Bluetooth, are used.
home radio network Home RF It is made on the basis of an open industrial protocol for collective wireless access (Shared Wireless Acess Protocol - SWAP), developed by a working group of manufacturers of home RF systems (Home Radio Frequency Working Group - HomeRF). The group, formed in March 1998, brought together more than 90 manufacturers (including Intel). The frequency band used is 2.4 GHz with frequency hopping capability. The network operates with a noise-like signal (NLS) and supports a data rate of 2 Mbps over a distance of up to 50 m. Products such as the AnyPoint series from Intel and HomeLINE from Farallon are on the market. AnyPoint includes an adapter for connecting multiple PCs via a USB port to the nearest telephone jack.
Popular Bluetooth platform designed for the 2.45 GHz band. It provides for the use of a frequency hopping transceiver (1600 hops/s) and operation in the time multiplex mode. In the range from 10 cm to 10 m, the data rate is 1 Mbps. The range is short, but can be increased to 100 m by increasing the power of the transmitted signal
