With the passing of years and the continual technical development of materials and components, the electrical system in civil buildings, and not only has integrated its role as a simple distribution of electricity with modern technology Home and Building Automation (HBA), better known by the term Domotics. This word is composed of a set of words: “domus“, which in Latin means house, and “robotics” the discipline of engineering that deals with methods that allow a machine to realize the human labor. Specifically, the development of all those technologies to improve the quality of life in all the inhabited places.
Actually the Home Automation covers all automation systems involving a single house, providing services mainly to people who generally do not have great familiarity with sophisticated electronic equipment. This is the reason why generally, the home automation is composed of devices that do not require particular technical expertise; consider, for example, elderly or disabled people who can use all the features of a system through a simple remote control or voice commands.
Instead, the Building Automation covers all automation systems related to the management of entire buildings in residential (large condos, hotels), manufacturing (factories) in public (hospitals, schools), commercial (shops, malls). The Building Automation is aimed mainly at professionals with special expertise and for these reasons, it manages functionality technically much more complex and advanced.
Through the combined use of electrical, electronics, IT and telecommunications, Domotics researches and develops integrated systems for the automation of processes and controls. With these systems, we can achieve a better quality of life, enhanced security, and above all, a considerable saving in energy consumption (see Fig.1).
The features that can be automated through the use of a home automation system, can be distinguished in the following categories:
- management and control of cargo: all appliances so-called “white”, i.e. refrigerators, ovens, washing machines, dishwashers, water heaters, etc. belong to this category. In addition to the management and diagnosis, also the remote control is possible for each load;
- environmental management: this category includes lighting, climate control and water management. For example, for lighting you can adjust the intensity of artificial light in the interior as a function of natural light by raising or lowering blinds or curtains outside. you can adjust the luminous intensity of a light point as a function of an event such as switching on the television. For air conditioning, you can coordinate the system heating or cooling with artificial ventilation or with the opening and closing of windows. In this way you allow the adjustment of the temperature of each environment regardless of weather conditions on the outside. For water management, you can program over time and depending on the weather conditions the irrigation of gardens, plants and greenhouses;
- security management: this category includes the activities of intrusion detection and video surveillance, protection from fire, gas leaks and flooding, automatic requests for assistance by telephone especially in the case of old people living alone or at risk;
- information management and communication: this category includes the intercom, telephone, fiber optics, and satellite TV reception, the sound system, the remote services (teleservices). With the use of a home automation system, for example, you can listen anywhere in your house a radio or see on a dvd on a monitor, or direct and/or record telephone calls and/or on certain television equipment.
The Domotic System
The main feature of a home automation system is to use a wide range of devices capable of communicating with each other within an intelligent management system that includes all the global system types: electrical, electronic, hydraulic, alarm and video surveillance, fire , data.
Consequently, the fundamental element that characterizes this type of system is the communication network or a system consisting of a physical line of communication that connects the various components referred to the transmission medium, or more generally BUS from the Latin “omnibus”, which means ‘for all’ (in fact you should pronounce it as ‘boos‘ because it is a latin word). Furthermore, a digital part will constitute the language of communication, called communication protocol.
In practice, a home automation system is composed of a BUS line which by means of a digital communication protocol, it allows the dialogue between the following categories of devices (see figure 2):
- output devices. They are specific electronic interfaces which, through appropriate components, are used by the user to implement the monitoring and implementation of the various needs such as turning on the lights, set the temperature, turn on watering plants, etc..They control devices such as switches, buttons, switches, radio programmers, touch-screens and sensor devices that collect signals from the environment such as temperature sensors, gas leak, flooding, anemometers, etc.;
- input devices. They are specific electronic interfaces called actuators that collect the signals from the output devices. They interface with the power grid with the various system components such as the power of the lights, opening doors and windows, turning on or turning off of appliances, activating a pump shutoff system or the closing of a solenoid valve in case of gas leaks.
The advantages of a home automation system are several: the physical separation between the power lines and the command lines, the simplicity of installation and connections, and the significant reduction in the quantity of cables used, but the most important is undoubtedly the possibility to change the configuration at any time without affecting the connections.
In fact, exploiting the potential of communication protocol, just a “name” (address) is assigned to each device in the system, so that each component knows what to do and when to do but more importantly, it knows which are the devices with which must do it.
In this way, for example, you can change at any time the function of a switch or the actions of a sensor simply by reprogramming the addresses to which commands are sent. A switch can be a diverter or a light sensor may act either on the rolling shutter or on a lighting twilight of the garden, simply by reprogramming the system.
The home automation systems are classified according to their architecture, or to the way in which the various devices are connected and controlled as well as the function of the control unit, in the following types:
- centralized. In this type of architecture, there is only one central control unit. The controls are managed solely by the central unit based on the programming of its internal memory. The various devices connected to the system are not able to communicate with each other, the information coming from the sensors and the commands and that are directed to the actuators, are always managed by the unit of centralized control ( see Figure 3);
- distributed. In this type of architecture, all devices have its own intelligence for which are able to perform certain functions autonomously. A name (address) is uniquely assigned to each device, in this way through a communication protocol, all devices are able to communicate with each other allowing the realization of certain features (see Figure 4);
- mixed. It associates a centralized control unit to a series of central derived spread in the building that communicate between them. This architecture is very efficient, but very complex, especially suitable for building automation (Figure 5).
The Transmission Medium
The transmission medium, most commonly defined BUS (Binary Unit System), is the system used for the physical connection of all devices of a home automation system. In general, the choice of the most suitable transmission medium must be made according to the analysis of the environment in which the connection must be carried out, or to its extension, to the speed of response to commands, noise immunity, not neglecting a right compromise between cost and performance of the system.
The transmission media for the possible creation of a home automation network are:
- PL, Power Line. It consists in the use of the distribution network of the electricity that powers the various plant components. In practice, the voltage of the distributed network is modulated with the signals to be transmitted, therefore all components of the system are connected between phase and neutral through suitable decoupling interfaces . The communication is bidirectional, but the transmission in the two directions can not be simultaneous, for this reason, the transmission speed is significantly low. This system is particularly suitable in the case of existing installations, where it would not be possible to install new cables. By contrast, this system is potentially very unstable, the electrical network, in fact, is subject to distortion and unpredictable disturbances which make it necessary to adopt special line filters on the implant. The connection rules are laid down in EN 50065-1 standard “Signal transmission on low voltage electrical networks in the frequency range (3 kHz – 148,5 kHz) – Part 1: General requirements, frequency bands and electromagnetic disturbances”;
- RF, Radio Frequency. By means of this technology it is possible to transmit information between a component and the other without a physical connection but using electromagnetic waves typically 433 MHz, 868 MHz and 2.4 GHz frequency modulated. For example through the standard Wi-Fi, ZigBee, Bluetooth. This system is particularly suitable for structures of artistic value which would be problematic in any installation of walls or in the case of minor changes in existing structures. By contrast, its limitations lie in the fact that the usable frequency bands are not yet standardized worldwide. Adequate security is still not guaranteed because communication can be easily disturbed and most importantly, the level of electromagnetic pollution would increase significantly within the housing;
- IR, Infra Red. It is a system of wireless link that uses electromagnetic waves in the infrared field, together with the advantage of the absence of a physical connection, it has the disadvantage of unidirectional communication and strong attenuation in the presence of obstacles;
- Optical fiber. It is constituted by thin and lightweight glass fibers that exploit the transmission and modulation of light (LED or laser). It is totally immune to electromagnetic interference and is particularly suitable for connecting great distances allowing the construction of very large networks at high speed. By contrast, the fiber optic cables as very delicate and complex connections require special and expensive steps during the installation, also their cost is considerably high.
- TP, Twised Pair: It is constituted by a pair of insulated copper conductors between them. It shall ensure, besides the exchange of information between the various components also to their power supply. The most widely used solution is a twisted pair cable helical (twisted) with a longer wheelbase and shielded to prevent the information in transit along the cable are disrupted by electromagnetic interference. In relation to the presence or absence of shielding, twisted pairs are distinguished (see Figure 6) in: UTP (Unshielded Twisted Pair); FTP (foiled twisted pair); STP (Shielded Twisted Pair); S-FTP (Shielded Foiled Twisted Pair).
The system bus twisted pair is the one that brings out the full potential of home automation systems, so as to be the most widely used means of transmission, reliable, easy to install, with a good transmission speeds in excess of 100 Mb / s and above with costs considerably lows.
It should be clear, however, that the bus line of a home automation system must not be considered as a data transmission line for telecommunications and multimedia distribution, characterized by a certain band width and capable of transmitting complex information at high speed, but is a line that needs to transmit information of limited quality and low speed.
In this regard, the standard EN 50090-9-1 “Home and Building Electronic System” defines the following classes HBES for bus lines:
- class 1 ensures the requirements for the transmission of commands and controls;
- class 2 ensure the requirements of class 1 plus the audio and video transmission at low speed;
- class 3 adds the transmission of complex video signals at high speed to the requirements of class 2;
In the current home automation systems, bus lines of class 1 and 2 are used exclusively. Class 1 is used to control lighting, heating, cooling, ventilation or intrusion alarms, flood, gas, fire; while class 2 is used for telephone, intercom and video intercom, sound system, video control.
The communication protocol
The communication system, more commonly defined language, with which the various components of the domotic system interact with each other through the medium of transmission is called communication protocol. It can be of type:
- owner. It is a communication protocol managed exclusively by the manufacturer of the equipment that does not make available any information on its operating characteristics. For this reason it can communicate with equipment from other manufacturers only with the use of specific interfaces provided by the operator of the same protocol. In general it is very cheap systems that are used for distribution of small and medium size;
- standardized or open. It is a communication protocol open to any manufacturer and allows full interoperability of components. That is, the operating specifications of the devices are made in the public domain so that any manufacturer may decide to make devices interoperating with this protocol. A standardized protocol, in general, is managed by a third party (a consortium of several companies) that deals with the technical development as well as also the certification of producers and components. In practice, these systems are very complex and sophisticated communication systems that make possible the construction of large systems.
There is currently a large number of communication protocols, the main ones are listed below:
- Bluetooth. Born in 1998 from the collaboration between IBM, Intel, Ericsson, Nokia and Toshiba, it is mainly used by major manufacturers of electronic and computer equipment. Also known as IEEE 802.15.1 standard, it uses a transmission system with radio frequency 2.4 GHz It can communicate at a maximum distance of a few tens of meters at a speed of 1 Mb / s;
- Ethernet. Born at an experimental level in the 70s, its specifications have been established with the IEEE 802.3 standard. This protocol uses as a means of transmitting optical fiber and twisted-pair cable and can communicate with a speed up to 1 Gb / s. It is mainly used in industry for the control of large automated systems. Recently, especially after the spread of the Internet, it is also used in the residential field for the creation of local networks;
- X-10. It is a protocol on the market for over twenty years and is particularly common in the United States. It is a one-way system availability with up to 256 devices. It uses as a medium of transmission the conveyed waves on the electrical low voltage system. The system for remote control uses infrared remote controls. This protocol is very slow (60 bits per second) but very simple to install and to use;
- ZigBee. Known as IEEE 802.15.4 protocol, in practice, it is the evolution of Bluetooth, therefore characterized by security and the ability to support a large number of devices. By contrast, it has a very low communication speed;
- Jini. It is a software technology derived from Java with which it is possible auto-configuration. Each device contains the system software with which you can communicate with all the other components. The system is considered to be devoid of a central monitoring organization, in practice composed of many independent entities but able to communicate with each other;
- UPnP (Universal Plug and Play) It is developed by Microsoft and allows multiple devices to communicate with each other or through interface equipment such as computers and / or decoders;
- HBS (Home Bus System) Realized by a consortium of Japanese companies in 1988, it uses a transmission medium rather complex, consisting of two coaxial cables and eight twisted pairs. It can handle any domestic apparatus with particular regard to audio and video devices;
- LonWorks. It is also known as ANSI / EIA 701.9-A-1999. A single network can support up to 32 000 different devices. In addition to the automation HBES, it is used for example in industrial and commercial by Enel with the new smart meters for measuring electricity consumption and teleservices, for control of the elevators, in the diagnosis of printed circuit boards, in medical instrumentation and fire protection;
- Konnex (KNX). It is a consortium formed in 1999 by collaboration between EIBA (European Installation Bus Association), BCI (Batibus Club International) and EHSA (European Home Systems Association) with the aim of creating a comprehensive and standardized system for the control and management of the automation in residential, commercial and industrial buildings. It is not tied to a single supplier or a single industry.
The KNX standard (Konnex)
Among the many protocols listed above, the KNX standard is the one that has imposed itself most in the world market. He is currently the most important and widespread in the sector of the commercial and residential; with over 300 manufacturers and over 15,000 certified devices, it is a system of communication and certification that is recognized worldwide.
KNX was founded in 1999 by the Konnex foundation formed by the merger of three European associations: EIB (European Installation Bus), BCI (Batibus Club International), EHSA (European Home Systems Association). This standard is based primarily on the specific EIB further complemented with some configuration mechanisms developed by BCI and EHSA. It uses the twisted pair, the carrier waves at 110 kHz and 132 kHz, the radio frequency 868 MHz and the infrared rays as a means of transmission.
It is currently recognized as the standard in accordance with the European CENELEC EN50090 and IEC 13321-1, since 2006 it has been approved as an international standard in accordance with ISO / IEC 14543-3 standard and is also approved as Chinese GB / Z 20965.
Once you have finished installing all the components of the system, ie after you have completed all the connections of the bus line and all electrical connections of the various users, you must activate the process of communication between the various devices by performing a specific task configuration. This is possible by using a special software called ETS (Engineering Tool Software currently, originally called the EIB Tool Software) that is an integral part of the KNX standard by which you can make, in addition to the initial configuration and commissioning, diagnostics and also monitoring the system regardless of the manufacturer of the devices.
The software is marketed by the consortium KNX ETS in three versions:
- Demo: this version can be used free of charge only for small test projects;
- Lite: light version with limited functions for the realization of small/medium projects;
- Professional: professional version, complete with all the features for the construction of large and very large systems.
Through the ETS software installed on a computer, you can set the configuration regardless of the system on which you are operating, ie without being connected to the bus line (offline). Once you have finished configuring your computer, you can connect to the system through the appropriate interface, such as RS232, USB, Ethernet, etc., and upload it, thus allowing the system to operate independently. The operation is the same, if you need to make changes to an existing system or control.
The consortium KNX through rigorous checks certifies and guarantees, as well as the various manufacturers, components that are certified on the basis of three configuration modes:
- S-Mode (System Mode). It is a very advanced configuration mechanism that requires highly specialized personnel. Through the use of the ETS software, it is suitable for the realization of complex systems with sophisticated control functions.
- E-Mode (Easy Mode). Components with this configuration mode are made with a set of default parameters that allow a rapid and easy installation, even by personnel with a limited technical knowledge.
- A-Mode (Automatic Mode). It is a configuration mechanism that includes devices that can automatically configure itself without the intervention of highly experienced technicians, and for this reason they are used directly by the end user.
The structure of a KNX system (see figure 8) is composed of various devices grouped into lines belonging to a number of areas connected to each other through the transmission medium; each line can be grouped up to 64 devices, each area can be composed of a maximum of 15 lines and each system can include up to 15 areas, as a consequence to every single system you can connect up to 14,400 devices.
The various lines are connected to the mains through the line couplers AL, while the main lines can be connected to each other through the area couplers AA. The couplers have the function to electrically isolate parts of the system in such a way that a possible electrical failure of a single device does not compromise the functioning of the entire system. The connection between the lines and the ridge can be made either in any way (see Figure 9), however, it must comply with the following conditions of the KNX standard:
- maximum length of a single line 1000 m;
- maximum number of devices on a single line: 64;
- maximum distance between two devices: 700 m;
- maximum distance of a device with respect to the power supply: 350 m;
- maximum number of power supplies for each line: 2, placed at 200 m from each other;
- in the presence of 30 or more devices connected on a bus line length of less than or equal to 10 m, you have necessary to place the power supply in the immediate vicinity.
The KNX standard divides the devices into two categories:
– System devices are power supplies with safety extra low voltage 24 V DC and the various couplers, all those devices that carry out activities in support of the system;
– Dedicated devices allow the implementation of the functionality of the system such as sensors, controls, actuators. These devices are composed of two separate units: a unit exclusively functional such as the button or a probe for light intensity or for the speed of the wind, and the other unit exclusively electronic named BCU (Bus Coupling Unit) which is directly connected with the bus line enables the exchange and interpretation of signals between the functional unit and the rest of the system.
The unit BCU is a real micro computer comprising: a microprocessor; an EEPROM (Electronically Erasable Programmable Memory) that manages the configuration parameters; a ROM (Read Only Memory) that runs the operating system; a RAM (Random Access Memory) that controls and manages the status of the device; a transmission module that allows the decoupling of signals from supply (see figure 10).
The Konnex communication protocol is based on digital data transmission of the serial type in which the information is formed by the sequence of bits (the smallest element in the binary number system, the sequence of 8 bits form one byte) each of which can assume the value of 1 or 0. In practice, the logic state 1 is equal to the value of the supply voltage of the system, while the logic state 0 is equivalent to the reduction in the value of the supply voltage with a pulse duration of 35 ms. The communication takes place with sending messages called telegrams in the presence of any event such as the pressing of a button or the state of a sensor (see Figure 11).
In the interval T1 the device checks that the bus line is not engaged by other telegrams. At the end of the transmission of the message, the receiving device verifies the proper receipt with the time T2 and with a positive verification it sends the confirmation. In case the message is not received correctly its transmission can be repeated up to three times, if the reception of the telegram is not confirmed, the procedure is aborted and is registered in the memory of the sender.
Each telegram consists of several fields divided into packets of 8 bits plus some information to verify transmission errors; in practice a telegram consists of the following fields in order:
- control field contains control information for the receiving device in order to manage the telegram traffic;
- address field contains the name of the device that sends the telegram and the device to which it is intended;
- data field contains the instructions to be executed as a command or a detection or alarm;
- security field contains the information of verification of the security for a telegram, in order that it is not raised constinuosly;
- confirmation field contains the information about the correct reception of the message by the recipient.
In order to avoid unnecessary repetitions if the bus line is busy or with an alarm message, the system is able to assign a priority status to telegrams in the following order:
- LOW no priority, normal message with low priority;
- HIGH for shortcuts, medium priority;
- ALLARM for alarm messages, high-priority;
- SYSTEM messages for system management, very high priority.
An overview of the standards
The regulatory system in respect of the Home and Building Electronic System involves the following organizations:
- CENELEC with the TC205;
- ISO/IEC JTC 1/SC 25 “Interconnection of information technology equipment”;
- CEI with the CT205 “Bus systems for buildings”;
The most important regulations regarding HBES (Home and Building Electronic System) is the CENELEC EN 50090 (implemented in Italy as CEI EN 50090), which is divided into nine sections. It states: the requirements of the system and components; the criteria for the design, installation, verification and testing (see here).
Other technical reference standards are:
- CEI 0-2 Guide for the definition of project documentation of electrical systems;
- CEI 64-8 Electrical plant using low voltage. Systems for the distribution of electricity;
- CEI 64-50 Guide for the integration of electrical systems in the building users and the provision of auxiliary facilities, telephone and data transmission services;
- CEI 64-100-1-2 Guide for the preparation of the infrastructure for the electrical, electronic and communications;
- CEI 79-3 Detection and reporting intrusion detection systems, theft, sabotage and aggression;
- CEI 83-11 Guide for bus systems in buildings for valuable historical and artistic importance;
- IEC 100-7 Guide for the application of the rules on television receiving equipment;
- IEC 103-1 PABX;
- IEC 205-2 Guide for bus systems for the automation of pair in the house and buildings, according to CEI EN 50090;
- IEC 205-14 Guide for design, installation and testing facilities HBES;
- IEC 205-18 Guide for the use of automation of the technical installations in buildings. Identification of functional schemes and estimation of the contribution to the reduction of the energy demand of a building;
- IEC 205-24 General requirements for electronic systems for the home and building (HBES) and automation systems and building control (BACS);
- IEC 306-2 Guide for cabling for telecommunications and multimedia distribution in residential buildings;
- IEC 306-6 Generic cabling systems. General requirements and offices;
- IEC 50173-1 Information technology – Structured cabling systems – General requirements;
- IEC 50173-4 Information technology – Structured cabling systems – residential;
- IEC 50174-1 Information technology – Cabling Installation – Specifications and Quality Assurance;
- IEC 50174-2 Information technology – Cabling Installation – Planning and installation criteria in buildings;
- UNI 9795 Fixed systems automatic detection, signaling and manual fire alarm.
The evolution of the electrical system design
With the use of home automation, it is no longer enough to realize a correct dimensioning and wiring to ensure the functionality of an electric system, but also a correct programming is required. Compared to conventional (and obsolete) electrical installations, a home automation system offers significant advantages providing all the users of the system with control functions, comfort and safety, ensuring a better quality of life by integrating the following features:
- management of heating, cooling and ventilation;
- management of electrical loads with detachment of non-priority (washing machine, oven, etc..) upon successful completion of the used power;
- on, off and automatic adjustment of the intensity of illumination of the environment;
- automatic creation of predefined scenarios;
- opening or closing of curtains and blinds according to outside weather conditions;
- monitoring of the premises remotely via cameras; management of technical alarms (fire, intruder, flooding, gas leaks);
- telephony management;
- management of sound and television broadcasting;
- control and monitoring of energy efficiency through reading, display and parameterization of the counters values with accounting, graphics processing and historical consumption;
- management of alarm zones;
- control of circuit breakers installed in switchboards.
As a result of this rapid technological change also the design of an electrical system has undergone a radical transformation from a simple design electrical systems, it has become integrated plant design. In particular, we speak of integrated plant design when there is no longer a clear separation between the different types of plant installed in a building. The result is a unique programmable multifunction system able to monitor, coordinate and control the various functions both locally and remotely. In traditional systems the various designers operate independently of each other. In the case of a home automation system should be an effective and constant interaction between the various plant configurations and consequently between different installers, the electrician, the plumber, the fabricator, the antenna installer, the electronics technician, and the IT technician..
The spread of increasingly sophisticated electronic equipment in the home has become an unstoppable phenomenon that makes it crucial task of continuous coordination between the different system designs that should be taken by the home automation designer (System Integrator), with responsibilities primarily electric but also oriented to the management of the house, telecommunications, security of persons and property, to entertainment, heating and plumbing, computer.
In practice, the professional designer home automation (System Integrator) is the natural evolution of the traditional electrical designer. This new professional must be fully aware of the technology needs of all plants of a given building ensuring a perfect harmony with all the other professionals in order to obtain the best possible solutions and above all protect the buyer from easy and cheap solutions are not standardized .
The phases of the integrated systems design
The task of a good home automation designer is to correct sizing of lines and protections and also to implement a procedure for the execution of the project that must be performed according to the order of the following steps:
- analysis of the needs and requirements of the customer. At this preliminary stage, you must apply directly to distributors of services in such a way as to bring out clearly all the necessities and functionality to satisfy. Indeed, at this stage, errors of evaluation and possible misunderstandings involve erroneous designs and accordingly incorrect installation of the systems;
- assessment of the systems and their components. At this stage you have to prepare an accurate list of all the systems and related equipment to install highlighting all the arrangements for monitoring and control of various functions in order to avoid inconsistencies and incompatibilities between the installations and the control system;
- choice of the home automation system. In this stage, all the components of the automation system must be chosen, the central command and control with possible future expansions, the transmission medium, the communication protocol, the devices for input and output. The choices made must achieve a balance between the needs to be met, the functional characteristics of the system and costs;
- elaboration of the project. At this stage the positions of the devices are defined (switchboards, control panels, controllers, actuators, sensors, video surveillance equipment, etc.) and planimetric layout are made with the arrangement of all equipment and controls, junction boxes, of electrical panels, control stations with their schemas. The circuit diagrams of the paintings are defined and the calculation of the power lines and the guards takes place; you also define any details on installation, strictly dependent on the complexity of the project;
- map of signals and commands, the connection diagram. In this stage, you have to provide appropriate tables in order to define the addresses of all the devices input and output of the system and its connections, taking into account all the needs and functions required by the customer;
- specifications and requirements for the planning and maintenance of the system. At this stage you have to prepare all the documentation necessary for a correct programming and commissioning of the system and the requirements for routine maintenance of the system.
Some Useful Tips
With the continuous technology development worldwide, especially in the context of electrical, continuous adaptation to modern technology is required in order to implement more sophisticated systems to comply with regulatory requirements relating in particular to achieve significant energy savings. In this regard, there is no doubt about the many benefits that can be achieved with the construction of a home automation system; For these reasons in the design and installation, it is advised that you respect the following recommendations:
- carefully evaluate the use of the actuators and their connection to the load which of course it must be as short as possible, this in order to avoid junction boxes with an excessive number of actuators and sometimes useless;
- during the laying of cables, you should apply a correct and indelible nomenclature to power lines and communication. Very often in the vicinity of paintings and boxes, you are faced with an indistinct tangle of cables with the inability to perform any operation, especially in the case of a possible modification;
- The power supply lines for the various utilities such as lamps, sockets groups, motors, etc., must be brought directly on the loads and must be protected by one or more electrical panels exactly as it happens for a traditional system respecting the current regulations that govern low-voltage electrical systems. Instead, there are no rules that require that the bus connection to twisted pair is made in a dedicated pipeline. However, it is necessary to ensure compliance with the regulatory requirements relating to insulation voltage of the different cables in the same pipe;
- due to the fact that a home automation system, unlike a traditional system, cannot be operational until the final programming, it is advisable to use actuators with the function of manual operation to enable a functional test of the electric lines before the final programming of the system . In this way, any malfunction can be attributed only to programming errors;
- In the light of the new standard IEC 64-8, the seventh edition, which also introduces requirements for the systems made with home automation solutions, the continued spread of plants for the production of energy from renewable sources such as photovoltaic, together with the IEC 0 – 21 concerning the technical regulation for connection of active and passive users to networks of low-voltage electricity distribution companies; it is evident that the realization of the classic general electric panel 12/24 DIN modules generally located to the left of the entrance door is no longer sufficient, but it is necessary to make use of a real technical room where to arrange and manage all the devices that the standards require that the modern plant and make available to the designer and installer. The surface of the technical room must obviously be a function of the surface extension of the entire system and its complexity, especially in the presence of various control units and other control devices (load control, video surveillance, TV, video, intrusion, fire, spread sound, data distribution, etc..). In particular it must be able to contain at least, as minimum equipment: two paintings wall for the mounting of equipment up to 24 DIN modules on each row, one exclusively dedicated to the distribution of power and one for the distribution of the commands, controls, signals TV, data, telephone, technical alarms; in order to operate properly said technical room will be easily accessible, indicated by a special sign on the door and possibly be located in the vicinity of the main entrance is compatible with the architectural requirements;
- the realization of a home automation system is extremely rational but also very costly in terms of susceptibility of the plant. Therefore, it is not advisable to use this solution in the case of restructuring while it is certainly very advantageous in the case of new installation. When you have to act on an existing installation, you should carefully evaluate all possible offers of the various manufacturers: the market could offer solutions of which at the moment you are not aware;
- an integrated plant design can be considered properly made only if is not limited exclusively to the momentary needs, so it is a good idea to implement it in order to allow ease with its possible future evolution. For example in the design of electrical cabinets and control is preferable to use casings with a percentage of free modules greater than that provided by the regulations, while in the laying of pipes,
it is good to provide some pipes free especially in the main distribution.
- Unlike a traditional electrical system where each function refers to a separate wiring and especially dedicated (for example, a switch can control only the circuit on which it is installed or an anemometer can control only the outside curtains) in a home automation system do not exist functions so selective. By means of efficient programming of the addresses, the capacity and especially the experience of the designer is able to exploit the possibilities of intelligent conversation between the various devices in an advantageous manner. For example the information of a sensor can be used for a wide range of tasks. This makes an efficient home automation system is not the result of the quantity and quality of the components installed but is exclusively the result of the ability of the designer.