Building automation ( BAS ), also known as building management system ( BMS ) or building energy management system ( BEMS ), is the automatic centralized control of a building's HVAC (heating, ventilation and air conditioning) , electrical, lighting , shading, access control , security systems , and other interrelated systems. Some objectives of building automation are improved occupant comfort, efficient operation of building systems, reduction in energy consumption, reduced operating and maintaining costs and increased security.
85-399: BAS functionality may keep a buildings climate within a specified range, provide light to rooms based on occupancy, monitor performance and device failures, and provide malfunction alarms to building maintenance staff. A BAS works to reduce building energy and maintenance costs compared to a non-controlled building. Most commercial, institutional, and industrial buildings built after 2000 include
170-537: A phase converter having single-phase converter input and three-phase inverter output. Controller advances have exploited dramatic increases in the voltage and current ratings and switching frequency of solid-state power devices over the past six decades. Introduced in 1983, the insulated-gate bipolar transistor (IGBT) has in the past two decades come to dominate VFDs as an inverter switching device. In variable- torque applications suited for Volts-per-Hertz (V/Hz) drive control, AC motor characteristics require that
255-554: A 2015 survey done by iControl, the primary drivers of the demand for smart and connected devices are first "personal and family security", and second "excitement about energy savings". Home automation includes a variety of smart security systems and surveillance setups. This allows consumers to monitor their homes while away, and to give trusted family members access to that information in case anything bad happens. While there are many competing vendors, there are increasing efforts towards open source systems. However, there are issues with
340-422: A BAS, whilst older buildings may be retrofitted with a new BAS. A building controlled by a BAS is often referred to as an intelligent building, a "smart building", or (if a residence) a " smart home ". Commercial and industrial buildings have historically relied on robust proven protocols (like BACnet ) while proprietary protocols (like X-10 ) were used in homes. With the advent of wireless sensor networks and
425-560: A BMS typically represent 40% of a building's energy usage; if lighting is included, this number approaches to 70%. BMS systems are a critical component to managing energy demand. Improperly configured BMS systems are believed to account for 20% of building energy usage, or approximately 8% of total energy usage in the United States. In addition to controlling the building's internal environment, BMS systems are sometimes linked to access control (turnstiles and access doors controlling who
510-557: A VFD system is usually a three-phase induction motor . Some types of single-phase motors or synchronous motors can be advantageous in some situations, but generally three-phase induction motors are preferred as the most economical. Motors that are designed for fixed-speed operation are often used. Elevated-voltage stresses imposed on induction motors that are supplied by VFDs require that such motors be designed for definite-purpose inverter-fed duty in accordance with such requirements as Part 31 of NEMA Standard MG-1. The VFD controller
595-440: A VFD, the stopping sequence is just the opposite as the starting sequence. The frequency and voltage applied to the motor are ramped down at a controlled rate. When the frequency approaches zero, the motor is shut off. A small amount of braking torque is available to help decelerate the load a little faster than it would stop if the motor were simply switched off and allowed to coast. Additional braking torque can be obtained by adding
680-621: A braking circuit (resistor controlled by a transistor) to dissipate the braking energy. With a four-quadrant rectifier (active front-end), the VFD is able to brake the load by applying a reverse torque and injecting the energy back to the AC line. Many fixed-speed motor load applications that are supplied direct from AC line power can save energy when they are operated at variable speed by means of VFD. Such energy cost savings are especially pronounced in variable-torque centrifugal fan and pump applications, where
765-558: A broader category, includes any device that can be monitored or controlled via wireless radio signals, not just those having internet access. When connected with the Internet, home sensors and activation devices are an important constituent of the Internet of Things ("IoT"). A home automation system typically connects controlled devices to a central smart home hub (sometimes called a " gateway "). The user interface for control of
850-409: A conveyor application for smoother deceleration and acceleration control, which reduces the backlash that can occur when a conveyor is accelerating or decelerating. Performance factors tending to favor the use of DC drives over AC drives include such requirements as continuous operation at low speed, four-quadrant operation with regeneration, frequent acceleration and deceleration routines, and need for
935-423: A frequency of pulses accordingly. Controllers are essentially small, purpose-built computers with input and output capabilities. These controllers come in a range of sizes and capabilities to control devices commonly found in buildings, and to control sub-networks of controllers. Inputs allow a controller to read temperature, humidity, pressure, current flow, air flow, and other essential factors. The outputs allow
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#17327765847271020-409: A given appliance, leading to overall positive environmental impacts and lower electricity bills for the consumers using the system. To do this, researchers propose using data from sensors regarding consumer activity within the home to anticipate consumer needs and balance that with energy consumption. Furthermore, home automation has a large potential regarding family safety and security. According to
1105-694: A high cost of ownership, inflexibility of interconnected devices, and poor manageability. When designing and creating a home automation system, engineers take into account several factors including scalability, how well the devices can be monitored and controlled, ease of installation and use for the consumer, affordability, speed, security, and ability to diagnose issues. Findings from iControl showed that consumers prioritize ease-of-use over technical innovation, and although consumers recognize that new connected devices have an unparalleled cool factor, they are not quite ready to use them in their own homes yet. Historically, systems have been sold as complete systems where
1190-611: A larger failure. Some sites are programmed so that critical alarms are automatically re-sent at varying intervals. For example, a repeating critical alarm (of an uninterruptible power supply in 'bypass') might resound at 10 minutes, 30 minutes, and every 2 to 4 hours thereafter until the alarms are resolved. Security systems can be interlocked to a building automation system. If occupancy sensors are present, they can also be used as burglar alarms. Because security systems are often deliberately sabotaged, at least some detectors or cameras should have battery backup and wireless connectivity and
1275-450: A leak), or when excess methane is detected in the building's air supply. Most building automation networks consist of a primary and secondary bus which connect high-level controllers (generally specialized for building automation, but may be generic programmable logic controllers ) with lower-level controllers, input/output devices and a user interface (also known as a human interface device). ASHRAE 's open protocol BACnet or
1360-399: A load upon command. An example would be to turn on the parking lot lights when a photocell indicates it is dark outside. Another example would be to open a valve by allowing 24VDC/AC to pass through the output powering the valve. Analog outputs could also be pulse type outputs emitting a frequency of pulses over a given period of time. An example is an energy meter calculating kWh and emitting
1445-497: A means for an operator to start and stop the motor and adjust the operating speed. The VFD may also be controlled by a programmable logic controller through Modbus or another similar interface. Additional operator control functions might include reversing, and switching between manual speed adjustment and automatic control from an external process control signal. The operator interface often includes an alphanumeric display or indication lights and meters to provide information about
1530-637: A potentially hazardous or costly situation if no one who can solve the problem is notified. Notification can be through a computer (email or text message), pager , cellular phone voice call, audible alarm, or all of these. For insurance and liability purposes all systems keep logs of who was notified, when and how. Alarms may immediately notify someone or only notify when alarms build to some threshold of seriousness or urgency. At sites with several buildings, momentary power failures can cause hundreds or thousands of alarms from equipment that has shut down – these should be suppressed and recognized as symptoms of
1615-517: A problem for security , data security and data privacy , since patches to bugs found in the core operating system often do not reach users of older and lower-price devices. One set of researchers say that the failure of vendors to support older devices with patches and updates leaves more than 87% of active devices vulnerable. Concerns have been raised by tenants renting from landlords who decide to upgrade units with smart home technology. These concerns include weak wireless connections that render
1700-406: A pure electrical means of communication. Typical means of hardwired communication are: 4-20mA , 0-10VDC, or using the internal 24VDC power supply with a potentiometer . Speed can also be controlled remotely and locally. Remote control instructs the VFD to ignore speed commands from the keypad while local control instructs the VFD to ignore external control and only abide by the keypad. Depending on
1785-610: A smart light setup, one participant thought that her iPad communicated directly with the light, telling it to either turn-off or on. In reality, the iPad sends a signal to the cloud system that the company uses (in this case, the Hue Bridge) which then signals directly to the device. Overall, this field is still evolving and the nature of each device is constantly changing. While technologists work to create more secure, streamlined, and standardized security protocols, consumers also need to learn more about how these devices work and what
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#17327765847271870-413: A stand-alone AC system) into a central building automation system. Terminal unit controllers usually are suited for control of lighting and/or simpler devices such as a package rooftop unit, heat pump, VAV box, fan coil, etc. The installer typically selects one of the available pre-programmed personalities best suited to the device to be controlled, and does not have to create new control logic. Occupancy
1955-534: A step-up transformer is placed between a LV drive and a MV motor load. MV drives are typically rated for motor applications greater than between about 375 and 750 kW (503 and 1,006 hp). MV drives have historically required considerably more application design effort than required for LV drive applications. The power rating of MV drives can reach 100 MW (130,000 hp), a range of different drive topologies being involved for different rating, performance, power quality, and reliability requirements. It
2040-487: A variable measurement. Examples are temperature , humidity and pressure sensors which could be thermistor , 4–20 mA , 0–10 volt or platinum resistance thermometer (resistance temperature detector), or wireless sensors . A digital input indicates a device is on or off. Some examples of digital inputs would be a door contact switch, a current switch, an air flow switch , or a voltage-free relay contact (dry contact). Digital inputs could also be pulse inputs counting
2125-436: A wide range of single-phase and multi-phase AC motors. Low-voltage (LV) drives are designed to operate at output voltages equal to or less than 690 V. While motor-application LV drives are available in ratings of up to the order of 5 or 6 MW, economic considerations typically favor medium-voltage (MV) drives with much lower power ratings. Different MV drive topologies (see Table 2) are configured in accordance with
2210-546: Is a solid-state power electronics conversion system consisting of three distinct sub-systems: a rectifier bridge converter, a direct current (DC) link, and an inverter. Voltage-source inverter (VSI) drives (see 'Generic topologies' sub-section below) are by far the most common type of drives. Most drives are AC–AC drives in that they convert AC line input to AC inverter output. However, in some applications such as common DC bus or solar applications, drives are configured as DC–AC drives. The most basic rectifier converter for
2295-509: Is a subset of building automation and with a similar purpose; it is the consolidation of one or more systems under centralized control, though in this case in one room. The most common example of room automation is corporate boardroom, presentation suites, and lecture halls, where the operation of the large number of devices that define the room function (such as videoconferencing equipment, video projectors , lighting control systems , public address systems etc.) would make manual operation of
2380-538: Is a typical function of a BAS, as is the more sophisticated ventilation and humidity monitoring required of "tight" insulated buildings. Most green buildings also use as many low-power DC devices as possible. Even a passivhaus design intended to consume no net energy whatsoever will typically require a BAS to manage heat capture , shading and venting, and scheduling device use. Building management systems are most commonly implemented in large projects with extensive mechanical, HVAC, and electrical systems. Systems linked to
2465-416: Is allowed access and egress to the building) or other security systems such as closed-circuit television (CCTV) and motion detectors. Fire alarm systems and elevators are also sometimes linked to a BMS for monitoring. In case a fire is detected then only the fire alarm panel could close dampers in the ventilation system to stop smoke spreading, shut down air handlers, start smoke evacuation fans, and send all
2550-400: Is also often available to allow the VFD to be configured, adjusted, monitored, and controlled using a computer. There are two main ways to control the speed of a VFD; networked or hardwired. Networked involves transmitting the intended speed over a communication protocol such as Modbus , Modbus / TCP , EtherNet/IP , or via a keypad using Display Serial Interface while hardwired involves
2635-596: Is constructed from intersections of a saw-toothed carrier signal with a modulating sinusoidal signal which is variable in operating frequency as well as in voltage (or current). Operation of the motors above rated nameplate speed (base speed) is possible, but is limited to conditions that do not require more power than the nameplate rating of the motor. This is sometimes called "field weakening" and, for AC motors, means operating at less than rated V/Hz and above rated nameplate speed. Permanent magnet synchronous motors have quite limited field-weakening speed range due to
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2720-414: Is drawing less than 50% of its rated current from the mains in the low-speed range. A VFD can be adjusted to produce a steady 150% starting torque from standstill right up to full speed. However, motor cooling deteriorates and can result in overheating as speed decreases such that prolonged low-speed operation with significant torque is not usually possible without separately motorized fan ventilation. With
2805-443: Is estimated that drive technology is adopted in as many as 30–40% of all newly installed motors. An energy consumption breakdown of the global population of AC motor installations is as shown in the following table: AC drives are used to bring about process and quality improvements in industrial and commercial applications' acceleration, flow, monitoring, pressure, speed, temperature, tension, and torque. Fixed-speed loads subject
2890-450: Is needed. This can save money by using less chilled or heated water (not all AHUs use chilled or hot water circuits). Some external air is needed to keep the building's air healthy. To optimize energy efficiency while maintaining healthy indoor air quality (IAQ) , demand control (or controlled) ventilation (DCV) adjusts the amount of outside air based on measured levels of occupancy. Analog or digital temperature sensors may be placed in
2975-490: Is one of two or more operating modes for a building automation system; Unoccupied, Morning Warmup, and Night-time Setback are other common modes. Occupancy is usually based on time of day schedules. In Occupancy mode, the BAS aims to provides a comfortable climate and adequate lighting, often with zone-based control so that users on one side of a building have a different thermostat (or a different system, or sub system) than users on
3060-531: The IEEE 1905.1 standard and verified by the nVoy auditing mark. These accommodate typically only IP-based networking but can make use of any existing wiring, and also integrate powerline networking over AC circuits, power over Ethernet low-power DC circuits, high-bandwidth wireless networks such as LTE and IEEE 802.11n and IEEE 802.11ac and often integrate these using the building-specific wireless mesh open standard Zigbee . Proprietary hardware dominates
3145-488: The field bus Digital Addressable Lighting Interface (DALI). Lamps with DALI ballasts are fully dimmable. DALI can also detect lamp and ballast failures on DALI luminaires and signals failures. Shading and glazing are essential components in the building system, they affect occupants’ visual, acoustical, and thermal comfort and provide the occupant with a view outdoor. Automated shading and glazing systems are solutions for controlling solar heat gains and glare. It refers to
3230-745: The frequency of the input electricity. Depending on its topology , it controls the associated voltage or current variation. VFDs are used in applications ranging from small appliances to large compressors. Systems using VFDs can be more efficient than hydraulic systems , such as in systems with pumps and damper control for fans. Since the 1980s, power electronics technology has reduced VFD cost and size and has improved performance through advances in semiconductor switching devices, drive topologies, simulation and control techniques, and control hardware and software. VFDs include low- and medium-voltage AC–AC and DC–AC topologies. Pulse-Width Modulating (PWM) variable-frequency drive projects started in
3315-550: The pulses over a period of time. An example is a turbine flow meter transmitting flow data as a frequency of pulses to an input. Nonintrusive load monitoring is software relying on digital sensors and algorithms to discover appliance or other loads from electrical or magnetic characteristics of the circuit. It is however detecting the event by an analog means. These are extremely cost-effective in operation and useful not only for identification but to detect start-up transients , line or equipment faults, etc. Analog outputs control
3400-545: The 1960s at Strömberg in Finland. Martti Harmoinen [ fi ] is regarded as the inventor of this technology. Strömberg managed to sell the idea of PWM drive to Helsinki Metro in 1973 and in 1982 the first PWM drive SAMI10 were operational. A variable-frequency drive is a device used in a drive system consisting of the following three main sub-systems: AC motor, main drive controller assembly, and drive/operator interface. The AC electric motor used in
3485-422: The Internet of Things, an increasing number of smart buildings are resorting to using low-power wireless communication technologies such as Zigbee, Bluetooth Low Energy and LoRa to interconnect the local sensors, actuators and processing devices. Almost all multi-story green buildings are designed to accommodate a BAS for the energy, air and water conservation characteristics. Electrical device demand response
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3570-400: The United States, an estimated 60–65% of electrical energy is used to supply motors, 75% of which are variable-torque fan, pump, and compressor loads. Eighteen percent of the energy used in the 40 million motors in the U.S. could be saved by efficient energy improvement technologies such as VFDs. Only about 3% of the total installed base of AC motors are provided with AC drives. However, it
3655-426: The VFD controller. Basic programming of the microprocessor is provided as user-inaccessible firmware . User programming of display , variable, and function block parameters is provided to control, protect, and monitor the VFD, motor, and driven equipment. The basic drive controller can be configured to selectively include such optional power components and accessories as follows: The operator interface provides
3740-722: The VSI drive is configured as a three-phase, six-pulse, full-wave diode bridge . In a VSI drive, the DC link consists of a capacitor which smooths out the converter's DC output ripple and provides a stiff input to the inverter. This filtered DC voltage is converted to quasi- sinusoidal AC voltage output using the inverter's active switching elements. VSI drives provide higher power factor and lower harmonic distortion than phase-controlled current-source inverter (CSI) and load-commutated inverter (LCI) drives (see 'Generic topologies' sub-section below). The drive controller can also be configured as
3825-466: The ability to trigger alarms when disconnected. Modern systems typically use power-over-Ethernet (which can operate a pan-tilt-zoom camera and other devices up to 30–90 watts) which is capable of charging such batteries and keeps wireless networks free for genuinely wireless applications, such as backup communication in outage. Fire alarm panels and their related smoke alarm systems are usually hard-wired to override building automation. For example: if
3910-544: The chart's four quadrants are defined as follows: Most applications involve single-quadrant loads operating in quadrant I, such as in variable-torque (e.g. centrifugal pumps or fans) and certain constant-torque (e.g. extruders) loads. Certain applications involve two-quadrant loads operating in quadrant I and II where the speed is positive but the torque changes polarity as in case of a fan decelerating faster than natural mechanical losses. Some sources define two-quadrant drives as loads operating in quadrants I and III where
3995-430: The constant magnet flux linkage . Wound-rotor synchronous motors and induction motors have much wider speed range. For example, a 100 HP, 460 V, 60 Hz, 1775 RPM (4-pole) induction motor supplied with 460 V, 75 Hz (6.134 V/Hz), would be limited to 60/75 = 80% torque at 125% speed (2218.75 RPM) = 100% power. At higher speeds, the induction motor torque has to be limited further due to
4080-665: The consumer relies on one vendor for the entire system including the hardware, the communications protocol, the central hub, and the user interface. However, there are now open hardware and open source software systems which can be used instead of or with proprietary hardware. Many of these systems interface with consumer electronics such as the Arduino or Raspberry Pi, which are easily accessible online and in most electronics stores. In addition, home automation devices are increasingly interfaced with mobile phones through Bluetooth, allowing for increased affordability and customizability for
4165-427: The contactor thus turns on the drive and has it output to a designated speed. Depending on the sophistication of the drive multiple auto-starting behavior can be developed e.g. the drive auto-starts on power up but does not auto-start from clearing an emergency stop until a reset has been cycled. Referring to the accompanying chart, drive applications can be categorized as single-quadrant, two-quadrant, or four-quadrant;
4250-497: The control of daylight and solar energy to enter into built environment in relation to outdoor conditions, daylighting demands and solar positions. The common products include venetian blinds , roller shades , louvers , and shutters. They are mostly installed on the interior side of the glazing system because of the low maintenance cost, but also can be used on the exterior or a combination of both. Most air handlers mix return and outside air so less temperature/humidity conditioning
4335-764: The controller market. Each company has controllers for specific applications. Some are designed with limited controls and no interoperability, such as simple packaged roof top units for HVAC. Software will typically not integrate well with packages from other vendors. Cooperation is at the Zigbee/BACnet/LonTalk level only. Current systems provide interoperability at the application level, allowing users to mix-and-match devices from different manufacturers, and to provide integration with other compatible building control systems . These typically rely on SNMP , long used for this same purpose to integrate diverse computer networking devices into one coherent network. With
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#17327765847274420-501: The controller to send command and control signals to slave devices, and to other parts of the system. Inputs and outputs can be either digital or analog. Digital outputs are also sometimes called discrete depending on manufacturer. Controllers used for building automation can be grouped in three categories: programmable logic controllers (PLCs), system/network controllers, and terminal unit controllers. However an additional device can also exist in order to integrate third-party systems (e.g.
4505-406: The current state of home automation including a lack of standardized security measures and deprecation of older devices without backwards compatibility. Home automation has high potential for sharing data between family members or trusted individuals for personal security purposes and could lead to energy saving measures with a positive environmental impact in the future. The home automation market
4590-408: The door or appliance unusable or impractical; the security of door passcodes kept by the landlord; and the potential invasion of privacy that comes with connecting smart home technologies to home networks. Researchers have also conducted user studies to determine what the barriers are for consumers when integrating home automation devices or systems into their daily lifestyle. One of the main takeaways
4675-583: The elevators to the ground floor and park them to prevent people from using them. Building management systems have also included disaster-response mechanisms (such as base isolation ) to save structures from earthquakes. In more recent times, companies and governments have been working to find similar solutions for flood zones and coastal areas at-risk to rising sea levels . Self-adjusting floating environment draws from existing technologies used to float concrete bridges and runways such as Washington's SR 520 and Japan's Mega-Float . Analog inputs are used to read
4760-551: The end of the year 2018. The word " domotics " is a contraction of the Latin word for a home ( domus ) and the word robotics . The word "smart" in "smart home" refers to the system being aware of the state of its devices, which is done through the information and communication technologies (ICT) protocol and the Internet of Things (IoT). Home automation is prevalent in a variety of different realms, including: In 2011, Microsoft Research found that home automation could involve
4845-553: The first general purpose home automation network technology, X10 , was developed. It is a communication protocol for electronic devices. It primarily uses electric power transmission wiring for signalling and control, where the signals involve brief radio frequency bursts of digital data , and remains the most widely available. By 2012, in the United States, according to ABI Research, 1.5 million home automation systems were installed. Per research firm Statista more than 45 million smart home devices will be installed in U.S. homes by
4930-538: The growing spectrum of capabilities and connections to the Internet of Things , building automation systems were repeatedly reported to be vulnerable, allowing hackers and cybercriminals to attack their components. Buildings can be exploited by hackers to measure or change their environment: sensors allow surveillance (e.g. monitoring movements of employees or habits of inhabitants) while actuators allow to perform actions in buildings (e.g. opening doors or windows for intruders). Several vendors and committees started to improve
5015-540: The implications of putting them in their homes can be. The growth of this field is currently limited not only by technology but also by a user's ability to trust a device and integrate it successfully into his/her daily life. Utilizing home automation could lead to more efficient and intelligent energy-saving techniques. By integrating information and communication technologies (ICT) with renewable energy systems such as solar power or wind power, homes can autonomously make decisions about whether to store energy or expend it for
5100-407: The last motion was sensed. A photocell placed outside a building can sense darkness, and the time of day, and modulate lights in outer offices and the parking lot. Lighting is also a good candidate for demand response , with many control systems providing the ability to dim (or turn off) lights to take advantage of DR incentives and savings. In newer buildings, the lighting control can be based on
5185-420: The load's torque and power vary with the square and cube , respectively, of the speed. This change gives a large power reduction compared to fixed-speed operation for a relatively small reduction in speed. For example, at 63% speed a motor load consumes only 25% of its full-speed power. This reduction is in accordance with affinity laws that define the relationship between various centrifugal load variables. In
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#17327765847275270-418: The lowering of the breakaway torque of the motor. Thus, rated power can be typically produced only up to 130–150% of the rated nameplate speed. Wound-rotor synchronous motors can be run at even higher speeds. In rolling mill drives, often 200–300% of the base speed is used. The mechanical strength of the rotor limits the maximum speed of the motor. An embedded microprocessor governs the overall operation of
5355-433: The model a VFD's operating parameters can be programmed via: dedicated programming software, internal keypad, external keypad, or SD card. VFDs will often block out most programming changes while running. Typical parameters that need to be set include: motor nameplate information, speed reference source, on/off control source and braking control. It is also common for VFDs to provide debugging information such as fault codes and
5440-492: The motor to a high starting torque and to current surges that are up to eight times the full-load current. AC drives instead gradually ramp the motor up to operating speed to lessen mechanical and electrical stress, reducing maintenance and repair costs, and extending the life of the motor and the driven equipment. Variable-speed drives can also run a motor in specialized patterns to further minimize mechanical and electrical stress. For example, an S-curve pattern can be applied to
5525-481: The motor to be protected for a hazardous area. The following table compares AC and DC drives according to certain key parameters: ^ High-frequency injection AC drives can be classified according to the following generic topologies: Most drives use one or more of the following control platforms: Variable-frequency drives are also categorized by the following load torque and power characteristics: VFDs are available with voltage and current ratings covering
5610-433: The motor voltage magnitude, angle from reference, and frequency so as to precisely control the motor's magnetic flux and mechanical torque. Although space vector pulse-width modulation (SVPWM) is becoming increasingly popular, sinusoidal PWM (SPWM) is the most straightforward method used to vary drives' motor voltage (or current) and frequency. With SPWM control (see Fig. 1), quasi-sinusoidal, variable-pulse-width output
5695-504: The open protocol LonTalk specify how most such devices interoperate. Modern systems use SNMP to track events, building on decades of history with SNMP-based protocols in the computer networking world. Physical connectivity between devices was historically provided by dedicated optical fiber , ethernet , ARCNET , RS-232 , RS-485 or a low-bandwidth special purpose wireless network . Modern systems rely on standards-based multi-protocol heterogeneous networking such as that specified in
5780-453: The operation of the drive. An operator interface keypad and display unit is often provided on the front of the VFD controller as shown in the photograph above. The keypad display can often be cable-connected and mounted a short distance from the VFD controller. Most are also provided with input and output (I/O) terminals for connecting push buttons, switches, and other operator interface devices or control signals. A serial communications port
5865-536: The opposite side. A temperature sensor in the zone provides feedback to the controller, so it can deliver heating or cooling as needed. If enabled, morning warmup (MWU) mode occurs prior to occupancy. During Morning Warmup the BAS tries to bring the building to setpoint just in time for Occupancy. The BAS often factors in outdoor conditions and historical experience to optimize MWU. This is also referred to as optimized start . Some buildings rely on occupancy sensors to activate lighting or climate conditioning. Given
5950-411: The potential for long lead times before a space becomes sufficiently cool or warm, climate conditioning is not often initiated directly by an occupancy sensor. Lighting can be turned on, off, or dimmed with a building automation or lighting control system based on time of day, or on occupancy sensor, photosensors and timers. One typical example is to turn the lights in a space on for a half-hour since
6035-558: The room very complex. It is common for room automation systems to employ a touchscreen as the primary way of controlling each operation. Smart home Home automation or domotics is building automation for a home . A home automation system will monitor and/or control home attributes such as lighting, climate, entertainment systems, and appliances. It may also include home security such as access control and alarm systems. The phrase smart home refers to home automation devices that have internet access. Home automation,
6120-402: The same polarity. In starting a motor, a VFD initially applies a low frequency and voltage, thus avoiding high inrush-current associated with direct-on-line starting . After the start of the VFD, the applied frequency and voltage are increased at a controlled rate or ramped up to accelerate the load. This starting method typically allows a motor to develop 150% of its rated torque while the VFD
6205-504: The security features in their products and standards, including KNX, Zigbee and BACnet (see recent standards or standard drafts). However, researchers report several open problems in building automation security. On November 11, 2019, a 132-page security research paper was released titled "I Own Your Building (Management System)" by Gjoko Krstic and Sipke Mellema that addressed more than 100 vulnerabilities affecting various BMS and access control solutions by various vendors. Room automation
6290-476: The smoke alarm is activated, all the outside air dampers close to prevent air coming into the building, and an exhaust system can isolate the blaze. Similarly, electrical fault detection systems can turn entire circuits off, regardless of the number of alarms this triggers or persons this distresses. Fossil fuel combustion devices also tend to have their own over-rides, such as natural gas feed lines that turn off when slow pressure drops are detected (indicating
6375-424: The space or room, the return and supply air ducts , and sometimes the external air. Actuators are placed on the hot and chilled water valves, the outside air and return air dampers. The supply fan (and return if applicable) is started and stopped based on either time of day, temperatures, building pressures or a combination. All modern building automation systems have alarm capabilities. It does little good to detect
6460-435: The speed and torque is same (positive or negative) polarity in both directions. Certain high-performance applications involve four-quadrant loads (Quadrants I to IV) where the speed and torque can be in any direction such as in hoists, elevators, and hilly conveyors. Regeneration can occur only in the drive's DC link bus when inverter voltage is smaller in magnitude than the motor back- EMF and inverter voltage and back-EMF are
6545-406: The speed or position of a device, such as a variable frequency drive , an I-P ( current to pneumatics ) transducer , or a valve or damper actuator . An example is a hot water valve opening up 25% to maintain a setpoint . Another example is a variable frequency drive ramping up a motor slowly to avoid a hard start. Digital outputs are used to open and close relays and switches as well as drive
6630-404: The states of the input signals. Most VFDs allow auto-starting to be enabled. Which will drive the output to a designated frequency after a power cycle, or after a fault has been cleared, or after the emergency stop signal has been restored (generally emergency stops are active low logic). One popular way to control a VFD is to enable auto-start and place L1, L2, and L3 into a contactor. Powering on
6715-552: The system uses either wall-mounted terminals, tablet or desktop computers, a mobile phone application, or a Web interface that may also be accessible off-site through the Internet. Early home automation began with labor-saving machines. Self-contained electric or gas powered home appliances became viable in the 1900s with the introduction of electric power distribution and led to the introduction of washing machines (1904), water heaters (1889), refrigerators (1913), sewing machines , dishwashers , and clothes dryers . In 1975,
6800-488: The use of technology to control external or internal shading devices (such as blinds, and shades) or glazing itself. The system has an active and rapid response to various changing outdoor data (such as solar, wind) and to changing interior environment (such as temperature, illuminance, and occupant demands). Building shading and glazing systems can contribute to thermal and lighting improvement from both energy conservation and comfort point of view. Dynamic shading devices allow
6885-621: The user. Home automation suffers from platform fragmentation and lack of technical standards a situation where the variety of home automation devices, in terms of both hardware variations and differences in the software running on them, makes the task of developing applications that work consistently between different inconsistent technology ecosystems hard. Customers may hesitate to bet their IoT future on proprietary software or hardware devices that use proprietary protocols that may fade or become difficult to customize and interconnect. The nature of home automation devices can also be
6970-691: The voltage magnitude of the inverter's output to the motor be adjusted to match the required load torque in a linear V/Hz relationship. For example, for 460 V, 60 Hz motors, this linear V/Hz relationship is 460/60 = 7.67 V/Hz. While suitable in wide-ranging applications, V/Hz control is sub-optimal in high-performance applications involving low speed or demanding, dynamic speed regulation, positioning, and reversing load requirements. Some V/Hz control drives can also operate in quadratic V/Hz mode or can even be programmed to suit special multi-point V/Hz paths. The two other drive control platforms, vector control and direct torque control (DTC), adjust
7055-421: The voltage/current-combination ratings used in different drive controllers' switching devices such that any given voltage rating is greater than or equal to one to the following standard nominal motor voltage ratings: generally either 2 + 3 ⁄ 4 .16 kV (60 Hz) or 3 + 3 ⁄ 6 .6 kV (50 Hz), with one thyristor manufacturer rated for up to 12 kV switching. In some applications
7140-420: Was regarding ease of use, as consumers tend to steer towards "plug and play" solutions over more complicated setups. One study found that there were large gaps in the mental-models generated by users regarding how the devices actually work. Specifically, the findings showed that there was a lot of misunderstanding related to where the data collected by smart devices was stored and how it was used. For example, in
7225-412: Was worth US$ 64 billion in 2022 and is projected to grow to over $ 163 billion in 2028. Variable frequency drive A variable-frequency drive ( VFD , or adjustable-frequency drive , adjustable-speed drive , variable-speed drive , AC drive , micro drive , inverter drive , or drive ) is a type of AC motor drive (system incorporating a motor) that controls speed and torque by varying
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