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Showing posts from March, 2015

Elements of Building Management Systems

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Audio Video System Integration Board Room / Meeting Rooms / Auditorium Public Announcement System Lighting Automation Energy Monitoring and Conservation Curtain Automation Fire Security Systems Surveillance Solutions Access Control Systems Power Trunking Water Management System EPABX, Video Door Phones, Intercom Elevator Control Visitor Management Advantages of Building Automation System (BAS) Centralized control Remote support Reduced complaints Staff optimization Seamless integration Energy savings Increase level of comfort Improved security BAS powers Flexibility & Convenience No location constaint Visualization Parameterization Alarm Monitoring Room Automation Data Point Lights Blinds / Curtains Temperature Sockets / Appliances Motion and Occupation Smoke Doors and Windows contacts Access Control Camera

Protocols used in Lighting Industry

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BACnet BACnet®, short for “Building Automation Control Network”, is a data communication protocol for building automation and control networks. BACnet is both an international (ISO) and ANSI standard for interoperability between cooperating building automation devices. Originally developed in 1987 under the auspices of the American Society of Heating Refrigerating and Airconditioning Engineers (ASHRAE), BACnet has been an ANSI standard since 1995 and an ISO standard since 2003. BACnet is a registered trademark of ASHRAE. BACnet is a standard data communication protocol that enables interoperability between different building systems and devices in building automation and control applications. BACnet offers a flexible range of networking options including the use of Ethernet or IP-centric infrastructure and a simple, low cost twisted pair communication called MS/TP that is based on EIA- 485. A sophisticated routing capability allows scaling of BACnet internetworks into larg...

Mounting Configuration of Occupancy Sensors

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Determining the mounting configuration and location for a Occupancy Sensor is a critical design decision. The mounting configuration ,in particular ,affects the available coverage area. Improper mounting location is a leading cause of application problems with occupancy sensors. Mounting can be done at the following locations: Ceiling High Wall and corner Wall switch( Wall box) Workstation   Ceiling Appropriate for large areas that feature obstacles such as partitions,in addition to narrow spaces such as corridors and warehouse aisles. Units can be networked for control of areas that are larger than what can be controlled be a single sensor. Typically 2-2 times higher installed cost than wall switch sensors but can be economical if controlling large zones. High Wall and Corner Similarly appropriate for coverage of large areas that feature obstacles. Wall Switch (Wall Box) Appropriate for smaller enclosed spaces such as private offices with clear line of...

Light & Vision

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VISION A simple definition of LIGHT is visually perceived radiant energy. This visible light is a small part of the ELECTROMAGNETIC SPECTRUM and ranges in wavelengths from 380 nm to 780 nm. Light is what energizes our visual system. Light reflected from objects  into our eyes enables us to see.Lightwaves enter the human eye and send signals along the optic nerve.Light enters the eye through the pupil, is focused on the retina, and is transmitted to our brain via the optic nerve. A significant part of our brain is dedicated to the processing of visual information. Of all creatures on this earth, the human visual system is the most impressive. Birds may have sharper vision, felines may be more sensitive to motion, and horses may have almost a 360-degree field of view, but nothing can beat the combination of features humans possess. The human eye allows good depth perception, excellent color perception, reasonable motion detection, and great visual acuity. PERCEPTION...

Lighting Design Consideration

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Lighting design is an Art as well as a Science . As a science,the amount of illumination required and certain aspects of the quality of light have been quantified.  As an art  light is an experience of senses,it is not an intellectual experience. Lighting should create an atmosphere pleasing to the occupants whether in an office,store,restaurant or home. Lighting should provide visibility ,character,and mood as well as relate harmoniously to the space in which it is used. EFFECT ON ARCHITECTURE Light defines space,reveals texture and color,shows form, indicates scale,separates functions.Lighting is dynamic. EFFECT ON INTERIOR DESIGN Light is invisible until it strikes a surface and  molds our environment. The angle and quality of light ,along with intensity determines how we perceive space,its occupants and its furnishings. There is a vital relationship between Light and color PLANES OF BRIGHTNESS Brightness in space establishes the character or feeling of t...

Fundamentals of Glare

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Glare In simplistic terms, glare is any light source either direct or reflected that reduces short term or long term visual performance. It is the equivalent of noise in an audio system. Glare results from an extremely complex set of interactions between the lighting, both electric and natural, the surroundings and the visual system of the body. Although there is a general understanding of the mechanism of glare and some algorithms for prediction of glare, the prediction of the models often, do not agree with the perception of the occupants. The fact that glare cannot be reliably calculated does not diminish its detrimental effect on the visual environment, nor its need to be addressed in the design process. At the same time it is not sufficient in designing a lighting installation to say that, as glare is bad, we should minimise it as much as possible. There have been many disastrous installations predicated on this philosophy. Many attempts to eliminate glare have resulted ...

Lighting Theory

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 LIGHTING THEORY Lighting can be considered in 4 stages, source, flow, illuminance and luminance. 1. SOURCE - the light source has a  luminous intensity (symbol I ) and is measured in candela . 2. FLOW - the flow of light, or light flux ( symbol φ) which is measured in lumens. 3. ILLUMINANCE (symbol E ) - when light falls on a surface, the level of illumination on that surface is referred to as illuminance. The unit of measurement is lux . (lumens per square metre) 4. LUMINANCE (symbol L ) – The fourth stage of this process is the light  leaving the surface which has been illuminated by the source. Consider a situation where the same amount of light strikes both a “dark” surface  and a ”bright” surface. The illuminance is the same in each case but due to the  greater reflectance of the “bright” surface it now becomes a secondary source of  light. Its luminance will therefore be much greater than that of the dark surface.  Luminan...