Advanced Electrical Services Chapter 3 : Extra Low Voltage System 1 VTC 2013
Learning outcome Analyses and develop solutions for problems in the extra low voltage system and identify their applications Learning contents Security system: CCTV system, Access control, and watchman tour Building management system
ELV Systems Different types of ELV systems Building Management System (BMS) Heating, Ventilation and Air-conditioning System (HVAC) Fire Services System Communal Aerial Broadcast Distribution (CABD) / Cable TV (CATV) / Satellite Master Antenna Television (SMATV) System
ELV Systems Security systems Closed Circuit Television Surveillance, CCTV Access Control Watchman Tour Door Monitoring Communication Systems Door Phone Public Address Nurse call Car Park Management System
Building Management System An integrated control system for the facilities within a building or group of buildings Functions To control and monitor facilities in buildings To ensure energy saving and efficiency To provide tenant comfort, security and safety To enable and facilitate effective building management
Building Management System
Building Management System Trend of development Intelligent building automation Johnson Control Honeywell Echolon LonWorks BACnet Remote control of equipment through internet or web Heavy initial installation cost Long term benefits to tenants and landlord
Building Management System BACnet
Building Management System Lonworks Operator Interface IP/Ethernet LAN IP Router Device Network
Heating Ventilation & AC A control system for the control of environmental temperature, humidity, air circulation, and air quality within a building
Heating Ventilation & AC
Heating Ventilation & AC
Fire Services A control and warning system for the tasks of detection, warning alarm, monitoring and fire fighting Common equipment used in fire services Smoke detector, heat detector Sprinkler system Fire hydrant/hose reel systems Automatic Fire Alarm System
Fire Services Smoke detector Sprinkler
Fire Services Fire Alarm Panel Manual call point
CABD/CATV/SMATV A wiring system for the transmission of audio and video signals from signal generation stations or cameras to a connection outlet in each unit of a building The system is to serve all the residents in a building with the connection outlets for getting the services of audio (radio), video (TV and CCTV) and digital signals (broadband) Group of frequencies assigned to a broadcast station for transmission of their signal is called a channel A number of channels are grouped together called a band
CABD/CATV/SMATV Each channel has a separation of 8 MHz between one another in Hong Kong Television broadcasting stations in Hong Kong are using UHF Bands IV and V CABD system composes of two major sections Headend Distribution network
CABD/CATV/SMATV
CABD/CATV/SMATV Headend is the master of CABD system. It should include but not all of the following equipments Antenna Antenna amplifier (if any)- to boost the input antenna signal Splitter- for splitting the input antenna signals into a number of inputs to individual single channel amplifier
CABD/CATV/SMATV Bandpass filter or coupler- a bandpass filter is being used to transit the desired channel into the specific single channel amplifier with a maximum rejection to other channels. A coupler is a high isolation and selectivity splitter Single channel amplifier- usually termed as channel amplifier. It gives amplification only to the specific band and normally incorporate a gain control device to adjust the output level Combiner-combines signal frequencies output of two or more signal transmitters into a signal output
CABD/CATV/SMATV Satellite Antenna
CABD/CATV/SMATV TV Aerial
CABD/CATV/SMATV Frequency Bands Designation Abbreviation Frequency range Low frequency LF 30 khz - 300kHz Medium frequency MF 300kHz 3MHz High frequency HF 3MHz - 30MHz Very high frequency VHF 30MHz 300MHz Ultra high frequency UHF 300MHz 3GHz Super HF (Microwave range) SHF 3GHz - 30GHz
CABD/CATV/SMATV Broadcasting Services and Sub-division of Frequencies Range Band Channel Frequency Service LF - - 150-285 khz AM sound long wave MF - - 535-1605 khz AM sound medium wave HF - - 2.3-26.1 MHz AM sound short wave VHF I 1-5 41-68 MHz TV Band I II - 88-108 MHz FM sound (VHF) III 6-13 175-215 MHz TV band III CATV 230 400 MHz Band for cable TV UHF IV 21-34 470-582 MHz TV band IV V 39-68 614-854 MHz TV band V
CABD/CATV/SMATV Combiner TV Amplifier Splitter
CABD/CATV/SMATV Distribution Network Distribution amplifier- to compensate the distribution loss or cable loss in the network Splitter- a passive component supplying signals to a number of outputs which are individually matched and suitably isolated from each other Outlet- a socket to supply both TV/FM signals to subscriber s receiver
CABD/CATV/SMATV Transmission Line Twin Lead The line is unshielded hence subject to radio interference It is relatively cheap and flexible for ease of handling 300 Ω characteristic impedance.
CABD/CATV/SMATV Coaxial line All the audio and video signals are at very high frequencies (from 30 khz to 300 MHz), the signals are susceptible to attenuation and noise interference Coaxial cables are used all the way from the antenna to the monitors in order to minimize the attenuation and increase the immunization of noises 75 Ω characteristic impedance.
CABD/CATV/SMATV Coaxial Cable Wideband Modulator
CABD/CATV/SMATV Example: Calculate CABD signal strength in dbµv delivered to each TV set. Antenna Signal 46 db Cable loss -6 db To TV set Cable loss -6 db Splitter loss -3 db to each output Pre-amp Gain 17 db To TV set Cable loss -6 db
CABD/CATV/SMATV Antenna signal level Preamp gain Signal strength at preamp o/p Cable loss to splitter Signal strength to splitter i/p Splitter loss to each o/p Signal strength at splitter o/p Cable loss, splitter to TV Signal level to TV set 46dBµV +17dBµV 63dBµV - 6dBµV 57dBµV -3dBµV 54dBµV - 6dBµV 48dBµV
CABD/CATV/SMATV The signal strength shown in the above example is far below the requirement. According to the requirement of TV signal shall fall within 60dBµV for all Band IV channels and 63 to 80dBµV for Band V channels. The difference between the strongest and the weakest TV signal from the TV socket outlet shall not exceed 6dBµV. Distribution amplifier shall be added to compensate the signal losses.
Cable TV The major carrier of Cable TV signals is through optic fiber cables from the station to buildings The signal is demodulated and modulated inside the buildings and transmitted through coaxial cables to the users At some remote sites, microwave transmission through dish antenna is also done in order to save the installation cost of cables The residents, who wish to get the service of Cable TV need to subscript for the services; a decoder box is installed at each unit to provide the Cable TV signal
SMATV Antenna-gain is directly proportional to the size of the area which intercepts microwaves Receiver-receives the transmitted signals and decodes the message Down converter- amplify and convert high frequency signals to a much lower frequency. These lower frequencies travel through cables with much less attenuation of the signal, also much easier and cheaper to design electronic circuits to operate at these lower frequencies Audio/video modulator-converter signals into in-home channels for viewing on every TV in house
Digital Terrestrial TV Broadcasting Adopt China s DTTB standard Develop by TsingHwa University and ShangHai Jiao Tong University Advantages Same coverage with lower transmission cost-less power Improve reception TV signals and anti-interference ability Maximum channel efficiency Mobile and indoor reception
Digital Terrestrial TV Broadcasting Frequency Selection
Digital Terrestrial TV Broadcasting Schematic same as conventional CABD system except DTT antenna DTT channel amplifier Digital TV receiver Digital TV monitor DTT antenna DTT channel amplifier
Digital Terrestrial TV Broadcasting Digital TV receiver Able to decode / process and display digital TV broadcasts Have an internal tuner circuit allowing to receive and display in standard or high-definition format Digital TV monitor Have built-in tuner or require set-top box Capable to display standard or high-definition images as required by digital TV standards
CCTV System It is used for getting a video signal from a CCTV camera or door phone onto a CABD system The audio and video signal is connected to the wide band modulator via or distribution system Remote eyes for a security operator by providing live action displays from a distance Maintain permanent records for future training or as evidence in prosecution
CCTV System
CCTV System CCTV System Camera Outdoor and indoor type Fixed, pan, tilt and zoom type View image in extreme low-light condition, e.g. 0.05lux Controller Control the camera for different viewing angles and pan/tilt/ zoom Many cameras can be controlled by a single controller Monitor View live camera pictures and playback
CCTV System Multiplexer Capable to monitor up to 16 CCTV cameras simultaneously on one screen Display full screen, 4, 9 and 16 split multi-screen on a monitor without affecting the recording operation Capture up to 16 camera pictures and output to the time lapse video cassette recorder or digital video recorder Time Lapse Video Cassette Recorder, VCR For recording or instant viewing Record on a standard 3 hours type for 24 hours Digital Video Recorder Real-time live video monitoring from all 16 cameras Playback during recoding
Access Control System Manage the flow of people and record the access information Right people gain access to the restricted premises Ability to track employees throughout the facility Innovative technology Smart Card Contain an integrated circuit chip embedded in the plastic of the card Record and store information and personal identification codes in the memory
Access Control System Fingerprints Person s fingerprint from one finger is collected and stored by the system An electro-optical recognition technique to establish a positive comparison from stored data before permitting access Face Recognition Face recognition using 3D imaging technology determines a good match between an enrolled face image and a live face image captured at the access terminal
Access Control System Iris Recognition The iris pattern is processed and encoded into a record Live iris is presented for comparison with the stored pattern
Access Control System Functions of equipment Access reader Check and compare the access code with the stored pattern Access controller Open the door once received signal Relock the door after the pre-set period Registration Unit Data input terminal Registration / Database Computer Store and recall information for further comparison with the access code Record the entry / exit data for statistical analysis or other applications
Watchman Tour System Record the time, data and security officer ID during the security officer patrols the building The system can be computerized and programmable with different tour routes Check point Devices / Reader Key switch / key RFID check point / inductive reader
Watchman Tour System RFID check point and inductive reader
Watchman Tour System
Door Monitoring System Door monitoring system composes Magnetic door contact Alarm buzzer completed with indicating light Alarm signal to security control room displays on a mimic panel or monitor Door monitor control unit Provide at exit doors leading to external areas to prevent unauthorized entry Opening of exit door shall cause the local alarm to sound and an alarm signal shall be sent to security control room to report the alarm Status of exit door ( i.e. open / close) show on the mimic panel / monitor
Door Monitoring System
Door Phone System A door phone system is to provide intercom services between two or more different locations Usually outdoor to indoor communication Indoor to indoor communication Multi-core cables are used for the transmission of signals
Door Phone System Door Phone System
Door Phone System Two to Two Circuit
Door Phone System Outdoor Unit Indoor Unit
Door Phone System Wiring of a typical domestic door phone system
Door Phone System Multi-core cable for door phone system
Public Address System Public Address System uses for making announcement and playing background music, to the selected areas of a building, it composes Speaker Zone speaker selector Microphone AM/FM radio tuner DVD player Volume control
Public Address System
Nurse Call System Summon help through this emergency call system for Elder persons Persons with physical impairments Handicaps Patient in hospital
Operation Call from 2 way pendant When the patient is not in bed, and has emergency who presses the button of pendant to summon help The signal will be transmitted through the central receivers to the computer center Immediately, the computer center will page the nurse to take care of the patient and at the same time inform the patient a nurse is coming Nurse ID When the nurse receives the instruction from the computer center to go to the patient for checking The nurse can press the Nurse ID button to cancel the emergency call and at the same time her ID will be transmitted to the control center and be recorded in the computer system
Operation Call from room station External button is installed on the patient s bed in the hospital When patient presses the external button, the room station will sent out the signal to computer center to summon help Immediately, the computer center will page the nurse to take care of the patient and at the same time inform the patient a nurse is coming
Car Park Management System
Car Park Management System Control and handle the Hourly parking Season / monthly parking Parking for user shopping Monitor and record the status of parking spaces Facilitate the cost and car park management Reduce the levels of crime within the car park
Car Park Management System System composes Entrance control unit Exit control unit Central data station and cashier computer unit CCTV system Intercommunication system
Entrance Control Unit Floor mounted combined ticket dispenser / ticket reader Intercom facilities in connection with the master system at cashier office Floor mounted automatic drop gate Underground presence and passage loop detectors CCTV camera FULL sign The vehicle entering and leaving the car park will be counted in order to determine when it is full
Entrance Control Unit When the vehicle stops at the ticket dispenser / ticket reader, its presence is detected by the detection loop and the ticket dispenser / ticket is set to issue / receive a ticket For season / monthly parking, if the ticket is detected to be valid, the ticket will be reprogrammed for exiting purpose The barrier will raise and then will close automatically after the vehicle has passed the closing detection loop
Exit Control Unit Floor mounted ticket reader Intercom facilities in connection with the master station at cashier office Floor mounted automatic drop gate Underground presence and passage loop detectors CCTV camera
Exit Control Unit When the vehicle stops at the ticket reader, its presence is detected by the presence detection loop and the reader is set to receive the ticket If the ticket is valid, the barrier will raise and lower after the vehicle has passed the closing detection loop
Central Data Station / Cashier Computer Unit Ticket reading and encoding terminal produces the monthly tickets and calculating hourly parking fee Record of malfunctions of equipment and every transaction Daily accounting record and statistics Information on parking spaces Instant cash audit Instant ticket checking
Central Data Station / Cashier Computer Unit Independent control of the barriers Activation of the external FULL sign Automatic printout and alarm message in case of fault operation Operation of central data station controls by pre-determined data access code by different operating level, i.e. cashier, supervisor and manager
CCTV System The traffic condition at the entrance and exit points of the car park can be monitored through the CCTV monitors and can be recorded by the time lapse VCR