Wednesday, April 26, 2017

CCTV installation challenges

CCTV installation challenges

We describe some of the challenges you can encounter during installation, and how to deal with them. We’ll guide you through areas such as cabling, network setup, environmental considerations, and camera selection and placement.
Considerations when cabling
Use the correct wiring standards
There are two wiring standards for network cabling: T568a and T568b. DO NOT COMBINE T568a and T568b on the same cable.

Use high-quality CAT 5e or CAT 6 cabling
Cables are categorized according to the data rates that they can transmit effectively. The specifications also describe the material, the connectors and the number of times each pair is twisted per meter. The most widely-installed category is CAT 5e. Ensure that the cabling in your installation fulfills the required Category (Cat).

Cat 3 (no longer used) with 16 MHz bandwidth
Cat 5e with 100 MHz bandwidth
Cat 6 up to 250 MHz
Cat 6A up to 500 MHz
Cat 7 up to 600 MHZ
Cat 7A with a frequency range through 1000 MHz

Video files are generally very large data files, and need to be moved around the network as quickly as possible. In general, it is possible to use good-quality Cat 5 cabling for gigabit networks; it is recommended to utilize Cat 5e or Cat 6 cabling for gigabit connectivity, even if your existing network switches and routers support only 100 Mbps. This will ensure that the cabling infrastructure is in place when the gigabit upgrade occurs. The rest of the points apply equally to 1 Gbps and 100 Mbps connections – each can be affected by poor cabling and incorrect connections.


Have good cable runs
Ensure that your cabling meets the requirements of your equipment. The distance between a transmitter and a receiver cannot be greater than 100 m (325 ft) in total. If installing sockets, remember to take into account the distance between the socket and the computer. A good rule of thumb is 90 meters for horizontal runs, and ten meters for the patch cabling. It is also important to be aware that the whole length of cable and connectors is of the same type, such as STP.
Do NOT run cabling next to electrical mains cabling (because of the potential for interference), or suspend network cabling from ceiling tiles (this may violate building codes and fire regulations).

Axis network products are intended to be used with Shielded Twisted Pair (STP) cables in Europe due to CE-marking requirements and are EMC approved with STP cables. This requirement is also valid for several other countries such as Australia/New Zealand, Canada, Korea and Japan. The use of STP cables is especially important to maintain a high degree of immunity to RF (Radio Frequency), electrical and magnetic disturbances as well as provide the lowest possible degree of radiated and conducted Radio Frequency emission.
It is also mandatory to use an STP cable where the camera is used outdoors, or where the network cable is routed outdoors. STP cables also lower the effects of close situated power relays, motor inverters and electrical cables that are run in parallel close to network cables. Shielded Twisted Pair (STP) cabling needs to be grounded. This is normally accomplished since the switch or POE adapter is connected to an earthed mains socket. For more information about STP versus UTP, go to Shielded or unshielded network cables.
The electrical environment shall be considered when deciding which type of Twisted Pair cable is to be used.
Since network cabling typically uses solid wire, cabling should not be twisted or bent into a tight radius (not less than 4 times the diameter of the cable). Do not use metal staples to secure cable runs, nor tightly adjusted cable wraps. Avoid a daisy chain network topology.
Use the correct connectors
Network connections use RJ45 connectors designed for either stranded or solid cable, but usually not both. Ensure that you use the correct crimping tool for the specific type of connector.

The customer can use the connector being shipped, or decide to order an optional premounted cable with the connector already attached, called the RJ-45 IP66-rated Cable with premounted connector (CAT6) 5 m. This connector maintains the the IP66 rating of the camera and prevents dust and moisture from entering into the dome assembly.
Ethernet cables can be run outdoors, but their thin plastic casing will deteriorate quickly when exposed to the elements. For best results, outdoor Ethernet cables should be placed in a conduit and buried a fair distance away from power lines or other sources of electrical interference. Remember to use an STP cable if the camera is used outdoors or if the network cable is routed outdoors.
PVC or other plastic pipe, installed with waterproofing, can work as a conduit. Special exterior or direct burial CATEGORY cables could be used for outdoor runs. Direct burial CAT5 cable costs more, but it is designed specifically for outdoor use. Both ordinary and direct burial CAT5 cables attract lighting strikes to some degree. Simply burying a cable underground does not lessen its affinity for lightning. Accordingly, CAT5 surge protectors should be installed as part of outdoor Ethernet networks to guard against lightning strikes.

Keep the pairs together and wire correctly
A network cable consists of four pairs of twisted wires, and these are color coded (orange, green, blue and brown). The cable specification has been designed for high-speed data transfer and very little cross-talk. It is very important that no more than about 6 mm of the cable is untwisted at either end; otherwise, problems such as ‘near end cross-talk’ can arise, which will have a detrimental impact on your network. It is essential that you wire the plug correctly and not just from pins 1 through 8 at both ends.
Environmental conditions
Environmental considerations, for example whether the camera will be installed indoors or outdoors, determine the cabling and connectors to use.
Depending on the environment, the camera should be installed with the adequate housing to provide the correct level of protection. If the camera is exposed to acids, severe weather conditions, or extreme heat or cold, the camera needs a housing that withstands this kind of environment. For more information on Environmental issues, see Challenge 5, Environmental Considerations.
Certify the installation
In twisted-pair copper wire networks, copper cable certification is achieved through a thorough series of tests in accordance with standards set by the Telecommunications Industry Association (TIA) or the International Organization for Standardization (ISO). These tests are done using a certification testing tool, which provide "Pass" or "Fail" information.

Voltage transients
The most recognized cause of transient voltage is lightning; however, the most frequent source is the local power grid.
Network camera for outdoor installation are protected by design against power surges and transients. Part of this design involves using a shielded network cable STP between the PSE (Power Sourcing Equipment - The term PSE defines any device connected at the camera end of the cable, such as a midspan, endspan, network switch, network hub or power injector.) and the camera to ensure a path for the power surge to reach ground.
The installation of cameras using a shielded cable STP and a properly grounded PSE has been tested to comply with industry immunity standards levels, for example for surge protection. Any other installation method will void the warranty and leave the unit at risk.
Always use a shielded network cable STP between the camera and the PSE, and ensure that the PSE is properly grounded.
Calculating the total power needed
Power over Ethernet (PoE) is a mechanism for supplying power to network devices over the same cabling used to carry network traffic.

There are currently two standards for PoE: 802.3af allows for a maximum of 15.4 W per channel, whereas PoE 802.3at doubles the available power to 25 W.
The total power consumption requirement of all equipment that will be connected to a specific switch on a network needs to be calculated to ensure sufficient power is available per switch. This total wattage requirement must be less than a switch’s PoE power budget – total PoE power per switch and per port.
The following chart shows the power consumption at both the PSE and the PD.
Class
Usage
Power Level Output at the Power Sourcing Equipment (PSE)
Maximum Power Levels at the Powered Device (PD)
0
Default
15.4 W
0.44 - 12.95 W
1
Optional
4.0 W
0.44 - 3.84 W
2
Optional
7.0 W
3.84 - 6.49 W
3
Optional
15.4 W
6.49 - 12.95 W
4
Valid for 802.3at High PoE
30 W
12.95 - 25.5 W
 Example of power requirements in a PoE system


As illustrated in above Figure, six cameras, all PoE Class 2, are connected to one switch. Since a Class 2 device draws 7 W maximum from the switch, we can calculate the power requirements for a total of 6 cameras X 7 W = 42 W.

This will be the PoE power budget. Therefore, we need a switch with at least 42 W available for PoE.

Examples of  xPoE and powering calculation with Axis cameras

The examples present the concept behind the PoE and powering calculation for an Axis camera. The exact figures and products used in the examples may change over time.


High PoE with AXIS Q6032-E

The AXIS Q6032-E power input is specified in the datasheet as max. 60 W and in the Installation Guide (IG) it is specified as 50 W (max.). However, the midspan AXIS T8124 input is specified as max. 74 W.
Why is the input 50 W/60 W for the camera, but 74 W for the midspan?
The background for this is that the midspan itself consumes power and there is loss of power in the RJ45 cable from the midspan to the camera. Therefore, to ensure proper power to the camera, the midspan needs input and output power that is higher than the camera needs.
To conclude: input to the midspan is 74 W, and output from the midspan is 60 W, while input to the camera is 50 W.

PoE with P13xx-E

Some cameras are specified with two different classes of PoE. This is because products can require different wattages, depending on whether they are used with or without extra equipment, such as heating or cooling. The first PoE number specifies the wattage for the product itself, whereas the second number specifies the wattage needed for the product, including extra equipment. The AXIS P13xx-E is an enclosed product, and is specified as "PoE IEEE 802.3af max. 12.95 W or High PoE max 25.5 W".

Using Direct Current (DC) Midspan

DC may be used for certain applications, such as solar panels, and AXIS has the T81B22 30W DC midspan for just this purpose. T81B22 is specified as “51 V DC at: 12 DC IN (max. 30 W) or 24 V DC IN (max. 15 W)”.


PoE switch with P3384-VE

AXIS P3384-VE is specified as "Power over Ethernet IEEE 802.3af Class 3; max 12.1 W".

How can you find out what switch to use?
Usually the provider of the PoE switch describes three parameters that should be taken into account when deciding upon what switch to use. For example, the three parameters could be as follows:
·        Supplies power to PD: up to 15,4 W
This value is the maximum PoE power the switch can deliver per port, and is not related to total PoE budget. It is important to remember that it says "up to".
·        Total PoE budget:
The total PoE budget is what the switch can deliver in total PoE power on all ports. High value and few ports means a higher value of W per port. Low value and many ports mean a lower value of W per port.
·        Average PoE W / port: 13
Example: 50 W is the total PoE and the switch has 4 ports => 52 W / 4 = 13 W
This value is basically what the switch per port can handle if all PoE ports are being used. It is important to have a margin here to be on the safe side to know my device.
Basically, in this example, an 802.3af PoE switch would be suitable for the camera, and can be used to connect four AXIS P3384-VE’s.

Ensure the right PoE for environmental conditions

The PoE powering of a device becomes more critical depending on temperature. Many devices can function at different low temperature levels based on the amount of power available. It is imperative to verify the correct midspan is used for exterior cameras. AXIS P1344-E can operate down to -40°C when using high PoE.

Environmental
Surveillance cameras are often placed in environments that are very demanding. Failure to adequately protect an installed device from environmental factors can cause premature failure or void the product warranty.

Select the correct housing based on conditions

Camera housings come in various sizes and qualities, and various features. Housings are made of either metal or plastic and can be classified into two general types: fixed camera housings and dome camera housings.
When selecting an enclosure, several things need to be considered, including:
·        Side or slide opening (for fixed camera housings)
·        Mounting accessories
·        Clear or smoked dome (for dome camera housings)
·        Cable management
·        Temperature and other ratings (consider the need for a heater, sunshield, fan and wipers)
·        Power supply (12 V, 24 V, 110 V, etc.)
·        Level of vandal resistance

Ingress Protection Rating (IP Rating)

The IP Code classifies and rates the degrees of protection provided against the intrusion of solid objects (including body parts like hands and fingers), dust, accidental contact, and water in mechanical casings.

Solid particle protection

The first digit indicates the level of protection that the enclosure provides against access to hazardous parts (for example, electrical conductors, moving parts) and the ingress of solid foreign objects.
Level
Object size protected against
Effective against
0
-
No protection against contact and ingress of objects
1
>50 mm
Any large surface of the body, such as the back of a hand, but no protection against deliberate contact with a body part
2
>12.5 mm
Fingers or similar objects
3
>2.5 mm
Tools, thick wires, etc.
4
>1 mm
Most wires, screws, etc.
5
Dust protected
Ingress of dust is not entirely prevented, but it must not enter in sufficient quantity to interfere with the satisfactory operation of the equipment; complete protection against contact
6
Dust tight
No ingress of dust; complete protection against contact



Liquid ingress protection

Level
Protected against
Testing for
Details
0
Not protected
-
-
1
Dripping water
Dripping water (vertically falling drops) shall have no harmful effect.
Test duration: 10 minutes
Water equivalent to 1mm rainfall per minute
2
Dripping water when tilted up to 15°
Vertically dripping water shall have no harmful effect when the enclosure is tilted at an angle up to 15° from its normal position.
Test duration: 10 minutes
Water equivalent to 3mm rainfall per minute
3
Spraying water
Water falling as a spray at any angle up to 60° from the vertical shall have no harmful effect.
Test duration: 5 minutes
Water volume: 0.7 liters per minute
Pressure: 80–100 kPa
4
Splashing water
Water splashing against the enclosure from any direction shall have no harmful effect.
Test duration: 5 minutes
Water volume: 10 liters per minute
Pressure: 80–100 kPa
5
Water jets
Water projected by a nozzle (6.3mm) against enclosure from any direction shall have no harmful effects.
Test duration: at least 3 minutes
Water volume: 12.5 liters per minute
Pressure: 30 kPa at distance of 3m
6
Powerful water jets
Water projected in powerful jets (12.5mm nozzle) against the enclosure from any direction shall have no harmful effects.
Test duration: at least 3 minutes
Water volume: 100 liters per minute
Pressure: 100 kPa at distance of 3m
7
Immersion up to 1m
Ingress of water in harmful quantity shall not be possible when the enclosure is immersed in water under defined conditions of pressure and time (up to 1 m of submersion).
Test duration: 30 minutes
Immersion at depth of 1m
8
Immersion beyond 1 m
The equipment is suitable for continuous immersion in water under conditions which shall be specified by the manufacturer. Normally, this will mean that the equipment is hermetically sealed. However, with certain types of equipment, it can mean that water can enter but only in such a manner that it produces no harmful effects.
Test duration: continuous immersion in water
Depth specified by manufacturer

Determining the coverage area
When selecting cameras, the field of view required should be defined. The field of view is determined by the focal length of the lens and the size of the image sensor; both are specified in a network camera’s datasheet.
A lens’ focal length is defined as the distance between the entrance lens (or a specific point in a complicated lens assembly) and the point where all the light rays converge to a point (normally the camera’s image sensor). The longer the focal length of the lens, the narrower the field of view (FoV) will be.
The FoV can be classified into three types:
·        Normal view: offering the same field of view as the human eye.
·        Telephoto: a narrower field of view, providing, in general, finer details than a human eye can deliver. A telephoto lens is used when the surveillance object is either small or located far away from the camera. A telephoto lens generally has less light gathering capability than a normal lens.
·        Wide angle: a larger field of view with less detail than in normal view. A wide-angle lens generally provides good depth of field and fair, low-light performance. Wide-angle lenses sometimes produce geometrical distortions such as the "fish-eye" effect.
It is always advisable to take a snapshot from the camera to verify the coverage is correct and the depth of field is sufficient to capture the requirements. As depth of field changes with the available lighting, make certain to verify this multiple times per day.

Camera placement
When determining camera placement during installation, many factors must be taken into account. As mentioned in Camera Selection, the surveillance objectives decide what type of camera should be used, as well as how the camera should be placed.
Acquiring a useful image involves much more than simply pointing the camera at an object. Lighting, angle, reflections, dead zones, and the zoom factor for PTZ cameras are things to consider. Avoiding backlight and minimizing reflections are other factors that should be addressed. In some environments, in order to solve challenging scene problems, it’s easier to change the environment itself.
Camera placement is also an important factor in deterring vandalism. By placing a camera out of reach on high walls or in the ceiling, many spur-of-the-moment attacks can be prevented. The downside may be the angle of view, which can be compensated for to some extent by selecting a different lens.
The purpose of each camera should be clearly specified. If the aim is to get an overview of an area to be able to track the movement of people or objects, make sure that a camera suitable for the task is placed in a position that achieves the objective.
If the intention is to be able to identify a person or object, the camera must be positioned or focused in a way that will capture the level of detail needed for identification purposes. Local police authorities may also be able to provide guidelines on how best to position a camera.

Light considerations
For successful camera placement, light considerations are crucial. It is normally easy and cost-effective to add bright lamps in both indoor and outdoor situations to provide the necessary light conditions for capturing good images.
When mounting cameras outdoors, it is important to consider how the sunlight will change during the day. It is also important to avoid direct sunlight, as it will “blind” the camera and can reduce the performance of the image sensor. If possible, position the camera with the sun shining from behind the camera.
Camera angles

Detection zones and dead zones

The different ranges/zones of a camera are depicted in Figure XX. The line closest to the camera is where the maximum height is detectable. The yellow line illustrates the minimum required detectable height. The detection zone is in between these lines. These factors need to be addressed at the time of installation to ensure proper camera coverage.

Considerations during installation
For a successful installation, ensure the following:
·        The installer must ensure that he/she reads the included installation documentation.
·        The proper screwdriver, Allen wrench, etc. should be used, so as not to damage the mounting hardware.
·        The correct security tool should be used for vandal-resistant dome assemblies.
·        Ensure that all transport and packaging materials are removed from the dome assembly. This is very important especially for PTZ cameras, which is often packaged with a foam insert to protect the camera during transport.
Documentation
When performing a camera installation, make sure to document the installation properly.
This is not done for its own sake; there are many reasons for it. First of all, it is crucial for the user when it comes to future installations. Furthermore, it is a matter of security for the user to know vital safety and planning information, such as how the cables are wired. Proper documentation can also help to reduce customer calls.
All aspects of the physical installation should be documented during the actual installation process. This documentation should include, but not be limited, to the following:
·        Physical network layout showing all cable locations and the cable and port numbering scheme
·        Camera and server IP addresses
·        As-built floor plan showing camera locations
·        Camera parameter setup list
The documentation required by the end user can then be handed over at the proper time, allowing for the end user to verify the information and also make better use of the training provided prior to system startup.

End user training
End user training is one of the most important final tasks for the completion of an installation.
This step is required, not only to introduce users to new equipment but also to consolidate new processes and procedures which may have been introduced by the installation.
Training not only benefits the user, it benefits the integrator by reducing post-installation questions. It also allows end users to make much better decisions and use of the installed system.

The end user training will require documentation from the equipment manufacturer as well as integration technicians. All aspects of the system will need to be taught to the users. Various user groups might also require different training levels, from simple PTZ camera control and configuration to VMS recording and playback.

This Artical publish in safe secure magazine April 2017.

Saturday, April 15, 2017

CCTV in Hill Area

ভোটের আগে অশান্তি এড়াতে সিসিটিভি বসছে শৈল শহরে

বর্তমান সময়ে অফিস, ব্যবসা প্রতিষ্ঠান এবং বাসা-বাড়ির নিরাপত্তা নিয়ে সবাই চিন্তিত! এসবের নিরাপত্তার জন্য আমরা অনেক কিছুই করি। কিন্তু কোন কিছুতেই যেন বিশ্বাস হয় না। আসলেই আপনি কাকে বিশ্বাস করবেন? সিকিউরিটি গার্ড? ড্রাইভার? কাজের লোক? আত্বীয়স্বজন? কারও উপরই আজকাল ভরসা নেই। তাই তথ্যপ্রযুক্তির এই যুগে ভরসা রাখতে পারেন বিশ্বস্ত সিকিউরিটি যন্ত্রপাতির উপর। কারণ এরা কখনই আপনার সঙ্গে বিশ্বাসঘাতকতা করবে না কিংবা ডিউটির কথা বলে ঘুমিয়েও থাকবে না।
“নিরাপত্তা” এমন একটি গুরুত্বপূর্ণ শব্দ যা আমাদের প্রতিদিন প্রতিটি মুহুর্তেই প্রয়োজন। বর্তমান প্রেক্ষাপট আর  যুগের সাথে পরিবর্তনের অঙ্গিকারে প্রযুক্তির উপহারে আরো উন্নত এবং নিখুত হয়েছে নিরাপত্তা ব্যবস্থা। আর নিরাপত্তা বাবস্থাকে আরো এক ধাপ নিশ্চিত করে নানান ধরণের সিসিটিভি ক্যামেরা। বর্তমান চাহিদা অনুযায়ী দুই ধরনের রঙ্গীন সিসিটিভি মনিটরিং সিষ্টেম বাজারে পাওয়া যাচ্ছে। ষ্ট্যান্ড এ্যালোন এমবেডেড ডিভিআর (ডিজিটাল ভিডিও রেকর্ডার) সম্বলিত সিসিটিভি মনিটরিং সিষ্টেম এবং পিসি বেজড সিসিটিভি মনিটরিং সিষ্টেম। 
সিসিটিভি ক্যামেরা সিষ্টেম এর ব্যবহার আমাদের দেশে দুই-তিন দশক আগে থেকে মোটামোটিভাবে শুরু হলেও পশ্চিমা দেশগুলোতে আরো বহু আগে থেকেই ব্যবহৃত হয়ে আসছে। যদিও সিসিটিভি ক্যামেরা সিষ্টেম তখন ছিল শুধু সাদা-কালো, এসব ক্যামেরায় অল্প আলোতেই পরিষ্কার ছবি দেখা যেত। পরবর্তিতে রঙ্গীন ক্যামেরা বাজারে আসলেও স্বচ্ছ ছবির জন্য প্রচুর আলোর প্রয়োজনীয়তার কারনে ব্যবহার সীমিত হয়ে পড়ে। বর্তমানে প্রযুক্তিগত উন্নয়নের ফলে অনেক কম আলোতেই রঙ্গীন ক্যামেরায় পরিষ্কার ছবি দেখতে পাওয়া যায়। ফলে এখন আর সাদা-কালো সিসিটিভি ক্যামেরা বা সিষ্টেম উৎপাদন হচ্ছেনা।
দার্জিলিং শহরের বিভিন্ন রাস্তায় যান চলাচল নিয়ন্ত্রণ, অপরাধ দমনসহ জেলার বাংলাদেশ ও নেপাল সীমান্তবর্তী এলাকায় মাদক পাচার, নারী পাচারের মতো অপরাধ রুখতেই প্রশাসন সিসিটিভি ক্যামেরা বসানোর কাজ শুরু করল প্রশাসন৷ দার্জিলিংয়ে পুরসভা নির্বাচনের আগে কোনও অপ্রীতিকর পরিস্থিতি মোকাবিলায় শহরের বিভিন্ন রাস্তায় লাগানো এই সিসিটিভি ক্যামেরার মাধ্যমে জেলার পুলিশ নজরদারি চালাবে। গাড়ির চালকরা আইন ভেঙে গাড়ি চালালে তাদেরকেও এই ক্যামেরার মাধ্যমে মনিটরে আসা ছবি দেখে চিহ্নিত করা যাবে। ইতিমধ্যেই দার্জিলিং শহরসহ সমতলের শিলিগুড়ি মহকুমার ফাঁসিদেওয়া এবং খড়িবাড়ি ব্লকের বিভিন্ন জায়গায় জেলা প্রশাসন অতিরিক্ত নজরদারির জন্য ক্লোজড সার্কিট টেলিভিশন (সিসিটিভি) ক্যামেরা লাগানোর কাজ শুরু হয়েছে৷
বর্তমান চাহিদা অনুযায়ী দুই ধরনের রঙ্গীন সিসিটিভি মনিটরিং সিষ্টেম বাজারে পাওয়া যাচ্ছে। ষ্ট্যান্ড এ্যালোন এমবেডেড ডিভিআর (ডিজিটাল ভিডিও রেকর্ডার) সম্বলিত সিসিটিভি মনিটরিং সিষ্টেম এবং পিসি বেজড সিসিটিভি মনিটরিং সিষ্টেম। ব্যবহারের ভিন্নতার কারনে বর্তমানে রঙ্গীন সিসিটিভি ক্যামেরা বিভিন্ন প্রকারের হয়ে থাকে। যেমনঃ সাধারন ক্যামেরা, ডোম ক্যামেরা, হিডেন ক্যামেরা, স্পাই ক্যামেরা, স্পীড ডোম পিটিজেড ক্যামেরা, হিডেন ক্যামেরা, স্পাই ক্যামেরা, ডে-নাইট ক্যামেরা, জুম ক্যামেরা, ভেন্ডাল প্রুফ ক্যামেরা এবং আই পি ক্যামেরা উল্লেখযোগ্য। যারা একটু কম খরচে সিসিটিভি মনিটরিং বা রেকর্ডিং সিষ্টেম চান তাদের জন্য পিসি বেজড সিসিটিভি মনিটরিং এবং রেকর্ডিং সিষ্টেমই ভাল।
দার্জিলিংয়ে জেলা পুলিশের ট্রাফিক বিভাগের অফিস থেকে শহরের বিভিন্ন গুরুত্বপূর্ণ জায়গায় লাগানো সিসিটিভি ক্যামেরা এবং নজরদারির জন্য লাগানো মনিটরের উদ্বোধন করেন জেলার পুলিশ সুপার অমিত পি জাভালাগি। গোটা শহরে মোট ৪৮টি সিসিটিভি ক্যামেরা এখনও পর্যন্ত লাগানো হয়েছে। আধুনিক ক্যামেরাগুলির জুম করার যেমন ক্ষমতাও রয়েছে তেমনি এগুলি রাতেও পরিষ্কার ছবি সংগ্রহ করতে পারবে। এতে যেকোনও গাড়ির নম্বর অনায়াসেই ক্যামেরায় ধরা পড়ে যাবে। সমতলের শিলিগুড়ি মহকুমার খড়িবাড়ি, ফাঁসিদেওয়া ব্লকের বিভিন্ন জায়গাসহ ভারত-নেপাল সীমান্তের পানিট্যাঙ্কিতেও এই ক্যামেরা লাগানোর কাজ চলছে। পরবর্তী ধাপে কার্শিয়াংয়ে ক্যামেরা লাগানো হবে। ক্যামেরাগুলি ১৪ দিনের রেকর্ড সংরক্ষিত রাখতে পারবে।
দ্য প্রাইভেসি ইন্টারন্যাশনাল সিসিটিভি পেজে দেয়া তথ্যানুসারে, বর্তমানে সারা বিশ্বে আড়াই কোটিরও বেশি সিটিটিভি ক্যামেরা চালু রয়েছে। এ ছাড়াও শুধু যুক্তরাজ্যে প্রতিবছর সিসিটিভি ক্যামেরায় ৪৫ কোটি ডলার খরচ হয়। বাংলাদেশেও ব্যাপক ভাবে বেড়েছে সিসিটিভির ব্যবহার।
ক্যামেরা কেনার সময় আমাদের কিছু বিষয় অবশ্যই জেনে নেয়া দরকার যা আমরা অনেকেই জানি না-

  • এমন একটি ক্যামেরা কিনুন যাতে লাইভ ফিড, texting বা email এর features  থাকবে। এতে করে আপনি আপনার বাসায় কি হছে না হছে সব অফিসে বা যেকোনো জায়গায় থেকে দেখতে পারবেন।
  • Motion-sensor security ক্যামেরা অন্যান্য ক্যামেরা থেকে ভালো কাজ করে।
  • Night vision ক্যামেরাগুলো রাতের বেলা ভালো high-quality images ধারন করে।
  • আপনার বাসার সামনের এবং পিছনের দরজায় সিসিটিভি ক্যামেরা লাগান।
  • দাম একটু বেশি হলেও সবসময় একটি ভালো সিসিটিভি ক্যামেরা কেনার চেষ্টা করুন যাতে আপনি ভালো image quality পান।
জলপাইগুড়ি শহরের পিডাব্লুডি মোড়, রায়কত পাড়ার দিক থেকে দিনবাজার ব্রীজে ওঠার মোড়ে, নেতাজীপাড়া বাস স্ট্যান্ডের মোড় এবং শহরের প্রাণ কেন্দ্র কদমতলা মোড়ে সিসি ক্যামেরা লাগানোর কাজে শুরু হয়েছে। সেই সঙ্গে শহরে প্রবেশ মুখ গোশালা মোড় এবং পাহাড়পুর মোড়েও এদিন সিসিটিভি ক্যামেরা লাগানোর কাজ শুরু হয়েছে।


কাজের বরাত পাওয়া বেসরকারি সংস্থার তরফে জানা গিয়েছে, ক্যামেরা লাগানোর জন্য প্রতিটি মোড়ে পাকাপাকি ভাবে লোহার খুঁটি পোতা হয়েছে। প্রতিটি ক্যামেরা অত্যাধুনিক তথ্যপ্রযুক্তি সম্পন্ন হাই রেজুলেশন ক্যামেরা। অন্ধকারেও খুব ভালো ছবি তুলতে সক্ষম এই ক্যামেরা। ৫০-৮০ মিটার পর্যন্ত স্পষ্ট ছবি তোলার কার্যক্ষমতা রয়েছে ক্যামেরাগুলোতে। রোদ, ঝড়, বৃষ্টিকে উপেক্ষা করে ভালো কাজ করবে এই ক্যামেরা। প্রতিটি ক্যামেরাতে দীর্ঘ সময়ের রেকর্ডিং ধরে রাখার মতো স্টোরেড রয়েছে।
এই বিষয়ে জেলা পুলিশ সুপার অভিতাভ মাইতি বলেন, জেলার ৩৯ টি এলাকায় মোট ৮৯টি ক্যামেরা লাগানো হবে। প্রথম পর্যায়ে ১৫টি গুরুত্বপূর্ণ স্থানে ৪১টি ক্যামেরা লাগানের কাজ শুরু হয়ে গিয়েছে। বাকি জায়গাগুলোতে ধাপে ধাপে ক্যামেরা লাগানোর কাজে হবে। রাজ্য ট্রাফিক দফতরের বরাদ্দকৃত অর্থে এই কাজ হচ্ছে বলে জানান জেলা পুলিশ সুপার।
প্রশাসনিক কর্তারা মনে করছেন, গুরুত্বপূর্ণ জায়গাগুলোতে সিসিটিভি ক্যামেরা লাগালে একদিকে যেমন চুরি, ছিনতাইয়ের মতো অসামাজিক কাজকর্ম কমবে। তেমনই অভিযুক্তদের দ্রুত চিহ্নিত করা যাবে৷
সম্প্রতি শহরে বেশ কয়েকটি বড় ধরনের চুরি, ছিনতাই এমনকি বাইক চুরির মতো ঘটনার পর অভিযুক্তদের ধরতে কালঘাম ছুটে গিয়েছে পুলিশের। সেই সঙ্গে শহরের বুকে দ্রুত গতিতে বাইক চালানোর ফলে মাঝে মধ্যেই ঘটছে দুর্ঘটনা। এতে পুলিশের ভূমিকা নিয়ে প্রশ্ন উঠতে শুরু করেছে৷
ওয়াকিবহাল মহলের মতে, একদিকে শহরবাসীর নিরাপত্তা অন্যদিকে নিজেদের সমালোচনার হাত থেকে বাঁচাতে গুরুত্বপূর্ণ স্থান এবং শহরে ঢোকার মুখে সিসিটিভি ক্যামেরা লাগানোর সিদ্ধান্ত নিয়েছে প্রশাসন৷ তবে এই উদ্যেগ পুলিশের একার নয়৷জলপাইগুড়ি পুরসভা ও পুলিশ যৌথভাবে এই উদ্যোগ নিয়েছে৷
সম্প্রতি, পুরসভার চেয়ারম্যান মোহন বোস এবং জেলা পুলিশ সুপার অমিতাভ মাইতির মধ্যে বৈঠক হয়৷ সেই বৈঠকে উপস্থিত ছিলেন পুলিশের অন্যান্য আধিকারিকরা এবং সদর ট্রাফিক ওসি। বৈঠকে সিদ্ধান্ত হয়েছে, থানা মোড় এলাকায় এই সিসিটিভি ক্যামেরার কন্ট্রোল রুম করা হবে। তবে আপাতত প্রথম পর্যায়ের কাজে প্রতিটি ক্যামেরা লাগানো লোহার খুঁটিতে একটি লোহার বাক্সের মধ্যে ক্যামেরা সংক্রান্ত যাবতীয় তথ্যপ্রযুক্তির সরঞ্জাম রাখা থাকবে। প্রয়োজনে সেখান থেকেই ফুটেজ সংগ্রহ করতে পারবেন কর্তৃপক্ষ।

Saturday, April 1, 2017

Difference between Cable and Wire

Difference between Cable and Wire
I found many eSecurity Professional - sales manager confused about cables & Wires. Fundamentally a wire is a single conductor while cable is a group of two or more conductors.
A cable is usually two or more wires running together or bonded, twisted or braided together. They are usually insulated rather than not, which gives them a better protection than just wires. Cables are mainly used to carry electrical and telecommunications signals.
There are various types of cables, including twisted pair cable, coaxial cable, multi conductor cable and fiber optic cable. A twisted pair cable has two cables twisted around each other and is mainly used to carrying signals. A multi conductor cable is made up of many conductors insulated from each other, and is best suited for control. In a coaxial cable, the signal on the two conductors is not same. This is called an unbalanced line and performance on this cable is more stable than on a twisted pair cable. There are three types of fiber optic cables: 
plastic fiber – used for sending audio, 
multi-mode fiber – used for sending data, and 
single mode fiber – seen only under a microscope and has the best performance. 
There are two main types of wires: solid or stranded. A solid wire is usually a long length of single conductor. A stranded wire is many thin strands of wires twisted together. Solid wires offer low resistance and are perfect for use in higher frequencies, whereas a stranded wire has a longer life, due to its flexibility and can be used for a longer period than a single conductor. Wires are mainly used to carry electrical and telecommunications signals, but can also be used in various other forms, from bearing mechanical loads, to heating, to even in jewelry and clothing. The easiest way to distinguish between the two is that the wire is usually visible, whereas a cable is most usually insulated.
A detailed comparison between wire and cable:-

Wire
Cable
Definition
Single conductor
Two or more conductors
Uses
To bear mechanical loads, to carry electricity and telecommunications signals, heating, jewelry, clothing, mesh, automotive or industrial manufactured parts, pins, needles, fish hooks, bulbs.
Power transmission, to carry electricity and telecommunications signals.
Types
Solid wire, and stranded wires
Twisted pair cable, coaxial cable, multi conductor cable and fiber optic cable.
Advantages
Solid wires are perfect for use in higher frequencies, offer low resistance. Stranded wire shows higher resistance to metal fatigue.
Higher strength, heavy duty, insulated.

Sunday, March 26, 2017

PoE Access Control Systems

PoE Access Control Systems

Is PoE technology a viable solution for your access control system?

Power Over Ethernet is being widely advertised as a panacea for access control system users. Certainly we have all looked forward to the day when a single network drop at the door will satisfy all of the system wiring requirements between the controller and the doors. One simple cable that will replace the multitude of cables currently needed for reader communications, request to exit, door position, and lock power.

As is commonly the case, along with technology that is new to our industry comes advertising claims and counter claims by various vendors each vying for a prominent spot at the top of the tech-tree. This paper will address this emerging technology, the standards that guide it's implementation, and the claims that warrant further scrutiny. Its focus is to help you sort out what is viable in real world applications and what is advertising hype.

The Objectives of PoE
The primary objective of any PoE system is to reduce costs. The technology was designed as a solution for the implementation of various network appliances in applications where it would be too expensive or inconvenient to provide a separate power supply and wiring. It is commonly used to power wireless network access points, remote network switches, and IP telephones. Stringing wire throughout a building for a proprietary access control network has long been a cost prohibitive proposition and often the most expensive part of the total system. Certainly if any system commonly found in today's modern building needs an alternative to hardwired devices, it is the access control system.

Cost of wire
Although not as costly as the labor needed to install it, the various combinations of wire needed for a full fledged access control system can represent a significant cost. For today's typical system you will need a 6 conductor, 22 AWG, stranded, shielded for the reader; a 4 conductor, 18 AWG, stranded for lock power; a 2 conductor, 22 AWG, stranded for door position; and a 4 conductor, 22 AWG, stranded for request to exit. The outer limit for this wiring architecture is usually 500 feet and is often pushed to that limit. The advent of modern customized bundled cables allows the required combination of conductors to be incorporated into a single cable which makes installation much easier but can still represent a significant cost. By injecting power onto the readily available, commonly installed CAT 5 or CAT 6 cable, PoE promises to bring down the cost of installation.

Cost of labor

If you have ever been on the pay check writing, or even cost estimating, end of a security system installation contractor you clearly understand that labor will represent the bulk of the costs associated with providing today's systems. The installation of wire is responsible for the lion's share of those labor costs. A "rule of thumb" that has long been used in the industry is the 60/40 rule. This rule states that roughly 60% of your costs will be in labor and the remaining 40% will be in equipment costs. To the extent that this rule is true, innovative alternatives such as PoE can dramatically reduce the overall cost to the end user for these security related systems.

PoE System Components
Along with the CAT 5 (or better) cable infrastructure, a basic PoE system will consist of powered devices (PD) and power sourcing equipment (PSE).

Powered Devices: An example of a PD is PCSC's Fault Tolerant (FT) access control system door interface module (DIM). The DIM is installed away from the Master Controller (MC) and near the associated door. Through the DIM, power is distributed to the reader, door locking mechanism, and request to exit device (REX). The door status switch and and REX status are also monitored by the DIM.

Power Sourcing Equipment:

This switch was designed to meet the below detailed IEEE P802.3at specification and specifically for networks consisting of IP video cameras and other security related devices.


Relevant Standards

PoE - IEEE P802.3af - 2003f: Since 2003 the applicable IEEE standard for PoE has been P802.3af. This standard calls for a maximum allowable 12.95 watts of power per port and allows the use of CAT 3 cable. As PoE has become more popular, more and more devices have been designed for its use. The power limitation of this standard has stifled the device manufacturers ability to meet the demands of the marketplace.

PoE Plus - IEEE P802.3at
The new PoE Plus (or Hi PoE) standard is nearing completion and is expected to be ratified soon. Switch manufacturers are already producing switches that conform to this standard, at least to the extent that they can anticipate the final standard's requirements.

It is important to note that PoE Plus requires the use of Cat 5 (or better) cable. The eight wires of CAT 5 cable verses the four wires of CAT 3 allows more power to be transmitted.

Draft 3.0 of the new AT standard, dated March 2008, states that the maximum current will be nearly twice the current allowed under the AF standard.

One objective of the IEEE P802.3at Task Force was to ensure that PoE Plus will operate in modes compatible with existing requirements of IEEE P802.3af. This is good news for forward thinking companies that have already made a significant investment in PDs designed to the older standard. Another objective of the Task Force requires PoE Plus PDs, which require a PoE Plus PSE to provide an active indication of that requirement when connected. This will alleviate the inevitable problems caused by connecting PDs designed to the new AT standard to PSEs that comply only with the older AF standard. Conversely, PoE Plus PDs that operate within the more limited power range of P802.3af will work properly with 802.3af PSEs.

Power Requirements
Power requirements for PDs vary according to the device type, manufacturer, load, cable length, and other factors. Our example PD, PCSC's FT system DIM, requires 200mA at 12vdc or 2.4W. A typical door locking mechanism may require 500mA at 12vdc or 6W. A REX sensor may require another watt. A card reader may require 3W. Even without allowing for environmental factors and cable length, a fully loaded access control system can easily start to approach the upper limit of the older AF standard.

Powered Device (PD) at the door / Required Power
Door Interface Module (DIM) / 2.4W
Reader / 3W
Lock / 6W
Request to Exit (REX) device / 1W
Total / 12.4W

Back-up Power
One of the biggest advantages offered by the PoE infrastructure is the inherent ability to facilitate system wide power back-up. If your system is PoE based, then backing up power for the entire system is simplified. Employing an emergency generator or a network UPS will ensure that the access control system continues to be fully functional during a power outage. Legacy systems typically employ battery back-up techniques that fail to provide sufficient power for critical components such as door locks or request to exit devices.

Security for the Security System
When considering PSEs for PoE based security systems look for features that will provide protection for the system that protects your facility. Temperature will greatly affect the performance of your PoE system. AFI's C10e switch, for example, provides local and remote environmental sensing and alarm generation. If a fan fails and your PoE switch is overheating, you want to know about it immediately. A good PoE command center will also have the ability to constantly poll activity on the power output ports to establish trends and anticipate problems.

Power Sharing
Caveat Emptor: An important concept to recognize when considering the deployment of a PoE network is that of power sharing. This concept has largely been ignored by PoE marketeers. Simply stated, power sharing is when the total power available from a PSE is shared across all of its ports. So if the PSE delivers 12.95W of power and 9 or 10 watts are required on each port, your PSE will only power one port. The slight of hand that the industry marketing fails to acknowledge is that yes, while you can power your access control system with an older IEEE P802.3af PSE with 12.95W of available power, they don't tell you that you'll need a switch for every access control door in the system. Not every pre-IEEE P802.3at switch employs the power sharing principle, but it is something that any potential PoE system user needs to be wary of.

Today's Switches: Newer systems, such as our example of American Fibertek's Commander C10e switch do not utilize this methodology. Each port can be configured by the operator to deliver a specific class of power. This ensures that your purchase of an 8 port switch will enable you to power the PDs required at eight different doors if needed.

Conclusion
PoE is quickly becoming a viable alternative for access control system designs. Network switch manufacturers, like American Fibertek, are producing power sourcing equipment (PSEs) designed specifically for our industry and at least one access control manufacturer (PCSC) offers PoE capable powered devices (PDs) for their new Fault Tolerant (FT) access control system.

Well designed PoE based access control systems will:

1.) Utilize PSEs that avoid power sharing across the various PoE ports of the device.
2.) Comply with the new IEEE P802.3at standard including CAT 5 or better cable and Hi PoE power availability.
3.) Incorporate a cascading technique that employs smaller switches in a distributed architecture.
4.) Consist of PDs that have been designed and tested to meet the PoE Plus standard.
5.) Incorporate power back-up systems that keep the access control functioning during a power failure.
6.) Have built-in protection features that help your security system stay secure.

The long awaited panacea for access control systems may very well be a reality given the new, soon to be ratified, IEEE P802.3at Power Over Ethernet specification. Be careful when looking through the marketing hype to identify those access control system and PoE device manufacturers that understand and conform to the developing industry standards.


Friday, March 17, 2017

Dual Network Interface DVR and NVR Benefits

Dual Network Interface DVR and NVR Benefits

NVRs / DVRs that have dual NICs. If you don’t understand “dual NIC”, what I mean is that it has 2nos Ethernet ports (LAN Port). Customers are wondering what is the need for two NIC cards in the back of the unit. To answer the question, “What is the reasoning behind the two Ethernet ports (NIC) on my NVR?” there are three advantages to having these dual NICs. Based on the network you have, or want to have, you may not be interested in any of these advantages. Let me be clear when I say just because your NVR has them you do not need to occupy both NICs. However, if you are going to use only one Ethernet cable make sure it is plugged into port# 1. That being said, the general advantages for Dual NICs are Multi-Address, Fault Tolerance, and Load Balance. If you do not know what these mean don’t feel bad, you will have a better understanding once you finish this article.
First of all, allow me to explain what Multi-Address means/does. Multi-Address is a tool to have two different IP schemes connected to your NVR, obviously your main network will be for the NVR and will plug into port# 1, then the reasoning for port #2 will be for a switch, whether it be PoE or not so your cameras and NVR will not be on the same network. The advantage to this is the NVR will be on your everyday network, and the cameras will be on a separate network. So if you have a 32 channel system and don’t want 32 IP cameras bogging down your main network you can have them separate from the NVR on the main network but still be able to add them with no problems.
 First of all, look at the bottom picture, this just shows you that the NIC on the left is port #2, and the NIC on the right is port#1. So in my demo, the white cable will be my main network going to the NVR, and the yellow cable will be my secondary network that plugs into the POE switch for my cameras. The other two pictures are showing you the configurations you will need to make in the network tab. The top picture being the main network in “Ethernet1” configured as “Multi-address”, with a gateway of 192.168.1.1 and an IP of 192.168.1.108. The middle picture is showing you the secondary network for the cameras in “Ethernet2” configured as “Multiaddress”, with a gateway of 192.168.2.1 and an IP of 192.168.2.106. It is crucial that the two networks be configured with different gateways and IP’s, otherwise you will cause a conflict and this will not work.
Another thing you will need to know is when you go into “Remote Device” and try to add the cameras while they are on the secondary network, keep in mind the “IP Search” WILL NOT find them. You will need to do a “Manual Add” and when you do so the gateway will be 192.168.2.1 and the IP address will be 192.168.2.? whatever you configure. As long as you follow those simple steps you will be good to go.
Now, the second advantage to the dual NICs is something called Fault Tolerance. In simple terms, you can have your NVR wired to two different switches on your network. The benefit to this is if one switch goes down, the NVR will swap over to your secondary switch, letting your NVR remain operational. So say you have switch “A” wired to the first Ethernet port of the NVR and switch “B” wired to the second Ethernet port. Switch “A” is going to be your primary switch, where your NVR will pull its connection from all the time. Switch “B” is going to be your secondary port, where your NVR will pull its connection from if switch “A” was to go out. The way you configure this is extremely easy. In the network tab you will need to change the “Network Mode” to Fault Tolerance. Once you do so you will see that “Default Card” changes to “Primary Port” and that is where you will configure switch “A” to be your primary switch and switch “B” to be the secondary switch. After you make those few simple changes you are all set. If for some reason switch “A” goes down, switch “B” will kick in automatically, allowing your system to remain operational. The picture below shows the jump from switch “A” to switch “B” happening, how quick it works, and you do not have to do anything. Look at where the ping is going steady, then I disconnect the power from switch “A”, you see it timed out once, and immediately switch “B” kicked in and the ping remained steady. This just goes to show you how quick the NVR does this by itself, no command necessary from you.
The third advantage to having dual NICs is a little something called Load Balance. This means exactly what it sounds like, it is balancing the load on your network. This configuration will require a piece of equipment that we do not offer, something called a managed switch. The managed switch manages the load on your network and keeps the balance nice and steady. So, if your network is being bogged down, the manage switch will take things from your main network and switch it to the secondary network, so your connection never loses its strength. Now, the configuration starts the same way above. Change “network Mode” to Load Balance and set port#1 to be main and port#2 will be secondary. Also, say you do not want to buy a managed switch and so you think load balance is useless to you. You are wrong, there is a way you can still use the configuration. Each NIC is 1Gig of throughput data, if you set network mode to Load Balance that combines the NIC’s and now you have 2 Gigs of throughput data. There are a few things that make that worth your while. You can increase the resolution of your IP cameras and you can increase the bandwidth of the cameras. I’m sure there are quite a few more, but I will keep it as simple as possible. Those are all the things that are beneficial to you with the NVR’s with dual NIC’s. Hope this was helpful.

Sunday, March 5, 2017

Access control in education sector

Access Control in Education Sector

Controlling access to school campuses and buildings is an important issue for school administrators. They need to maintain a user-friendly, welcoming school climate while ensuring that the facility is safe and secure, both when school is in session and when the buildings are unoccupied.

What is access control?
Access control provides the ability to control, monitor and restrict the movement of people, assets or vehicles, in, out and round a building or site.

Access control is essential for all businesses to protect people and assets and has the added benefit of being expanded from controlling, for example, a single entrance door, to a large integrated security network. There are also huge potentials in terms of integrating HR and other systems, such as Time and Attendance, Visitor Management, ANPR, Fire, Intruder and CCTV, which can cut costs and streamline administration costs.
What risks does the average office face and how can these be countered by access control?
Electronic access control systems are increasingly being used to enhance safety and security in educational establishments.

The average educational establishment has a transient population with many high value goods such as computers and IT equipment, not to mention the personal possessions of staff and students, which are extremely attractive for thieves.
Access control systems are all designed to allow access only to people with the necessary authority to ensure that goods and people are protected.

Educational establishments have a duty of care to provide a safe environment for pupils and staff and the application of access control can therefore help manage known or anticipated threats.

Generally systems comprise three component parts:
1. The physical barrier – to physically restrict access to a building or location via such methods as:
• Doors: secured by either a electromagnetic or strike Lock or can be revolving or sliding.
• Turnstiles and speedgates: designed to limit access to one person for one card presented.

2. The identification device – There are a number of different technologies used to identify users of an access control system, such as:
• A proximity card and reader using RFID – cards can either work at a short read range or a long read range.
• A smart card and reader.
• A swipe card and reader.
• PIN pads.
• Biometric (fingerprint, iris scanning).

3. The door controller and software – The door controller and software are at the heart of the system and are used to decide who can gain access through which access point at what time of the day. These can vary dependent on the size of the system and how many readers or sites you are trying to control from one point.
Some of the options include:
• A standalone door controller linked to a single door with no software.
• A number of door controllers all linked together to a single PC to control one site.
• A number of sites all interlinked together over a wide network area.

What added benefits can access control systems bring to educational establishments?
Protection during school hours is paramount, and the following added benefits come from access control:

Visitor monitoring
In an environment where visitors can blend in with the staff and pupils, the use of PC and computer networks should be considered. These systems can print photographic ID and allow access to be restricted to certain areas within the office. Moving to a software solution for visitor management is an easy and inexpensive solution and can provide a number of added benefits.

The system was designed to ensure the smooth operation of a 100,000 square metre complex, spread over five buildings with both students, staff and visitors accessing the different facilities sometimes at high volumes. A Smart Card system was developed which provides not only access to designated areas, but also allows all sites to be linked via a modem, allowing administration from a central point.

Automatic Number Plate Recognition
For college and university sites where students may be driving in and parking onsite, Automatic Number Plate Recognition may be a viable option. To monitor the entrance of vehicles on site, CCTV-style cameras and computer software can be used to identify number plates of vehicles. Some systems can also store photographs of the driver and vehicle for subsequent analysis. This sophisticated software allows critical information to be passed to the police to assist in the pursuit, identification and capture of offenders.

What key considerations should be taken into account when considering access control?
The outcome of the risk assessment for your office will determine the level of security you require and in turn influence your choice of access control system to be used. BSIA access control members and professional security consultancies can assist with this.

BSIA members go through rigorous checks before they are admitted into membership, meaning you are selecting quality companies to achieve peace of mind. Below are just some of the reasons why you could benefit from using the services of a BSIA member:

·        Independently inspected to the quality standard ISO 9001 with a UKAS accredited inspectorate.
·        Compliant with relevant British and European Standards and codes of practice.
·        Financially sound.
·        Professional.
·        Staff vetting conducted (where appropriate).
·        Technically proficient.
·        Committed to quality training and development.
·        Up-to-date with the latest developments in British and European policy and legislation.

Is there any legislation I should be aware of?
The Disability Discrimination Act was amended in 2005 and has significant impact not only in terms of the design of new systems, but also means that many systems may need to be upgraded to ensure compliance. This is of particular importance also for educational establishments as employees, pupils and visitors will all need to have adequate and user-friendly access to the building.
The BSIA has created a guide to help design access control systems following the introduction of the revisions which can be downloaded from www.bsia.co.uk/publications

Other legislation to be considered in relation to educational establishments is:

National minimum care standards
Health and Safety at Work Act
Occupiers Liability Act
Management of Health and Safety at Work Regulations


Sunday, February 26, 2017

Interpretation of Intrusion Alarm Power Supply

Interpretation of Intrusion Alarm Power Supply

BS EN 50131-6: Alarm systems Intrusion and hold-up systems: Part 6: Power supplies, was revised and re-issued as EN50131-6:2008.

This document has been prepared to give guidance on the interpretation of some of the clauses in the standard that are in need of further clarification. It is intended that this guideline can be used by manufacturers to self- certify their products to conform to the standard. This guidance document may be further revised as required.

Only those items in BS EN50131-6: 2008 that have been the subject of formal comment by BSIA members are listed below. All other clauses or parts of the standard are believed to be self-explanatory. 

Advisory note:
This guide has been produced for use in PD6662:2010 Scheme for the application of European standards for Intruder and Hold up alarm systems. BSIA has produced other guides specifically for the PD6662:2004 Scheme, which may not be appropriate for this scheme.  Therefore you should seek the appropriate guidance.  

Power Sources
There is inconsistent usage of PPS (Prime Power Source) and EPS (External Power Source) in the EN50131 series of standards.

Figure 1 shows the relationship between each of these entities, as used within the standard. Essentially the PPS is the national grid mains supply. In those installations having a standby generator capability e.g. hospital, then the standby generator is the SPPS. The (mains) power input to an I&HAS may come from either source (PPS or SPPS) of which the I&HAS may have no knowledge and this input is therefore generically known to the I&HAS as the EPS.

The APS is typically represented by any local standby power source (e.g. rechargeable battery) within the design and control of the I&HAS that can power the I&HAS (or part thereof) for a predetermined period of time in the event of loss of the EPS. Note that from EN50131-1 clause 9.2, if an SPPS is automatically switched into operation on loss of the PPS, the overall system standby period from the APS is reduced to 4 hours for I&HAS grades 2, 3 and 4.

EN50131-1 and TS50131-7 do not use the term “EPS” and refer to the immediate power source of the PS consistently as the “PPS”. 

Power Supply Rating
The rating of the power supply (PS) is the total continuous output current capacity of the PS when operating under all conditions of EPS or from a SD of capacity as defined by the PS manufacturer for a grade dependent time. This is the output current that is available to power system components and does NOT include the additional current that is used by the PS to recharge any attached storage device. Note that where the PS is integral to another component e.g. a CIE, then the rating of the PS should exclude the CIE and the manufacturer should declare the CIE current consumption separately as a system component.
Note: the PS manufacturer must clearly state in the product documentation that the total PS rating must not be exceeded where independent power outputs have continuous rated outputs, the sum of which is greater than the total PS rating e.g. multiple fused connections.

Interpretation (ব্যাখ্যা) of clauses
Clause 3.1.4 independent power outputs
This clause refers to completely independent outputs from a power supply where a short circuit and/or overload on one output will have no affect on the others. Each output may have multiple connections. Simple fused outputs may not qualify as being independent if an overload or short circuit on one has an effect, even if only transitory (e.g. during finite time for fuseable link to fail), on another.


For the purposes of this interpretation the following diagram gives a typical example.
Example general arrangement of PS and CIE with independent outputs
In the example shown in Figure 1, O/P 1 and O/P 2 may only be considered independent power outputs if applying a short circuit or overload to one will have no effect on the other. Although the CIE module is connected to the output of the regulating element, this connection is not considered an independent output of the PS for the purposes of the tests of clause 8.2.


Clause 4.3 APS Capability
Note that there is no longer a table within EN50131-6 for standby capability.
This is replaced by the simple requirement that the PS must be capable of meeting the system requirement of EN50131-1, Table 23.

Clause 4.11 Tamper security
There is inconsistency between the requirements of EN50131-6:2008 and those for CIE in EN50131-3:2009. For consistency, the requirements of EN50131-3:2009, clause 8.7 should be applied.

Clauses 7.19-7.22 Tests (Tamper security)
These tests should be replaced by those from EN50131-3:2009 clause 11.9 (see clause 4.11, above).