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.
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".
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.
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.
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.
