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.

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.

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

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).

HOW TO USE IP CAMERA ALARM I/O

How to use ip camera alarm i/o

As we know, professional IP cameras have alarm input and output interface for security integration solution. Users can use this interface to connect other security devices such as PIR motion sensor, door sensor, perimeter beam sensor...etc. This article is intended to give a guideline for connecting alarm input/output interface of Vivotek, Axis, Sony, HikVision, Dahua, Messoa,...and more IP cameras. 

KNOWING ALARM I/O (INPUT / OUTPUT)

Alarm Input / Alarm Output is a pair of pins in camera's terminal block or connector through which it's possible to connect electronic device with the camera. Alarm Input receives signal from external device, will be triggered from external device if something changes, and Alarm output notifies the external device by the camera upon a event (motion detection, vandalism, video loss).

The terms "Alarm In / Alarm Out" are mainly used as the application for alarm system, but they are also called digital input (DI) / Digital Output (DO) as the common terms.

External device connected to Alarm In can be a switch (or say relay), button or any device which can issue a trigger signal. External device connected to Alarm Out can be a light, alarm horn/siren or any kind of device which receives data.

SHOULD I USE CAMERA'S ALARM I/O?

The main benefit of using camera's Alarm Input / Alarm Output is to respond to the event instantly and automatically by a pre-defined event scheme, and give alert message immediately so that the monitoring control center can handle any situation in a short time to reduce hazard.

CAMERA'S ALARM INPUT/OUTPUT

(1) Terminal Block Type: use 2-pin connector to connect wire

Dahua IP Camera - Terminal Block

Hikvision IP Camera - Terminal Block

Messoa IP Camera - Terminal Block

(2) Connector Type: connect wire directly

*Alarm Out (Orange): Connect to a device that responds to alarm signals, such as buzzers or lights.
*GND: Ground (electricity) in electrical circuits
*Alarm In 1 (Red) & 2 (Brown): Connect to devices that issue alarm signals. Up to two (2) input devices can be selected.

Messoa Camera Alarm Input / Output

CONNECTION EXAMPLE 

1.      Connect Alarm In via a switch to GND: Simply  connecting  Alarm In_1  via a switch to  GND with a single wire,  as shown above, the  Alarm In_1 will be instantly triggered by a press on switch. You do not have to have an external battery to make the “switch” work.
The example circuit of Alarm In: Alarm In 1 –> Switch (OPEN by default) –> Ground

2.      Connect Alarm Out: The Alarm out is an open-drain structure, so you have to  supply external power source  to make the function work.
The example circuit of Alarm Out: DO 1 –> LED (load) –> +[battery]- –> Ground

3.      Enable External Alarm: Access the IP camera via Internet Explorer, go to camera's configuration page to enable External Alarms. Enable the Alarm In/Out that is connected with external alarm devices and set the voltage level as low or high to define the active state.

4.      Validate the setting by pressing the switch and check if it triggers the LED instantly.

The alarm output ports on the back of IP camera can be connected with a siren or strobe light. Below it's a connection example. The goal is to turn the siren/strobe light on when an alarm is triggered. The working theory is pretty simple, you can imagine the alarm output is a turn on/off switch. In below connection diagram, you need to use extra power supply (for example a AC/DC adapter) to provide the power for strobe siren.

For DVR Click at DVR Alarm

The IP camera's alarm inputs are grounding alarm inputs (Normal open or Normal close type). Hardwired sensor or device can parallel connect ground (-) end and COM end of the alarm detector, while parallel connect the NO (+) end and NC end of the alarm detector. (Please note that you need to provide external power to the detectors)

In the above connection diagram, the DG85 (motion sensor)'s NC connects the positive (+) alarm input of IP camera, and the DG85 (motion sensor)'s COM (or GND) connects the negative (-) alarm input of IP camera. (This is NC connection, you need to choose the IP camera's alarm input property to NC.)

You can make connection between IP camera and hard-wired/wireless alarm panel. Connect the alarm output of IP cameras to hardwired zones of alarm panel. Please note that you need to use the EOL resistor in this connection. The EOL resistor can protect the circuit of wiring to prevent short-circuit or cut. The EOL resistor should be installed in the end of IP camera.

With correct connection, the IP camera can send signal to alarm system for associated alarm action.

Two different connection are available:

1.      When alarm output (IP camera) is NC:You need to do the normal close connection. The EOL resistor should connect into circuit in series connection.

2.      When alarm output (IP camera) is NO: You need to do the normal open connection. The EOL resistor should connect into circuit in parallel connection.

Normal Open (NC) and Normal Close (NO) explanation

Normal Open: When the device is in the non-triggered state, it's normally closed means that the circuit can allow current to flow from NC to COM, or it turns ON. When the alarm is triggered, the relay is enabled and it will switch from the normally closed (NC) to normally opened (NO) or from Turn ON to Turn OFF.

Normal Close: When the device is in the non-triggered state, it's normally opened means that the circuit is open, it doesn't allow current to flow from NO to COM, or it turns OFF. When the alarm is triggered, the relay is enabled and it will switch from normally opened (NO) to normally closed (NC) or from Turn OFF to Turn ON.

Factors to Consider When Purchasing a PTZ IP Camera

Factors to Consider When Purchasing a PTZ IP Camera

PTZ IP cameras are commonly used for surveillance in large home compounds and public areas such as commercial car parks, stadiums and conference halls. PTZ stands for Pan Tilt Zoom, and that means you can use the IP software for cameras through the internet or your network to manipulate what the IP camera displays.

Different IP camera brands sport different kinds of zooms, and lower end cameras will simply feature the digital zoom. Proper optical zoom is the recommendable zoom type and this, together with the price, will always be specified in the product description.

Basically, a PTZ IP camera lets the user view real time images of the protected areas over the internet. You can simply monitor your office, home, building, yard or anywhere from miles away using a PC or a high end smartphone, tablet or PDA. Some network cameras even feature built-in Web server functions such that the IP camera doesn’t necessarily need to be connected to a computer.

DESIGN

IP PTZ cameras are traditionally spherical in shape, and this is mainly because they are meant to be completely mobile. Either the network camera itself (the sensor and camera mechanism) has been designed to take the shape of a sphere, and held so that it can pivot accordingly, or the camera is structured more traditionally and cased in a spherical protective bubble where it can tilt, pan and zoom and take images from within the shield.

NIGHT VISION

IP cameras with night vision capabilities come with built-in LED lighting to enable object visibility in dark settings, or at night. For outdoor surveillance, specifically in places without artificial lighting, night vision cameras may come in handy.

PTZ vs PT

Some IP cameras can only pan and tilt but not zoom. The two functions will usually be enough if the area you want to cover is small, like, say, your living room. However, if you want to cover a large area such as a shopping mall, an IP camera with the zoom function will be more effective.

HOW DO THEY WORK ?

PTZ IP cameras are typically controlled using remote systems. Users can do an initial configuration to have the camera moving and rotating in a certain predetermined pattern, or do it manually using a keyboard or mouse controlled interface. The angle of the lens can also be manually controlled, and this facilitates automatic position adjustment of the camera.

BENEFITS OF PTZ IP CAMERAS

·         User does not need to be close to the camera to operate it.

·         Requires little maintenance after it has been installed (except for regular cleaning of course).

·         Has 360-degree mobility. This way, it can detect and track objects as they move in the covered area as long as the target object is within lens range.

Factors to Consider When Purchasing a PTZ IP Camera

INDOOR OR OUTDOOR USE ?

If you’re looking for a PTZ IP camera for outdoor surveillance, you need one with night vision, weatherproof enclosure, miniature architecture for “outsider” visibility reasons, and vandal-proof capability for fortification in high crime areas.

YOUR DESIRED CAMERA FORM FACTOR

Each form factor has its own benefits, and the brand you opt for should cover all your surveillance requirements. Would you prefer a dome-shaped or an inconspicuous mini-dome camera? A wireless option or just an ordinary corded PTZ IP camera? You know your place and specifications best.

LEVEL OF DETAIL

When weighing different camera alternatives, you need to be sure of the detail level you want to see in your images. For wide area surveillance, you need a higher resolution, of course, as this will allow you to view even the furthest of images in relatively great detail.

Another factor that affects a camera’s resolution is its field of view (FOV). This is the viewable expanse of a given scene taken by the camera, and is sometimes referred as the angle of coverage or angle of view. A small FOV generally leads to the target object appearing smaller than it would in a fairly larger FOV.

The type of lens featured in the camera will also have an impact on resolution and field of view alike. A lens with low focal length number will bring about a wide field of view but less magnification while a higher focal length number will provide more magnification.

PTZ IP cameras, just like ordinary cameras, come with different resolution capabilities, and if you choose a high-resolution one, you also need to choose a high resolution megapixel lens so that the resolution required to produce a clear and detailed image can be maintained. If you combine a high resolution camera sensor with a less powerful lens, then your images will not be as detailed and crisp as you may desire.

POWER

PTZ cameras have multiple motors built-in which draw a considerable amount of power compared to a regular surveillance camera. Power can be supplied locally at the camera location or a cable can be pulled from a power source to the camera. The size of the wire dictates the maximum distance the cable can extend from the camera to the power source. See the chart below.

·        12 Gauge Wire – Maximum Distance 320 Feet

·        14 Gauge Wire – Maximum Distance 225 Feet

·        16 Gauge Wire – Maximum Distance 150 Feet

·        18 Gauge Wire – Maximum Distance 100 Feet

Each PTZ camera is shipped with its own power supply. Some cameras operate on 12v DC and some on 24v AC. Make sure you note the type of power the camera uses and that the power supply matches the camera.