PIR Detection Technology and Reliability Part 2
September 2011
PIR detectors offer highly efficient and intelligent integrated security system options at affordable prices.
Passive infra-red detectors (PIRs) are cost effective, perimeter protection tools, suitable for securing any size of site. In our second article on PIR technology, Graham Creek, MD of Luminite, the UK-based PIR detector manufacturer, looks at how PIRs can integrate into larger CCTV security systems to enhance their effectiveness. Graham explores the advantages of intelligent PIR system management, including mapping multiple PIRs to each video channel. He also explains how large application challenges, such as the complexity of connecting multiple hard-wired PIRs into a system, can be overcome to achieve convenient and efficient installation.
Why use PIRs at all?
PIRs are most commonly used within the security industry to provide an early alert to unwanted intrusion. They use infra-red body heat emissions to detect a person and raise an alarm. Although video analytics and thermal imaging cameras also offer excellent intruder detection, PIRs provide by far the most cost-effective solution.
PIR operation
PIRs are placed within or around a site perimeter and alert the security system or a remote monitoring station, when an intrusion occurs. PIRs have different lens options to enable short, medium or long-range detection. Alternatively, they can offer vertical and horizontal curtain detection. Options for setting the target size of items within a PIR detection zone can reduce false activations caused by animals and litter. Correct PIR positioning also helps to reduce false activations from detection overspill and foliage.
PIR wiring
PIRs usually have separate connections for power, alarm and tamper. This means that three pairs of wires (six individual connections) are required for each PIR to complete its installation. This is reasonably straightforward for small systems, but can become complex and time-consuming to implement for integrated systems containing a large number of PIRs. The more wiring work that is required, the greater the risk connection errors or accidental disconnections become.
Due to the many problems that wiring and connecting PIRs into large systems can cause for installers, Luminite has developed a wireless PIR range. Instead of the PIRs being hard-wired directly to a DVR, they are connected by wireless, radio-frequency technology, to a Masthead transceiver. It is only the Masthead that is wired to the system DVR, via a control interface and RS232 cable. The next development has been the IP Masthead. This connects the Masthead to a network, using Ethernet cable and TCP/IP protocols and not directly to the DVR. It offers even more integrated system and management flexibility.
Wireless PIRs are battery-powered to enable optimal PIR positioning, with batteries lasting over 2 years. Wireless PIRs are unconstrained by network or power cable locations and require no civil work to install them. They can be positioned along a site perimeter, at their ideal height, looking in towards the site. They are not obliged to be placed on a building looking out. False alarms from animals, litter, overspill and foliage are usually reduced by this type of perimeter installation. Put simply, wireless PIRs make installation quicker and more reliable, detection more effective and reduce false alarms.
Mapping multiple PIRs to each video channel
In a typical CCTV system with hard-wired PIRs, it is most common for each PIR to be mapped directly to a single video channel. Integrated security systems that use management software, enable each PIR to be mapped to multiple video channels. This means multiple system actions can be triggered simultaneously and/or multiple PIRs can be mapped to each camera. The system’s flexibility becomes unlimited.
The management advantages of system integration
PIR management software becomes critical when any combination of PIR activations can trigger any number of system actions. Luminite’s PIR management software can be used on its own, but we encourage DVR and NVR manufacturers to integrate our software into their products. This enables this pro-active management functionality from their operating systems.
Quality PIRs, such as Luminite’s, include tamper, anti-shock, anti-cloaking and intrusion detection, as well as a range of system management alerts like low PIR battery strength and weak wireless signal. The management software enables operators to distinguish between critical and non-critical alarms, enabling integrated NVRs and DVRs to provide intelligent and useful system management information. Critical alarms can alert an operator or key holder to a site incident for an immediate response, whereas non-critical alarms, like a low battery life warning, can be used to remind the installer to schedule a maintenance visit.
An electronic “health-check” is also carried out every few seconds, ensuring that all the PIRs within a system are operating correctly.
Network access means that this functionality can now be set-up and managed remotely by installers, reducing the need for site visits and enabling remote monitoring station access for professional monitoring services.
Integrated PIR systems offer pro-active, site security options, which significantly reduce false alarms, improve detection accuracy and provide superior site protection. Quick installation using wireless PIRs, optimal PIR positioning, critical and non-critical alarm management and the ability to map multiple detectors to each video channel, all enhance site security operation in a cost-effective way.
DVR and NVR manufacturers wishing to include Luminite’s PIR management functionality within their products should contact Luminite on 020 8368 7887 or visit Luminite.co.uk for further information.
Luminite designs and manufactures the wireless and hard-wired Genesis PIR detection systems, built and supported in the UK. For more information on the PIR detection range or for training on PIR installation good practice, contact Luminite on 020 8368 7887 or by email.
