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Intruder Test: External Space Detection

Increasingly, external space detection devices are deployed to act as triggers for other systems. Whether used for lighting, surveillance or traditional intruder detection, today’s sensors must offer flexibility, stability and accuracy. Benchmark considers some of the leading units from Bosch Security, GJD, Optex, Luminite and Takex.

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When it comes to intruder alarm detection systems, external space detection is still a peripheral option for many installers and integrators. Typically, the weapon of choice in such applications is active infrared beam sensors. Many still feel that space detection devices – usually PIRs or PIR and microwave combinations – are vulnerable to nuisance activations in more unstable environments.

The general perception that outdoor detection devices are susceptible to false alarms is somewhat outdated. Credible manufacturers have enhanced product design over the years, and external detectors can often be more stable than average internal sensors!

Too often the focus for external detection devices falls onto stability … and stays there! In external applications, there often aren’t any false alarms, but instead there are nuisance alarms. Something will trigger the detector; it’s just not what the user thought it might be!

In truth, the issue of catch performance is far more important than stability. Nuisance alarms will happen in an external environment, and when designing a system this has to be considered. However, missing a genuine event is more critical, because the point of external detection is to identify threats, usually intruders, before they have an opportunity to cause loss or damage.

To counter nuisance alarms, installers and integrators often look to external space detection to trigger video and surveillance-based systems. This Benchmark test looks at the use of space detection devices for triggering video elements in the protection of a courtyard area.

Bosch: OD850
The OD850 from Bosch is a TriTech outdoor detector which uses passive infrared and 10.588GHz microwave technology. It has a range of 15 x 15 metres. Mounting height is 2.1–2.7 metres.

The sensor makes use of Motion Analyser II signal processing to manage the PIR element. This effectively analyses the amplitude and duration of activations to filter out unwanted information. The microwave element of the detector employs Linear Travel Distance processing, which ensures that moving objects also travel before generating an alarm condition.

At first glance, the OD850 looks like an oversized dual technology detector, and to all intents and purposes that’s what it is. The tamper-protected mounting plate is retained by the use of a twist-lock fitting, and once removed it reveals the connections and configuration DIP switches.

Wiring connections are straightforward and clearly marked. There is also a potentiometer for microwave range. There are 7 DIP switches, but only 5 are operational. These are for LED enable/disable, PIR sensitivity (standard or intermediate), timed relay outputs (a combination of 2 switches is used, and options are 2 seconds, 1 minute, 5 minutes and 10 minutes) and AND/OR mode.

In our opinion, the microwave element of a dual tech is the less stable one, as it is affected by some environmental issues that are difficult to eliminate. Bosch uses Linear Travel Distance (LTD) to detect if moving objects are also travelling, and this does seem to work well. Despite this, our instinct was to stick with AND mode.

Once settled, the detector operated consistently within the performance parameters expected. Stability was good, and whilst it is possible to create nuisance activations, the use of the AND mode meant that these weren’t a problem. Many of the typical microwave nuisance alarm sources didn’t affect the detector.

Catch performance was very good, with all genuine intrusions being detected. Typical attempts at cloaking motions were detected, and we had to resort to a high level of subterfuge to pull off a masking attempt. As a Grade 2 device, anti-masking is not to be expected from the unit.

The only negative we could find is that the OD850 is an intruder detection device, and so lacks the adjustability that surveillance-based units offer.

GJD Security: D-Tect3
The D-Tect3 from GJD Security is an external detector with a range of 30 x 30 metres. The detector makes use of both PIR and 10.587GHz microwave technologies. Mounting height is 3 metres, but this can be increased to 6 metres if required.

The D-Tect3 is the epitome of a sensor designed for use with a video surveillance system. Mounting flexibility includes the ability to tilt the detector through 45 degrees and pan through 90 degrees. Additionally, the detector features ‘curtains’ which allow the coverage pattern to be adjusted if required. This, along with more traditional masking, ensures that the detector’s field of view can easily be customised. Replacement tamper switches also allow for uneven mounting surfaces.

The sensor features two volt-free and two negative switching outputs. Installation is simplified through integral EOL resistors; these are set via two banks of jumpers.

The opaque cover of the detector is retained using a screw, and once removed the connections, jumpers and configuration button are revealed. Alignment of the detection head is simple, and clear marking assists with this.

Anyone who has used a detector from this range will be familiar with the way in which the configurations are set. It might be a bit odd if it’s the first time you’ve encountered it, but it does allow a good degree of flexibility.

Each option has a number (1 for Range, 2 for Pulse Count, etc.) and each option has a value too (for Range, it’s 1 for 8m, 2 for 15m, 3 for 20m, 4 for 25m and 5 for 30m). If you wanted to change the range you push the button once (to select Range), and it will then flash to identify the current setting (4 times, for example, if it is set to 25m). If you wanted to change the setting to 15m, you then press the button twice.

Here’s a tip based upon experience: write down the settings you want to change, along with the associated numbers, before starting the process!

The settings include range (in metres), pulse count, LED, S-Output lux level, contact configurations and relay timer.
There is an optional walk test unit available for the D-Tect3. Once set up, the D-Tect3 delivers consistent and reliable performance. Stability gives no cause for concern, and the vast majority of nuisance activations were ignored. Despite this, accuracy was high and all genuine intrusions were detected as expected.

The flexibility with regard to positioning worked well and allowed a good and accurate alignment with linked cameras. In video applications, that alone is a significant benefit.

Luminite: LG2HW 6004
The LG2HW 6004 from Luminite is a PIR detector designed for outdoor use. It forms a part of the Genesis 2 range of products. The detector features a long range coverage pattern of 60 x 4 metres. Mounting height is 2.5 metres, but this can be extended to 4 metres with mirror adjustments.

The sensor utilises black mirrors; these absorb white light, thus reducing some of the sources of typical nuisance alarms.

Other features include shock and anti-mask sensing, and AND/OR detection modes. The unit has a Quad in-line PIR sensor which acts as two discrete sensors. In the AND mode, both must sense an activation for a signal to be generated.

The detector is a fair size, and that’s a legacy of the mirrors. With the cover and mirror assembly removed, the various connections can be made. With the mirror refitted, the detector can be aligned. The sensor and mirrors can be rotated through 180 degrees (there are ‘coarse’ and ‘fine’ adjusters for this) and tilted through 20 degrees.

The Genesis 2 detector uses a button and LED set-up for configuration. The buttons are for navigation, plus Select and Save. The LED uses codes to identify the setting being changed. Choice include alarm and tamper relay states, activity time, pulse count, sensitivity (10 levels), AND/OR, power saving, Easyswitch mode and time adjustment.

The walk-test process is straightforward, and an optional walk tester is available. If you want to adjust the range, this requires either decreasing or increasing the sensitivity. Whilst this won’t be an issue in some applications, it does raise the question as to how you’d configure the device for high sensitivity in a low range application or vice versa!

The detector supplied did not meet the specification requested, so some of the tests could not be completed. However, in long range mode it operated consistently and stability was good, as was catch performance. Typical attempts at cloaking motions were detected.

The main negative for the product has to be using sensitivity to adjust its range.

Optex: SIP-3020/5
The SIP-3020/5 from Optex is a part of the company’s Redwall V range. It is an external PIR detector with a range of 30 x 20 metres, and is designed for use in video surveillance applications. Mounting height is between 2.4 and 4.0 metres. The unit also includes a discrete PIR on its base for creep protection.

Other features include automatic sensitivity adjustment based on light and temperature, anti-vandalism features and intelligent adaptive signal processing.

The detector is provided with a masking kit, and according to the manual there are also some optional but necessary parts required from the manufacturer for product adjustment. Many manufacturers offer optional tools, but we question the approach if they’re deemed ‘necessary’. One is a visual alignment tool (similar to those provided with IR beams) and the other is a walk tester.

Despite this, installation of the detector is simple. Wiring connections are made via the cable-managed bracket and are straightforward. Removing the cover plate reveals 4 DIP switches, 3 sensitivity adjustment switches and a connection for the walk test unit. Alignment uses the visual tool and a detection area plate, and this is then verified using the walk test tool.

Once aligned the configurations can be finalised. These include setting the sensitivity for the far area, near area and creep zone. The DIP switches are used to set AND/OR, detection range (effectively deactivates the far detection zone) and alarm interval time.

Once aligned and configured, it was no real surprise that the detector operated consistently. The Redwall range has been around for a long time, and still is in demand.

Stability was good throughout the test, and the very occasional nuisance activation actually triggered the other detectors as well. The SIP-3020 is consistent, detecting all genuine intrusion attempts and all potential sabotage attempts.

Catch performance was very good, and delivered accurate and timely detection. Attempts at cloaking were foiled, and even extremely slow movement was detected immediately.

Takex: PIR-T15WE
The PIR-T15WE from Takex is a PIR detector designed for outdoor use. It offers four operational modes to meet the needs of differing applications. Detection range is 15 metres, and the coverage pattern varies between 80 and 85 degrees dependent upon the selected mode; this also affects the mounting height, which can vary between 2 and 6 metres.

The modes allow for standard operation with a high position and low position mode, and specialised operation. The latter includes pet mode and high density mode for high ceilinged areas.

The sensor utilises a triple mirror set-up with fuzzy logic processing. Other features include pet immunity, detection area adjustment and a dual output to allow triggering of secondary devices. The housing is specified as IP55.

Like the Luminite unit, the mirrors do add to the size of the Takex detector. With the cover removed, the layout is reminiscent of some other high end detectors from Takex. The detection assembly can be adjusted to allow a precise degree of alignment, and is well constructed too. It also is easy to pop out, allowing access to the wiring terminals and DIP switches.

Wiring connections are clear and well marked. The switches cover LED, alarm memory, sensitivity, environmental adjustment, operation mode, creep zone, walk test, LED memory, contact status, secondary output, near area disable and a long-term health check function.

Once settled, the detector is impressive. Not only did it cope very well with the standard tests, but when we pushed it a bit to see how the other modes worked, it took pretty much everything in its stride. Like the Bosch unit, it doesn’t have the flexibility of positioning some of the more CCTV-centric detectors enjoy, but it still is more than capable of delivering a good level of triggering.

The detector was consistent with regard to both stability and catch performance. Whilst it ignored the source of many nuisance activations, it also detected all genuine intrusion attempts, including cloaked events.

Verdict
The OD850 from Bosch is less suited to surveillance applications than the other units, but despite this it still delivers a good level of stability and catch performance. The Takex unit is a multi-purpose detector, and would fare better in a alarm-based test. However, it still did well in this company.

GJD and Optex both have well established detectors for video switching, and both performed as expected. The Luminite unit was only slightly off their heels.

In truth, the real differentiator for these detectors will be the needs of the given site!

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