The bench test 1 - A sensor style

What our experts say …

The more things change, it seems, the more they stay the same.

False alarms and the efforts made to reduce their occurrence have been in the news again recently, with the BSIA launching its intruder alarm strategy, and the government passing a law which deals, in part, with noise pollution caused by false alarms at residential and commercial premises.

The onus, then, is not only on installers and end users to aid in reducing false alarms, but on manufacturers to provide suitable equipment for this purpose.

Takex is making an effort in this regard, and is doing so by beginning with the humble PIR.

Takex, formerly known as Pulnix, has produced security sensors and industrial automation sensor applications since 1982.

The company is based in California, USA and manufactures as the Takenaka Sensor Group in Japan, marketing its products throughout the world.

Adjustable range

The Takex MS-12FE is a new, externally rated passive infrared movement detector with adjustable range and catch characteristics.

Most installers will be entirely familiar with the name Pulnix, and indeed with its portfolio of external detection products.

The Pulnix Quad and Twin infrared beams, for instance, have been market leaders for decades, and the MS-12FE is a logical addition to those products.

In fact the 12FE has more in common with an active infrared beam than a normal PIR when comparing style, price and concept.

This detector is specifically designed to be mounted from 0.8 - 1.2m in height and is expected to be specified for perimeter type detection for CCTV and access control applications in the upper domestic/commercial market, where the issue of price is superseded by requirements for a high level of stability to cope with expected environmental problems, such as animals or wind blown debris. We were quoted a trade price of £96.92 + VAT from a local distributor, though they did not have any in stock at that time.

Although not visibly marked with the information, the Takex website technical literature displays the CE mark for European compliance, and the unit comes with a very reasonable five year guarantee.

Construction and design

The housing is constructed from AES resin, a Styrene based engineering plastic well suited to external applications, and looks very much like the established range of active infrared products available from Takex.

The cream colour is inoffensive and the twin black fresnal lenses give a professional, though somewhat commercial feel.

The lenses in particular are very strong and resistant to finger poking - as indeed they would need to be given the proper mounting height.

As expected, a red LED illuminates through the cover to give walk test information, and though the LED can be deselected inside the unit, the change over relay is loud enough to be heard in quiet environments.

180 degree rotation

A single recessed screw allows the cover to be removed, revealing the two vertically stacked PIR units, each of which can be rotated horizontally by 180 degrees.

Vertical adjustment of each sensor is achieved by sliding an integrated mask up and down against a calibrated reference.

By using these settings and the supplied self adhesive masking sheet, together with the sensitivity and day/night photocell potentiometers, an enormous amount of tweaking is available to the installer to get things just right.

The technical literature does not give a specific IP rating, and though the optical chambers themselves are not specifically sealed against dust and insect intrusion, the unit looks to be sufficiently well waterproofed for external use, providing the mounting surface is relatively smooth and flat.

One thing that is not flexible is the mounting height. It should be noted that the MS-12FE is very much designed to discriminate against pets and ground level movement and this can only be effected by fixing at the recommended 1.0m height.

Increasing the mounting height above 1.0m will of course give greater horizontal coverage at the expense of proper vertical operation of the two detection sensors.

Selectable delay

The connections are printed on the PCB using conventional terminology, and include the facility to render the output terminals to either normally open or normally closed to suit the application.

A series of DIP switches are included to allow the installer to select features such as pulse count damping, movement sensitivity, and day/night operation modes using the on-board photo sensor.

Unusually, the installer can select an operational delay of the change over relay of up to five minutes.

Although the delay potentiometer is not calibrated, this feature, together with the wide voltage range, could be useful for very long cable runs, possibly for triggered lighting applications. There is enough space inside the unit for wiring including an ‘ADE' biscuit if using point ID configuration.

One interesting and useful feature is the facility to select either the ‘AND' or ‘OR' configuration for the pair of sensors. Essentially, the sensors can be made to operate the output change over relay when either one or both PIR sensors have been activated.

This configuration will depend very much upon the particular application, but needless to say the maximum immunity to false alarms will be achieved using both sensors working in parallel.

Performance

We found the current consumption to be less than the quoted specification, at 28mA, dropping slightly when the LED was illuminated. And though the detector is designed to operate at a nominal 12v DC, the voltage range is said by Takex to be usable from 12v-30v DC.

The relay output gave a reading of less than 1 ohm for a change over period of around three seconds.

The technical literature gives an impressive operational temperature range, from -20 degrees C to +50 degrees C. That should just about cover it for most UK situations.

Each of the fresnal PIR lenses is segmented into 14 pairs of zones, but however the sensor head is aligned, it will only look through seven of those zones at any one time.

This is not a dense level of coverage for a modern sensor, but the unit did perform well with a reasonable catch at maximum distance (12 metres) and good stability throughout the test.

There is no look down or ‘creep' zone immediately beneath the detector but this would be self-defeating given the purpose of the design. It is important to note that although the individually adjustable sensor heads can be rotated through 180 degrees, the coverage itself is restricted to 90 degrees.

Instructions and support

The accompanying instructions are provided in an eight page booklet with mostly schematic diagrams for identification of parts and coverage patterns for the PIR detection area.

The instructions are methodically laid out and written in reasonable English with installation guidelines in text and pictorial form, including explanations of the ‘AND' or ‘OR' technology.

A specification is included with all the information required by an installer, ie current consumption, operating voltage, detection range and temperature requirements.

The telephone number for the Takex Europe switchboard is provided at the back of the book, which we called during working hours and asked for technical support. The technician had all the relevant answers to hand and was polite and patient.

What the manufacturer says ...

The MS-12FE is designed to overcome the traditional problems associated with using external PIRs.

Consisting of two separate and/or gated 90 degree PIR elements, both of which can rotate through 180 degrees, this unit offers up to 180 degree protection with a range of 12 metres.

Couple this with the day/night sensing, variable relay timer from five seconds to five minutes, selectable no/nc output, and the versatility of the MS-12FE becomes apparent. Where this unit excels, however, is the dual zone coverage of each PIR.

Each has a horizontal plane and a downward plane, both of which need to be activated to generate an activation, making false alarms due to animals, birds, and other common nuisances a thing of the past.