Sometimes we like to exercise our options. We don't always do what is expected of us, and we like to try out different things to see if they might work to our advantage. Installers have that opportunity with the new active microwave beam device from Takex.
What our experts say…
Takex, formerly known as Pulnix, has produced security sensors and industrial automation sensor applications since 1982. The Japanese company is based in Kyoto and manufactures as the Takenaka Engineering Group. This new intruder alarm detection device, the MW50, has been available in the UK for around six months and provides an additional method for installers seeking a barrier protection solution using a separated transmitter and receiver system - a role normally filled by the active infrared beam.
The unit is readily available through the usual distributors (we were quoted a trade price of £186.00 + VAT) and though there is no European CE mark to be found on literature, packaging or product, Takex does provide a very healthy five year guarantee.
Construction & design
The Takex MW50 comprises two externally rated parts, the transmitter and the receiver. They are unmarked and so look identical with their familiar wine red translucent cases, in the style of the company's active infrared beams.
Both the unit and the front cover are each constructed from a rigid polycarbonate plastic , and they are secured to the mounting surface using a stainless steel back plate. The design is inoffensive and the relatively small size and smooth finish means the system would not look out of place if it were wall mounted in a domestic environment.
We were not provided with an IP rating for weather intrusion, but the internal workings look to be suitably watertight provided each unit is vertically mounted using the supplied rubber grommets in the cable entry holes.
The internal optics can be horizontally rotated through 180 degrees, which allows the beam to protect the surface to which they are face fixed, for instance located on either side of an external window. Vertical adjustment of the beam direction is also included, so the transmitter and receiver do not need to be fixed at the same height to work effectively.
Takex has not, this time, included the usual audible onboard piezo sounder as an aid to aligning the microwave chamber inside each end of the beam. On the MW50 this is achieved by using a digital multimeter (not supplied) during the initial set up at the receiving end to take a voltage reading. A figure of 1.8v or above is acceptable for stable operation.
The transmitter additionally has an onboard green LED to show the correct presence of a low voltage supply, and the receiver has an onboard red LED to show the relay changeover status. Due to the pattern of the microwave beam - best described as a cigar shape - installers will need to ensure that the equipment is intelligently sited in order to prevent false alarms due to movement of material close and parallel to the beam path.
Both the receiver and the transmitter will operate successfully at any voltage between 12v and 30v DC and it is worth noting that separate PSUs can be used locally to power each end of the beam - so the power supply does not need to be common to both transmitter and receiver.
A single form C output relay is provided at the receiver to give either normally open or normally closed operation.
Performance
The unit was found to work very well within the design parameters. An external range of 50m is easily achievable when correctly aligned. In fact a far greater distance is achievable in situations where there are hard reflective surfaces running adjacent and parallel to the electromagnetic beam.
This is because the electromagnetic energy is 'bounced' alongside the direction of travel creating a gun barrel effect, concentrating the energy into the receiver. The opposite is true when used externally, where the electromagnetic energy rapidly dissipates into the atmosphere, thus diminishing the effective operating range.
Takex's MW50 active microwave beam does exactly what it says on the tin
The cigar shape detection pattern, characteristic of microwave technology, could be better, and effectively only gives around 1.5m in width at the widest point, midway between transmitter and receiver. This widening of the detection pattern becomes more pronounced as the transmitter and receiver are moved further apart.
And though it is true to say that at each end of the beam path the detection pattern is very similar to that of an infrared beam and offers very little volumetric coverage at all, one certain improvement when compared with an infrared beam is the capacity to detect movement longitudinally along the path of the beam. This is due to the nature of microwave sensor technology which uses a 'Doppler effect' to detect changes in microwave frequency arriving at the receiver end.
The current consumption was found to be much lower than that specified by the manufacturer, at 30mA per unit on standby, dropping to around 15 mA at the receiver end during an alarm condition.
Technical literature & backup
We called Takex UK during office hours with some technical questions. The telephone number is a normally priced landline accessed through the Takex switchboard in Basingstoke, Hampshire. The technician was happy to have a fairly lengthy conversation about microwave technology in general, and demonstrated admirable knowledge and patience.
The installation instructions are contained on four sides of A4 paper, mostly in the form of diagrammatic explanations. The booklet is refreshingly in English language only, which means that information is quick and easy to find, and comprises everything necessary, including descriptions of installation precautions, troubleshooting and an electrical/physical specification. It is probably true to say that installers experienced in using active infrared beams will not need to take more than the briefest glance at the booklet.
What the manufacturer says ...
With the launch of the new MW50, Takex is proud to announce its latest addition to the professionals' choice of perimeter protection products.
The MW50 is a 50m active point-to-point microwave designed to complement the intelligent quad beams already available.
With two frequencies available, the MW50 (L/H) allows stacking or crossing of two units without problems. Designed for use where beams may be impractical due to environmental issues, or specifications call for specific use of microwave detection, the MW50 offers a realistically priced solution.
Based upon the designs of the beams, the MW50 offers 180 deg horizontal rotation within the housing and 20 deg vertical adjustment.
The MW50 is especially adept at coping with heavy fog, mist, rain, snow and frost conditions, offering the perfect alternative or addition to the active beams.
There is also the option of a combination unit, COMIN50HF, which offers both microwave and active infrared within one housing.
The MW50 offers N/O and N/C outputs, and a variable detection time for bespoke setup, and is also supplied with pole mount brackets and the option of rear pole covers to finish the job in a professional manner.
Overall assessment
Active detection beams offer a limited form of trap type protection, but they still maintain an important position in the intruder alarm market place. The degree of protection they offer will always be limited – essentially a beam of detection – but this is paradoxically their strength, and certainly when used externally, the transmitter and receiver based technology of an active electromagnetic beam has the advantage of greater precision over the more indiscriminate splatter effect of a volumetric device, such as the passive infrared movement detector.
The MW50 does exactly what it says on the tin - it is a microwave sensor with a 50 metre range. Its shortcomings include an inability to tweak the detection pattern to make the cigar shape fatter or thinner, and a lack of range adjustment to prevent the receiver from being bombarded with too much microwave energy when the transmitter is only a short distance away. But hey, what would you expect for £186?
On the plus side, the MW50 does give reasonable volumetric coverage at much the same price as an equivalent 'quad' type active infrared beam. It is also very easy to install and set up, and comes with a manufacturer's pedigree and a warranty that is hard to beat. Could be a winner.
Source
Security Installer
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