Sontay pushes the art of wireless control forward
If a wireless sensor costs up to five times as much as its wired equivalent, is there much point considering the use of wireless devices as part of a building-management system, or is it just simpler and cheaper to install a conventional wired system?
‘Quite the contrary,’ says Alan Braybrook, sales and marketing director with Sontay. ‘The cost of a sensor as a component is outweighed by its cost as part of a functional system.’
He puts the cost of wiring a wired sensor and commissioning it as 10 times the component cost.
In contrast, the costs associated with installing a wireless sensor from Sontay’s new SonNet range is less than the cost of the sensor.
The end result is that the installed cost of a SonNet wired sensor is nearly a third less than its wired equivalent. In addition, the work can be carried out much more quickly and with less impact on the building — an important issue with existing and heritage buildings.
There are the key benefits of wireless sensors as part of a building-management system, but the industry has been hesitant to install wireless systems because of reliability. With its SonNet range, Sontay has made full use of developing technologies to achieve reliability and long battery life for sensors — in excess of five years. The system uses the licence-free 2.4 GHz waveband.
Significantly, even before installation work commences, it is possible to demonstrate that the system will work. Sontay’s Site Survey Kit enables the various components of a system (sensors, routers and 20-channel receiver that connects to a building-management system) to be set up and tested in situ; 40 channels can be provided with an optional 20-way daughter board. The setting-up device will produce a full report of signal strengths, eliminating guesswork.
To ensure continuing reliability, A SonNet system will re-establish its communications network if problems develop. Unlike existing point-to-point wireless systems, if a sensor detects a problem with its signal getting through, it will automatically reroute to find the strongest path available to the receiver.
The SonNet system has been used by systems integrator AES Control System to retrofit HVAC controls at the head office of the Bedford Pilgrims Housing Association in Bedford. This 4-storey office block dates back to the 1980s and has a prominent glass facade, leading to problems with controlling the internal temperature. A controls upgrade was identified a being capable of bringing significant improvement to the comfort of the hundred occupants of the building.
Dave Redmond of AES explains, ‘We would have faced difficulty installing cables to sensors in an occupied 4-storey office block due to the size of the building and the amount of disruption this would present to the office staff in a highly populated call-centre-type environment. The wireless option helped us overcome these problems.’
Trevor Palmer, Sontay’s managing director, summarises the result of the company’s investment: ‘As a reliable, low-total-installed-cost alternative to wired temperature and humidity sensors, SonNet broadens the market potential for integrators, especially in retrofitting control systems.’