Ex-Or advances the art of controlling lighting
Ex-Or’s LightSpot HD range of lighting-control sensors is designed to provide a versatile and customisable system that can stand alone or interact with a BMS. The shape and area of the zone covered can be adjusted using clip-on lens masks that do not detract from the aesthetics of the sensors and by tilting the sensors. There are various approaches to presence and absence detection to address operational issues — about which more below. Artificial lighting can also be controlled according to available daylight.
There are some 80 variations of controls and sensors to cover applications such as office, warehouses with mid-bay and high-bay racking up to 16 m high, and factories. There are also sensors with IP55 ratings.
Project engineer Simon Bunting tells us that many of the new features, especially the approaches to presence and absence detection, have been developed in response to feedback from customers.
Each sensor has 155 specially developed lenses to provide micro (for smaller movements such as at a desk) and macro coverage of the area. The micro lenses can cover a diameter of up to 7 m, with the macro lenses adding a further 1.5 m all round.
A sensor does not need to be in the centre of the area covered; the area covered can be offset by tilting the lens.
Masks can be used to remove the macro detection zone, to create a virtual corridor or to block off one corner of a room.
While absence detection is more effective at reducing energy consumption than presence detection, various issues can detract from it being used.
With presence detection, lights are switched on automatically when someone enters the controlled area and switched off when they leave.
With absence detection, lights are switched on manually and turned off automatically or manually. One of the biggest problems with absence detection is lights being switched off automatically while someone is in the area. The lights then have to be turned on manually — which at best is a nuisance and which could be dangerous if it is dark.
LightSpot HD addresses this problem by having auto-absence recovery (essentially presence detection) for a presettable period. In addition, absence detection can be offered when it is light and presence detection when it is dark, with darkness being definable in 10 lx steps from 10 to 150 lx. The system can also be set so that lights cannot be turned off manually when it is dark.
Simon Bunting says, ‘We know that we have struck a chord with this approach to absence recovery by eliminating the problems of absence detection while still achieving its energy savings.’
Small networks of up to four sensors can be created to cover larger areas. The QuickLink system enables each sensor to act independently or as an integral part of the network. Sensors are linked using a 2-wire low-voltage connection, and data on occupancy and light levels can be shared among them.
Setting up and controlling LightSpot HD is achieved using Ex-Or’s third generation of hand-held controller, which also give access to the logging capabilities of sensors.
Once a sensor has been configured, its settings can be copied to the controller and ’pasted’ into other controllers. Sensors can log events such as switching lighting on and off and movement for 30 days, and this information can be downloaded.
That logging capability makes it possible to install sensors that do not actually control lighting to assess how much energy could be saved if the lighting were controlled. Simon Bunting suggests that controls alone would achieve a payback of one to two years.
