Smart guide to sensors 11.03.13

Smart Guide to Lighting Sensors

18/03/2013 www.ukenergypartners.co.uk

UKEP Smart Guide to…

Lighting Sensors – what do you need to know?

• Types of Detection

– How they work

– Where & where not to use them

• Terminology

– Presence/Absence

– Photocells

• What to expect from a survey

• Next Steps


Movement Detection

• Two Categories:– Passive– Active

• Different Technologies:• Active

– Ultrasonic– Microwave– Active Infra Red (Beam Break)

• Passive– Passive Infra Red (PIR)


Ultrasonic

• Ultrasonic– “Radar” technology to monitor the controlled space that will respond to small

movements

– Emits ultrasound and looks for reflections

– Medium range

– Range dependent upon activity

• Will see small movements close up

• Requires more movement at longer distance


Ultrasonic


For

• Relatively low cost

• High quality presence detection

• Poor definition of detection area

• Doesn’t see through glass or thin office partitions

Against

• Poor for low incidence of false detections

• Affected by air movement

• Not good in electrically noisy environment

• Potential problem of interaction between similar units

Microwave


• Microwave– Active presence detection – Sends out microwaves, looks at reflected signals– Sensitive to small body movements– Must be mounted on rigid/stable surface– Will “see” through glass/partitions– Medium/long range

• 20/30/60 metres

Microwave


For

• Relatively low cost

• Very high quality presence detection

• Covers large areas – up to 60x60 metres

• No potential for unwanted interaction with other equipment

Against

• Poor for low incidence of false detections

• Not affected by air movement, but affected by moving metal

• Poor definition of detection area

• Sees through glass or thin office partitions

• Potential problem of interaction between similar units –frequency of operation (10.7 GHz)

PIR


• Passive Infra Red– Operates on a combination of movement & heat

– Generally smaller areas

– Around 6 metres conical detection pattern

– Exception - specific Hi-Bay applications

PIR


Pro

• Low cost

• Compact

• Easy to implement

• Reasonable quality presence detection

• The best for low incidence of false detections

• Works well in electrically noisy environment

• Very good definition of detection area

• Doesn’t see through glass or thin office partitions

• No unwanted interaction between similar units

Con

• Smaller area of coverage with exceptions

Comparing Modes of Detection


Technology

PIR Ultrasonic Microwave

Cost Low Medium Medium

Detection Good Very good Excellent

No Detection Excellent Adequate Adequate

Precision Excellent Adequate Good

Implementation

(engineering)

Easy Medium Medium

Common Terminology


• Presence

• Absence

• Passive Photocell

• Active Photocell

• Regulating Photocell

Common Terminology


Presence or Absence

• What are we detecting?Presence or Absence

• In truth, neither – sensors are really detecting movement but these are the terms used.

• Presence Detector– Auto ON, Auto OFF - sensor will control lights

automatically.

• Absence Detector (also referred to as Semi Automatic)– Manual ON, Auto OFF – sensor requires manual

switch to initiate controls.

Common Terminology


Photocells – daylight-sensitive cells built into your sensors

• Passive Photocell– Holds lights off in bright ambient conditions– Will not turn lighting off if light level rises whilst area is

occupied

• Active Photocell– Switches lights on and off according to ambient levels– Whether there is presence or not– Passing Cloud Timer

• To prevent oscillation of lighting• Fixed at the OFF delay time or 20 mins. maximum

• Regulating Photocell– Adjusts light output according to ambient level (dimming)– DSI, DALI or 1-10v (Analogue) versions

Next Steps


• We hope this gives you an idea of how best to serve your site. The best sensor designs are the most thorough – use expert, impartial advice in planning and design.

• Energy saving varies according to area and occupancy, but typically ranges between 40 and 60%.

• If you want to know more, email UK Energy Partners at [email protected]

• Or call us on 0844 318 3000 now.

mailto:[email protected]

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Smart guide to sensors 11.03.13