Lighting Control FAQ

Term

Description

Comments

Movement Detection

A movement detector is a device that contains an electronic sensor that quantifies movement within the field of view.  An integral timer is used to keep the light on for a preset time period (generally 20 minutes) after the last detection.

Suitable for use in circulation areas such as corridors. Should not be used in areas of sedentary sitting

Presence Detection

A Presence Detector is a device that contains a sensitive electronic sensor that quantifies presence within the field of view.  An integral timer is used to keep the light on for a preset time period (generally 20 minutes) after the last detection.

Suitable for use in all areas especially where movement is at a minimum 

Absence Detection

Absence Detection is a technique whereby a switch is used to switch the light on and start the Presence Detector enabling the area to be occupied without the lights automatically switching on. This switch can also switch the light off. 

Suitable for use in cellular offices, open plan offices, meeting rooms etc. Additional energy savings will made over presence detection

PIR

A Passive infra Red (PIR) is a sensor that measures infrared  light radiating from objects in its field of view. Apparent movement motion is detected when an infrared source with one temperature, such as a person passes in front of an infra source with another temperature such as the background

The most effective of the sensor technology when designed and installed correctly

Microwave Sensor

A Microwave Sensor detects the frequency shift between a transmitted object and a received signal reflected back from a moving object within the field of view of the unit

These sensors are ideally suited to long corridors away from external windows. Not as reliable as PIR technology and can be a source of ‘nuisance tripping’

Light Sensor

A photoelectric device that provides an output relating to brightness measured. Used to determine the amount of artificial light needed to illuminate an area

Both analogue (resistive) and digital sensors are available. Digital is a superior technology providing both accuracy and stability

Light Harvesting / Constant Daylight

A technique of measuring the current light level and increasing/decreasing the artificial light output to maintain a constant light level

Best comparison is that of a heating thermostat. Energy savings are typically above 50% and is suitable for anywhere where natural light exists 

Daylight Linking

A technique of measuring the current light level and calculating whether to inhibit the artificial light from switching on or once on automatically switching it off.

One of the most common techniques used but only suitable were high natural levels of light occur, i.e. above 1500 lux

Offset Dimming

A technique of using a single light sensor to provide multiple light levels

If a light adjacent to window can be dimmed to say 70% then the next row in could realistically be dimmed by 40% and the next row by 10%. All from one sensor

White Board

A teaching / presentation wall that requires a separate lighting circuit that switches on with the main lights but has a separate switch to switch them off during teaching / presenting 

A requirement in all modern classrooms.

Corridor Hold

A technique of ensuring pre-selected lights remain on whilst other adjacent areas are occupied

This is normally used in open plan offices to provide a ‘notional corridor’  when occupancy is low

Two Stage Timeout

When a sensor times out the lights will dim to a preset level for a second period of time. During this period if the sensor detects movement the lights will return to full output and the cycle will restart.

This is most effective when used in corridors allowing for a constant low level of light at all times (such as a hotel) and only at full light when occupied.

Profiles

A technique to simplify configuring the Intelligent Marshaling Boxes. Different profiles can be selected to alter the modules configuration automatically

For example a profile can easily be selected for a classroom, corridor, WC block etc.

Zoned Control

A group of lights being controlled as a single group

Timed Control

When lights are preset to switch on and off from a time source

The least energy efficient technique and used less 

Lighting Control Module (LCM)

A module containing inputs and outputs allowing for the connection of switches, sensors, lights etc that is networked to other devices via bus wire and commissioned / re-commissioned via laptop etc.

A system that required commissioning and re-commissioning when changes are required

Marshaling Box

A module containing 230VAC inputs and outputs allowing for the connection of switches. sensors and lights. Internally pre-wired 230VAC circuits to allow a modular installation

A junction box allowing an easier/quicker installation but all inputs are 230VAC  

Intelligent Marshaling Box

A module containing SELV inputs and 230VAC outputs with the intelligence and functionality of a Lighting Control Module without the cost and complications

The advantage of a marshaling box with the functions of a Lighting Control Module. No commissioning is required due to the technique  

KNX

KNX is a standard (EN50090, ISO/IEC 14543) OSI based network communication protocol for intelligent buildings

should be used when the building services are to be fully integrated

Lonworks

Lonworks is a networking platform specifically created for the control of Lighting and Heating, Ventilation and Air Conditioning within buildings

More common in mechanical control and not common in lighting controls

BACnet

The BACnet protocol provides mechanisms for computerised building automation products to exchange information 

Usually used to interface different protocols together, i.e KNX and Lonworks

DALI

Digital Addressable Lighting Interface (DALI) is a standard for addressing and controlling lighting ballasts whereby the ballasts are programmed to respond to other DALI devices to switch and dim as required.

The most complicated technique to control lights and should only be used when a fully integrated system is required. Costly to maintain 

DSI

Digital Signal Interface (DSI) is a protocol for digitally controlling lighting ballasts developed by Tridonic 

Good reliable and simple digital switching and dimming but on available from Tridonic

Broadcast DALI

A broadcast technique that eliminates the need need to individually program ballasts

Like DSI but available from a large number of manufacturers

1-10V

1-10V is one of the oldest techniques for dimming a fluorescent light whereby a DC control pair of wires will vary between 0 - 10V (0 - 100% output)

Out of date and not as accurate as the later digital technologies.