Lighting Control Systems

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Lighting Control

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TABLE OF CONTENT

page

1 Designing a lighting control system 3

1.1 System design 4

1.2 Step 1 - Application needs 5

1.3 Step 2 Appropriate control strategies - 5

1.4 Step 3 – Selecting control products 7

1.5 Step 4 - Layout, specifi cation & documentation 10

2 Lighting 11

2.1 Color temperature 12

2.2 Comparission Fluorescent vs Incandescent 13

2.3 Energy effi cency lumen/watt 14

2.4 Lumen 14

2.5 Lux 14

2.6 Illuminance 15

3 Lamps and Loads 16

3.1 Light sources 17

3.2 Control gear 20

3.3 Dimming Principles 21

3.4 Special requirement at switching and dimming 22

4 Applications 24

4.1 Introduction 25

4.2 Occupancy Control 27

4.3 Scheduling 30

4.4 Constant LightControl 33

4.5 Dimming Control 36

4.6 Shutter Control 39

5 Application practice 41

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Lighting design and engineering professionals are facing the challenge and

demand for energy conservation in buildings. Mandatory energy codes

requires lighting control in new buildings

Effective lighting control saves energy, reduces operating costs, and helps

maintain a safe and productive environment for occupants. Well designed and

installed, lighting control also provides convenience for occupants and

enhances productivity.

Designing an optimal lighting control system may often incorporate several

types of controls as well as different control strategies to achieve an integrated,

total-facility approach

1 Designing a lighting control system

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1.1 System design

The design process for a lighting control project includes:

1. Applications needed

2. Control strategies to be used

3. Which are the appropriate product(s) for the application

4. Layout, specifi cation and documentation of the lighting controls

5. Guidelines of how install and commission the lighting controls

What application

Control strategy

Product selectionDocumentation

Installation

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1.2 Step 1 - Application needs

1.3 Step 2 Appropriate control strategies -

The starting point for any project is the need to understand the motivation,

reasons, and characteristics of the application involved.

Energy code compliance requirements

With energy code compliance becoming mandatory, this is often the driver behind

the need for lighting control. Most common requirements are:

Individual space control

Automatic shut off

Energy conservation

Outdoor light control

Energy conservation

Many building owners and facility managers want to reduce operating costs by

minimizing energy expenses as much as possible while ensuring the comfort and

safety of facility occupants.

Occupant convenience and preference

Ensuring that occupants have a convenient and accessible personal control over

local lighting which enhances occupant satisfaction and productivity.

Safety and security

Ensuring that facility lighting always is safe and secure for occupants and visitors.

Maintenance and administration

Providing the facilities management staff with the necessary controls and tools to

effectively manage the facility.

At this point, designers should select the appropriate control strategy that best

fi ts with the application’s needs. Since most buildings contain numerous spaces

housing different activities, multiple strategies may be desirable to meet the

specifi c needs of all the different space types.

Some applications may need only a single product implementing a simple

strategy, such as a time switch providing timed ON/OFF control. In other

applications, designers may combine several control methods. For instance, offi ce

spaces may benefi t from time-based ON/OFF control during regular work hours,

supplemented by occupancy-based control after hours.

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Step 2 Appropriate control strategies - (con’t)

In the case of commercial or public buildings a part of the applications utilizes

common components in a building automation system for controlling different

functionalities

These basic control strategies can be implemented singly or combined as

appropriate for the application:

Automated shutoff

A basic requirement for lighting energy effi ciency and energy code compliance,

turning lighting off when it is not needed (non occupancy) is a primary control

strategy. The same devices used to shut lighting off may also provide users with

the ability to turn lighting on. This information could also be used to control other

devices controlled by the HVAC system.

Individual space control

This is usually a base requirement for energy code compliance. Usually control

devices must be located so that lighting controlled is visible from the devices

installed location. If lighting is not visible from that location, the device usually

must have some type of annunciation (i.e., pilot light) that indicates lighting

status (ON/OFF).

Reduced level lighting control (also referred to as bi-level switching)

When it is desirable or required by energy codes, spaces may contain controls to

manually reduce lighting levels uniformly. This can be accomplished by turning off

individual lamps within luminaries, turning off alternating luminaries, or dimming

all luminaries to reduced levels.

Exterior lighting control

Ensuring lighting is on whenever it is dark outside and off when there is suffi cient

daylight or the area is no longer occupied. Exterior lighting control is generally

broken down into two primary categories of lighting:

1. Exterior security night lights = all lighting that turns on at dusk and remains

on all night until dawn when suffi cient daylight returns.

2. General exterior lighting = lighting that is on when it is dark and turns off

subsequently during the night time when the area is no longer occupied or in use.

Daylighting control

Reducing or eliminating electric lighting when there is an adequate contribution of

daylight within a space.

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1.4 Step 3 – Selecting control products

These guidelines can help designers match up the best product for

achieving a specifi c control strategy.

Control Strategy: Automated shutoff

Products for implementing this strategy are occupancy sensors, movement

detectors time switches and schedulers.

Occupancy sensors

detects space vacancy and light level for automated shutoff.

Movement detectors

detecting movement for automated shutoff.

Recommended applications:

• Locations with intermittent occupancy and activity

• Private offi ces, conference rooms, restrooms, break rooms, some open

offi ces

Scheduler

controls relays to turn lighting off according to a programmed schedule.


• Applications where it is desirable to keep lighting on during hours of

normal business or space usage.

• Lobbies, corridors, public spaces, retail sales fl oor, some open offi ces.

Time switch

Wall switches turn on manually and then turn off automatically after a preset

interval.


• Spaces with infrequent activities or where occupancy sensors may not

be able to perform consistently

• Store rooms, mechanical and electrical rooms, supply closets, janitorial

spaces.

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Step 3 – Selecting control products con’t

Control Strategy: Individual Space control

Suitable products for implementing this strategy are manual switches and

occupancy sensors.

Manual switches

These are available in a variety of types and technologies:

• Line voltage switches control power directly to fi xtures.

• Low voltage or bus switches, signal occupancy sensors

• Wall switch occupancy sensors (P.I.R.) combine occupancy based shutoff with

manual ON/OFF and preset control

• Time switch combines timed shutoff with manual ON/OFF

Manual switches work in conjunction with shutoff, day lighting and other control

strategies.

Day lighting control

Appropriate products for implementing this strategy are automatic switching

controllers and automatic dimming controls.

A photocell component measures daylight levels, transmits the data to the control

component, which then switches or dims lighting.

Automatic switching controllers

Automatic dimming controllers dimmable ballasts and automatic dimming day

lighting controls


• Interior building spaces with architectural design elements (i.e., windows,

skylights, etc.) that permit adequate daylight.

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Step 3 – Selecting control products con’t

Exterior lighting control

Products for implementing this strategy are relay panels with

astronomic clock and/or photocells, and occupancy sensors.

Relay panels controlled by photocells

There are a number of different ways these devices may be used:

• Photocell ON/OFF control:

Use an exterior photocell with a lighting control panel for automated ON/OFF of

exterior lighting at dusk and dawn. Photocell automatically adjusts for seasonal

sunrise/sunset changes as well as transient changes in light conditions

• Astronomic clock ON/OFF control:

Panel-based astronomic clocks turn exterior lighting ON/OFF based on calculated

seasonal sunrise/sunset changes.

• Photocell ON/OFF + time scheduled control:

Combining panel-based time scheduling with the light/dark sensing capability of a

photocell allows effi cient exterior lighting control.

• Astronomic ON/OFF + time scheduled control:

Combining panel-based time scheduling with the sunrise/sunset prediction of

astronomic control enables automatic ON at calculated sunset with OFF later

when premises are vacated.

Occupancy sensor + photocell control:

Combining occupancy-based and photosensitive control turns lighting on when

occupancy is detected and it is dark.


• All building, parking lot, site, signage, walkway exterior lighting.

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1.5 Step 4 - Layout, specifi cation & documentation

Once the product selection is complete, the designer will lay out the control

devices on the general lighting plan drawings.

Different lighting control products require specifi c design details. For instance,

with occupancy sensors, plans should include placement location of individual

sensors as well as the coverage area of each. For switches, plans should indicate

location and control assignment. For day lighting controls, plans should include

photocell placement as well as the desired lux settings for each covered area.

When lighting control panels are used, designers should prepare riser diagrams

and control schedules. This documentation will assist the designer in preparing a

specifi cation that unifi es the entire plan.

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We see things every day, from the moment we get up in the morning

until we go to sleep at night. We look at everything around us using

light. We appreciate fi ne oil paintings, swirling computer graphics,

gorgeous sunsets. But did you ever stop to think that what we see is

light-- light that somehow left objects far or near and reached our eyes.

Light is all our eyes can really see.

The other way that we encounter light is in devices that produce light --

incandescent bulbs, fl uorescent tubes, lasers, lightning bugs, the

sun. Each one uses a different technique to generate light.

Lighting includes both artifi cial light sources such as lamps and

natural illumination of interiors from daylight. Lighting represents a

major component of energy consumption, accounting for a signifi cant

part of all energy consumed worldwide. Proper lighting can enhance

task performance or aesthetics, while there can be energy wastage and

adverse health effects of lighting. Indoor lighting is a form of fi xture or

furnishing, and a key part of interior design. Lighting can also be an

intrinsic component of landscaping.

2 Lighting

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Some common examples.

1700 K: Match fl ame •

1850 K: Candle •

2800 K: Tungsten lamp (incandescent lightbulb) •

3350 K: Studio “CP” light •

3400 K: Studio lamps, photofl oods, etc... •

4100 K: Moonlight •

5000 K: Daylight •

5500 K: Average daylight, electronic fl ash (can vary between •

manufacturers)

5770 K: Effective sun temperature •

6420 K: Xenon arc lamp •

6500 K: Daylight° •

9300 K: TV screen (analog) •

Color temperature is a characteristic of visible light that has important

applications in photography, videography, publishing and other fi elds. The

color temperature of a light source is determined by comparing its hue with

a theoretical, heated black-body radiator. The Kelvin temperature at which

the heated black-body radiator matches the hue of the light source is that

source’s color temperature, and it is directly related to Planck’s law.

2.1 Color temperature

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2.2 Comparission Fluorescent vs Incandescent

15x1000 h 15000 h

Life span

Effi iciency

100 % 20 %

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2.3 Energy effi cency lumen/watt

The lumen (symbol: lm) is the SI unit of luminous fl ux, a measure of the

perceived power of light

The lux (symbol: lx) is the SI unit of illuminance. It is used in photometry

as a measure of the intensity of light, with wavelengths weighted according

to the luminosity function, a standardized model of human brightness

perception.

Lux versus lumen

The difference between the lux and the lumen is that the lux takes into

account the area over which the luminous fl ux is spread. 1000 lumens,

concentrated into an area of one square metre, lights up that square metre

with an illuminance of 1000 lux. The same 1000 lumens, spread out over ten

square metres, produces a dimmer illuminance of only 100 lux.

Achieving an illuminance of 500 lux might be possible in a home kitchen with

a single fl uorescent light fi xture with an output of 12000 lumens. To light

a factory fl oor with dozens of times the area of the kitchen would require

dozens of such fi xtures. Thus, lighting a larger area to the same level of lux

requires a greater number of lumens.

2.4 Lumen

2.5 Lux

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Illumenance is measured in lux, one lux is one lumen per square meter.

Light Level or Illuminance, is the amount of light measured in a plane. The work

plane is where the most important tasks in the room or

space are performed.

The outdoor light level is approximately 10,000 lux on a clear day.

In the building, in the area closest to windows, the light level may be reduced

to approximately 1,000 lux. In the middle area its may be as low as 25 - 50 lux.

Additional lighting equipment is often necessary to compensate the low levels.

Earlier it was common with light levels in the range 100 - 300 lux for normal

activities. Today the light level is more common in the range

500 - 1000 lux - depending on activity. For precision and detailed works, the

light level may even approach 1500 - 2000 lux.

The table below is a guidance for recommended light level in

different work spaces:

2.6 Illuminance

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3 Lamps and Loads

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The incandescent light bulb or incandescent lamp is a source of

artifi cial light that works by incandescence. An electrical current passes through a

thin fi lament, heating it and causing it to become excited,

releasing thermally equilibrated photons in the process. The enclosing

glass bulb prevents the oxygen in air from reaching the hot fi lament,

which otherwise would be destroyed rapidly by oxidation.

A benefi t of the incandescent bulbs is that they can be produced for a

wide range of voltages, from just a few volts up to several hundred

volts. Because of their relatively poor luminous effi cacy, incandescent

light bulbs are gradually being replaced in many applications by

(compact) fl uorescent lights, high-intensity discharge lamps, LEDs, and

other devices. Compact fl uorescent bulbs are particularly easy to use,

because they screw into regular incandescent bulb sockets, consume

far less electricity and produce less heat, produce light spectra that are

at least acceptable for consumer purposes, and produce a many-fold

cost savings over their lifetime.

Incandescent lamp

Halogen lampHalogen lamps are high pressure, incandescent lamps that contain halogen

gases such as iodine and bromine that allow fi laments to work at higher

temperatures and higher effi ciencies. Halogen lamps consist of a tungsten

fi lament inside a quartz envelope that is fi lled with halogen gas. In halogen

lamps, the quartz envelope is closer to the fi lament than the glass used in

conventional light bulbs. Heating the fi lament to a high temperature causes

the tungsten atoms to evaporate and combine with the halogen gas. These

heavier molecules are then deposited back on the fi lament surface. This

recycling process increases the life of the tungsten fi lament and enables the

halogen lamp to produce more light per units of energy.

3.1 Light sources

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Compact fl uorescent lamp (CFL) is a type of lamp (light bulb) designed

to fi t into roughly the same space as an incandescent lamp, but with the

advantages of a fl uorescent lamp. Many CFLs can directly replace an existing

incandescent lamp.

Compared to incandescent lamps of the same luminous fl ux, CFLs have a

longer rated life and use less energy.

Although CFLs do radiate a different spectrum of light than incandescent

lamps, recent technological advances have reduced that difference

dramatically. The light emitted by the best soft white CFLs available today is

similar in quality to standard bulbs.

Modern CFLs typically have a life span of between 8,000 and 15,000 hours,

whereas incandescent lamps are usually manufactured to have a life span of

750 hours or 1000 hours.For a given light output, CFLs use between one-fi fth

and one-quarter of the power of an equivalent incandescent lamp, thereby

saving signifi cant amounts of energy and reducing the need for electrical

generation. For industrialized countries, lighting makes up about one fi fth of

electricity consumption, so there are potentially signifi cant benefi ts.

Incandescent lamps are less effi cient than CFLs because incandescent lamps

convert approximately 90% of the energy they consume into heat (compared

to 30% for a CFL).

Compact

fl uorescent lamp

Fluorescent tubeA fl uorescent tube is a gas-discharge lamp that uses electricity to excite

mercury vapor in argon or neon gas, resulting in a plasma that produces

short-wave ultraviolet light. This light then causes a phosphor to fl uoresce,

producing visible light.

Unlike incandescent lamps, fl uorescent lamps always require a ballast to

regulate the fl ow of power through the lamp. In common tube fi xtures

(typically 4 ft (120 cm) or 8 ft (240 cm) in length), the ballast is enclosed in

the fi xture. Compact fl uorescent light bulbs may have a conventional ballast

located in the fi xture or they may have ballasts integrated in the bulbs,

allowing them to be used in lampholders normally used for incandescent

lamps.

Compact fl uorescents may fail to operate at low temperatures. Light output

drops at low temperatures, and they may not light at all below zero

degrees C0 They also suffer shortened life when switched on and off

frequently. Incandescent bulbs operate well with no loss of brightness at

extremely low or high temperatures and can better withstand frequent

turning on and off, as in security light applications. Manufacturers of compact

fl uorescents warn against using ordinary CFLs to replace incandescent bulbs

in enclosed fi xtures or those which are controlled by dimmers. Dimming

fl uorescent lamps requires lamp ballasts designed for dimming.

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Metal halide lampMetal halide lamps, a member of the high-intensity discharge (HID) family

of lamps, produce high light output for their size, making them a compact,

powerful, and effi cient light source. Originally created in the late 1960’s for

industrial use, metal halide lamps are now available in numerous sizes and

confi gurations for commercial and residential applications. Like most HID

lamps, metal halide lamps operate under high pressure and temperature, and

require special fi xtures to operate safely. Metal halide lamps require electrical

ballasts to regulate the arc current fl ow and deliver the proper voltage to the

arc. Probe start metal halide bulbs contain a special ‘starting’ electrode within

the lamp to initiate the arc when the lamp is fi rst lit (which generates a slight

fl icker when the lamp is fi rst turned on). Pulse start metal halide lamps do not

require a starting electrode, and instead use a special starting circuit referred

to as an ignitor to generate a high-voltage pulse to the operating electrodes. A

few electronic ballasts are now available for metal halide lamps..

They are also considered a “point” light source, so refl ective luminaires are

often required to concentrate the light for purposes of the lighting application.

Metal-halide lamps are used both for general industrial purposes, and for

very specifi c applications which require specifi c UV or blue-frequency light.

They are used for indoor growing applications, because they can provide the

spectrum and temperature of light which encourage general plant growth.

They are most often used in athletic facilities.

A sodium vapor lamp is a gas discharge lamp which uses sodium in an

excited state to produce light. There are two varieties of such lamps: low

pressure and high pressure.

Low pressure / LPS / SOX

LPS Lamps (Low Pressure Sodium), also known as SOX Lamps are the

most effi cient electrically powered light source when measured for photopic

lighting conditions. — up to 200lm/W As a result they are widely used

for outdoor lighting such as street lights and security lighting where color

rendition is viewed by many to be less important. LPS lamps are available

with power ratings from 10 W up to 180 W, however length increases greatly

with wattage creating problems for designers.

High pressure / HPS / SON

High pressure sodium lamps are quite effi cient — about 100 lm/W, up to

150 lm/W, when measured for Photopic lighting conditions. They have been

widely used for outdoor lighting such as streetlights and security lighting.

Understanding the change in human color vision sensitivity from photopic

to Mesotopic and Scotopic is essential for proper planning when designing

lighting for roads.

Sodium vapor lamp

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A variation of the high pressure sodium, the White SON, introduced in

1986, has a higher pressure than the typical HPS lamp, producing a color

temperature of around 2700K, with a CRI of 85; greatly resembling the color

of incandescent light. These are often indoors in cafes and restuarants to

create a certain atmosphere. However, these lamps come at the cost of higher

purchase cost, shorter life, and lower light effi ciency.

All gas discharge lamps, including fl uorescent lamps, require a control gear

to operate. The control gear provides a high initial voltage to initiate the

discharge, then rapidly limits the lamp current to safely sustain the discharge.

Necessity for current limiting

Control gears are most commonly needed when an electrical circuit or device

presents a negative resistance to the supply. Examples of such negative-

resistance devices are gas discharge tubes and lamps. If such a device

were connected to a constant-voltage power supply, it would draw an ever-

increasing amount of current until it was destroyed or caused the power

supply to fail. To prevent this, a ballast provides a positive resistance or

reactance that limits the ultimate fl ow of current to an appropriate level.

3.2 Control gearThe main types of control gears are:

Magnetic ballast using a inductor to provide the proper starting and

operating electrical condition to power a fl ourescent lamp, neon lamp, or high

intensity discharge (HID) lamp.

The inductor has two benefi ts it’s reactance limits the power available to the

lamp with only minimal power losses in the inductor and the voltage spike

produced when current through the inductor is rapidly interrupted is used in

some circuits to fi rst strike the arc in the lamp.

The disadvantages are that it does not provide dimming possibilties for the

26 mm tubes and needs a separate starter, which when the tube fails to start

tries to restart the tube and causes an annoying blinking

Electronic ballast uses solid state electronic circuity to provide the proper

starting and operating electrical condition to power one or more fl uorescent

lamps and HID lamps. Electronic ballasts usually change the frequency

of the power from the standard mains frequency to 20,000 Hz or higher,

substantially eliminating the stroboscopic effect of fl icker (100 or 120 Hz,

twice the line frequency) associated with fl uorescent lighting. Because of the

high frequency of operation, electronic ballasts are generally smaller, lighter,

and more effi cient (and thus run cooler) than magnetic ballasts.

Electronic ballasts are often based on inverter/converter style switched-

mode power supplies, fi rst rectifying the input power and then chopping it at

a high frequency. Advanced electronic ballasts may allow dimming via pulse-

with modulation and remote control and monitoring via networks such as

LonWorks, Dali, DMX, DMX-512, DSI or simple analog control using a 0-10V

DC brightness control signal.

White SON

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Magnetic transformers are made with an iron or ferrite core and multi-

wound coil system; commonly called a coil-core transformer. These devices

transform the voltage in a predictable way using magnetic coupling.

Electronic transformers are generally made of an inverter and a smaller

transformer. Due to the design and manufacturing of electronic transformers,

the characteristics and performance can not always be predicted

Transformers

A light dimmer works by essentially chopping parts out of the AC voltage.

This allows only parts of the waveform to pass to the lamp. The brightness

of the lamp is determined by the power transferred to it, so the more the

waveform is chopped, the more it dims.

3.3 Dimming Principles

Triac and Thyristor Dimmers (leading edge)Triac or thyristor dimmer

devices operate in a very similar fashion.

The triac or thyristor is switched on at a certain phase angle and will

beautomatically switched off at the zero crossing point in each half-

wave.These dimmers are used for resistive, and inductive loads, such as

incandescent, cold cathode and low voltage (inductive) lamp sources. Note

that not all electronic transformers used for low voltagelamps are suitable for

dimming by triac or thyristor dimmers.

Transistor Dimmer (trailing edge)

A transistor based dimmer switches the supply off at a certain phase angle

and on at the next zero crossing and is commonly known as a trailing

edge dimmer. By switching the current off the possibility for voltage peaks

is eliminated.These dimmers should be used when dimming electronic

transformers (capacitive) and mains voltage (resistive) lamps.

Shaded area

lights OFF

Shaded area

lights OFF

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Fluorescent lights

dimming

Fluorescent lights

switchingA switch or relay will turn lights on or off by supplying or removing voltageto

the ballast. When controlling electronic ballasts it is standard practice to

derate the switch or relay to 75% or less. If the switch is rated at 16A, then

the connected fl uorescent load should be 12A or less. Magnetic ballast loads

may need to be derated up to 50% due to the high inductance caused by

the ballast. When fl uorescent ballast are fi rst turned on there is a large

surge of energy usage called current inrush. This current inrush can be

10 to 100 times the steady state value of a system, but only lasts for a

fraction of a second. If the total amperage of a system is 10 amps, then the

current inrush could be up to 1000 Amps. This large surge of energy can be

damaging to the relay contacts. Current inrush is only present at turn on and

can be responsible for opening fuses and tripping circuit breakers.

Fluorescent lamps can also be dimmed when used with a dimming ballast.

Not all ballasts are dimmable, but all can be switched. Digital controlled

ballast are becoming more available on the market. There are a few

different protocols from several different manufacturers. DALI or Digitally

Addressable Lighting Interface, DSI, LON, DMX512, and KNX are a few of

the digital control methods. Some devices can only be dimmed to a certain

level and also require a minimum turn on level. The minimum turn on level

is determined by the ballast. Turning it on or dimming below this level can

cause fl ickering and premature lamp failure. Consult the manufacturer

to determine the dimming performance of any ballast used in a dimming

system.

It is not recommended to mix different loads on a dimmer like incandescent

with magnetic or electronic ballasts. There is an increased possibility of bad

performance, along with more complicated trouble shooting. There should

be a positive disconnection from power when the dimmer is off to prevent

a voltage leaking to the ballast. Ballast manufacturers recommend this

practice for maximum safety. It is recommended that a circuit with ballasts

not exceed 80% capacity. It is standard practice to derate the dimmer to

80% or less. If the dimmer is rated at 500W, then the connected fl uorescent

load should be 400W or less.

3.4 Special requirement at switching and dimming

Universal dimmers

Adaptive Dimmers solves all the load compatibility problems inherent in loads

controlled by both triac and transistor dimmers.In universal dimmer, both

the voltage and the current are monitored, and this is linked into the CPU

which controls the dimmers operating parameters. When the adaptive source

controller “sees” an inductive load, it adopts a leading edge dimmingmode. In

case of overload the device is automatically switched off.

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There are two types of transformers used in lighting; magnetic and

electronic. Transformers are rated using Volts times Amps (VA) or in

total Watts, and should specify input voltage and corresponding output

voltage. A transformer rating could be 230V primary, 12V secondary,

50W capacity. The 50W refers to the load on the secondary wires. There

are three types of dimmers for transformers; standard incandescent or

phase forward, reverse phase, and universal . Standard dimmers work

well with magnetic transformers and some electronic ones. Reverse phase

or electronic low voltage dimmers work well with electronic transformers.

A universal dimmer works well with either type. The standard dimmer

is least expensive and most reliable, while the univerasal dimmer is the

most expensive and more complicated. Dimmers are de-rated when

connected to a transformer load. The dimmer must operate the lamp,

and also compensate for the current loss in the magnetic operation of

the transformer itself. Therefore, a percentage of the dimmer’s load will

be used up in the transformer process. The standard calculation adds the

Wattage of the lamp, along with 20% of the load (in Watts) to the dimmer.

Thus, a 100W lamp, connected to a transformer, will be rated at 120W to

the dimmer. That allows cooler operation of the transformer and prevents

overloading.

Transformers

Dimming

It is better to switch a transformer with a mechanical relay than a solid

state one. The solid-state relay has a bias current that leaks to the

transformer even during the ‘off’ state that can cause premature failure

of the transformer or misleading voltage measurements. . Switching

transformer loads on and off using a relay is not problematic. When

controlling electronic transformers it is standard practice to derate the

switch or relay to 75% or less. If the switch is rated at 16A, then the

connected fl uorescent load should be 12A or less.

Magnetic ballast loads may need to be derated up to 50% due to the high

inductance caused by the transformer. When electronic transformers are

fi rst turned on there is a large surge of energy usage called current inrush.

This current inrush can be 10 to 100 times the steady state value of a

system, but only lasts for a fraction of a second. If the total amperage of

a system is 10 amps, then the current inrush could be up to 1000 Amps.

This large surge of energy can be damaging to the relay contacts. Current

inrush is only present at turn on and can be responsible for opening fuses

and tripping circuit breakers.

Transformers

switching on/off

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4 Applications

Occupancy Control

Scheduling

Constant Light Control

Dali Dimming Control

Shutter Control

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4.1 IntroductionReducing the connected load (wattage) of the lighting system represents only

half of the potential for maximizing energy savings. The other half is minimizing

the use of that load through automatic controls. Automatic controls switch or dim

lighting based on time, occupancy, lighting-level strategies, or a combination of

all three. In situations where lighting may be on longer than needed, left on in

unoccupied areas, or used when suffi cient daylight exists, you should consider

installing automatic controls as a supplement or replacement for manual controls.

Automatic controls for lighting, in commercial buildings, are available in a

variety of options. Controls can switch lights on and off, or dim lights based on

input from sensors which include timers, occupancy sensors to detect motion or

infrared radiation from a person, or photosensors which operate lights or adjust

light levels based on the amount of available daylight. There are also sensors,

suitable for accessibility, that operate lighting by voice or sound. Many systems

include the option of remote control via phone, computer, or a standard remote

control.

Controls can be hard-wired or wireless. Most hard-wired controls rely on low-

voltage bus wiring for signal transmission. However, there are a few products

on the market that transmit signals over standard wiring (and therefore require

no additional wiring). Some systems are “plug and play” while other systems -

typically ones that provide the most fl exibility - require design and programming

by the installer. Central lighting control systems can be “zoned” to provide

pre-programmed lighting levels (often called “scenes”) for different situations.

Examples of modes that may be preprogrammed are use of video-beamer in

conference rooms.

A manual-on occupancy sensor is a wall switch that will allow regular on and

off switching of lights and can be used as an electronic occupancy sensor, as

well. The occupancy sensor operates on low frequency sound waves or infrared

signals that can sense movement in an area. After a prescribed time delay of six

to fi fteen minutes, dependent upon manufacturer or local preset, the sensor will

turn off the light if movement has not been detected.

26

Dimmer switches can allow one fi xture to serve several lighting functions, such

as task lighting at full ballast and decorative or safety lighting on a lower setting.

Dimming increases lamp life and saves energy - a light that is dimmed by 25%

uses about 20% less energy while lamp life is increased fourfold.

Lighting in a commercial offi ce building often accounts for at least 40% of the

total electricity used. Simply switching off lighting when it is not required results

in substantial energy savings. Regardless of the amount of automation used for

lighting control in a given application, the ability to manually override lighting is

often an important element in the overall design. =S= controls offer a variety of

choices for manual override of lighting in systems including simple low voltage

wall switches and networked button stations

Dimming is an effective tool used in lighting-system designs to reduce energy

consumption, provide appropriate light levels for tasks, increase visual comfort,

and provide aesthetic appeal. The =S= lighting control system provides dimming

functions to meet these requirements through a variety of user interfaces and

programmed functions such as simple manual control, user-saved preset lighting

scenes, automatic daylight harvesting, and load shedding. Today it is possible to

dim most popular fl uorescent lamp types and =S= controls are compatible with

virtually all available solid-state dimming ballast choices

27

4.2 Occupancy Control

Occupancy sensors provide effective lighting control for smaller areas within the

building that are occasionally utilized. They can also be used to provide automatic

override of schedules for after-hours usage by occupants or cleaning crews.

Using occupancy sensors as part of a system allows independent sensing zones

to be functionally linked or separated as appropriate based on the time of day.

The occupancy sensors may also simply be deactivated during normal business

hours and reserved for after-hours override operation. Further, when sensors are

used as part of the LON system, occupancy status can be easily shared with the

Building Automation System to direct HVAC and other non-lighting functions.

Open Offi ce Area

Scheduled Zone Control

General illumination for open offi ce areas is controlled by the system on a

zone basis. Lighting automatically comes on in the morning to greet arriving

employees, in areas where light level is suffi cient and no occupancy registered

the lights will turn off after a delay until occupancy is registered . At the end of

the workday, if no occupancy registered, lighting is automatically switched off.

The potentially harmful effects of inrush generated by switching large fl uorescent

loads is nullifi ed by the =S= control system’s zero-cross switching technology.

Manual Zone Control

Manually switching on lighting in the morning, and when no occupancy

registered, the light is switcht off maximizes energy savings and eliminates the

need to program holidays into the schedule. To prevent tampering, the switch is

disabled during normal work hours. Later in the evening, the cleaning crew uses

the same switch to turn on lighting for a programmed period of time.

Occupancy-Based Override

Occupancy sensors provide automatic override of lighting during after-hours

periods, eliminating the need for manual override by employees or the cleaning

crew. Sensor operation is automatically limited to after-hours operation by =S=

controls. Adjacent sensor zones are logically linked for simultaneous operation to

eliminate the discomfort of a lone employee working in a small pool of light.

Private Offi ce

Distributed Personal Control

Desk lamps are used and controlled by the occupant as task lighting. The general

lighting is controlled by a sensitive presence detector which covers the whole

offi ce area and will automatically shut off, or in case of dimming, dim the lighting

to a un-occupancy level. All stations for an entire fl oor share a single network

wire. Since the signals for the dimming ballasts and the local relay packs are

provided directly by the station, no additional home run wiring is required.

28

Occupancy Reporting

Energy savings in small areas like offi ces is maximized through the use of

occupancy sensors. Lighting is automatically turned off when the occupant leaves

the offi ce for an extended length of time. Since the =S= control system has

“visibility” of the occupancy status, it can be passed on to the HVAC controls via

the LonTalk protocol.

Infrequently used spaces

Occupancy sensors are ideal in infrequently used spaces like bins, toilets, and

corridors. Lighting is automatically turned on when the occupant enters the

space. Adjacent sensor zones are logically linked for simultaneous operation to

eliminate dark spots in wider areas.

About Occupancy Sensing

Occupancy-based strategies are best suited to spaces that have highly variable

and unpredictable occupancy patterns. Occupancy or motion sensors are used

to detect occupant motion, lighting the space only when it is occupied. For both

initial and sustained success in using occupancy sensors, the sensor must be able

to see the range of motion in the entire space while avoiding either on or off false

triggering. This requires proper product selection, positioning, and testing.

Occupancy sensors should fi rst be selected based on the range of body motion

expected to occur throughout the entire lighted space.

Controls for hallways, for example, need only be sensitive to a person walking

down a narrow area, while sensors for offi ces need to detect smaller upper body

motion, such as typing or reaching for a telephone. Once sensitivity and coverage

area is established, sensors are selected from two predominant technology types.

Passive infrared sensors detect the motion of heat between vertical and

horizontal fan pattern detection zones. This technology requires a direct line of

sight and is more sensitive to lateral motion, but it requires larger motion as

distance from the sensor increases. The coverage pattern and fi eld of view can

also be precisely controlled. It typically fi nds its best application in smaller spaces

with a direct line of sight, warehouses, and aisles.

29

Application description

Occupancy controlled general lighting with time based override possibilities.

Single-occupant offi ce. Primary activities are computer work, reading and

meetings.

Control needs

ON/OFF control with light level sensing. The sensor should be able to detect small

movements such as typing.

30

4.3 SchedulingTime-based lighting control provides substantial energy savings by automatically

turning off lighting after normal working hours. =S= lighting controls meet the

requirements of modern energy codes and standards, distributed systems like

=S= are ideal for meeting these requirements for larger public areas in buildings,

industrial applications, exteriors, or anywhere occupancy sensors are not

appropriate.

Open Offi ce Area

Manual Zone Control

Manually switching on lighting in the morning maximizes energy savings and

eliminates the need to program holidays into the schedule. At the end of the

workday, lighting is automatically switched off. To prevent tampering, the switch

is disabled during normal work hours. Later in the evening, the cleaning crew

uses the same switch to turn on lighting for a programmed period of time.


General illumination for open offi ce areas is controlled by the =S= system on

a zone basis. Lighting automatically comes on in the morning to greet arriving

employees. At the end of the workday, lighting is automatically switched off. To

prevent tampering, the switch is disabled during normal work hours. Later in the

evening, the cleaning crew and late working persons uses the same switch to

turn on lighting for a programmed period of time. The potentially harmful effects

of inrush generated by switching large fl uorescent loads is nullifi ed by the =S=

control system’s zero-cross switching technology.

Scheduled Zone Control with light level sensing

General illumination for open offi ce areas is controlled by the =S= system on

a zone basis. In the morning light switches are automatically enabled to allow

manual switching. At the end of the workday, lighting is automatically switched

off. Under day time a light-level sensor dims or turns out the lights if incoming

daylight is on a suffi cient level. Later in the evening, the cleaning crew and late

working persons uses the same switch to turn on lighting for a programmed

period of time. The potentially harmful effects of inrush generated by switching

large fl uorescent loads is nullifi ed by the =S= control system’s zero-cross

switching technology.

Automatic Contrast Control

Lobby lighting is often a compromise between aesthetics and saving energy. In

this case, the light-level sensor is set to increase the level of feature lighting in

the lobby during the day to maintain a pleasant balance with the level of sunlight.

This photocell operation is automatically disabled during weekends.

31

Programmed Visual Interest

A time schedule automatically sets the lobby lighting to appropriate levels to

enhance the exterior visual appeal of the building during early evening hours.

Later in the evening, the schedule turns off all lighting in the lobby except for

security lighting.

Exterior and Site

Dusk to Time Operation

The exterior and site lighting is automatically turned on in the evening by the

schedule. Light level sensors controls the logic and allows the system to react

on the actual outdoor light level for the local area. All exterior lighting is utilized

during early evening hours. Later, most of the exterior lighting is turned off by

the schedule to conserve energy and reduce sky glow.

Adjusts to Environmental Conditions

Stormy or overcast conditions may call for exterior lighting and signage to

turn on earlier than scheduled. A building-mounted weather station monitors

these conditions and passes light-level, temperature, windspeed and humidity

information to the =S= control system. This information is used to control and

override weather dependent functions like sunshades and external pavement

heating systems. Because the site lighting is spread out over a large area, multi-

pole lighting circuits are required to effi ciently distribute power to the lighting

poles. The =S= relay panel provides integral control of multi-pole circuits without

external contactors.

About Scheduling

The most basic controlling strategies involve time-based controls, best suited

for spaces where lighting needs are predictable and predetermined. Time-based

controls can be used in both indoor and outdoor situations. Common outdoor

applications include automatically switching parking lot or security lighting based

on the sunset and sunrise times. Typical indoor situations include switching

lighting in production, manufacturing, and retail facilities that operate on fi xed,

predefi ned operating schedules. Time-based control systems for indoor lighting

typically include a manual override option for situations when lighting is needed

beyond the scheduled period.

32


Control of general lighting in spaces which has a predetermined usage.

For security reasons some areas may need to have a decreased light

level. Time-based control can be used both inside and outside.

Control needs

ON/OFF and/or dimming control with manual or automatic override

possibilities

33

The TAC Xenta 511 is a web based presentation system for LONWORKS networks.

Using a standard web browser, the operator can easily view and control the

devices in the LON network via Internet or a local intranet. One TAC Xenta 511

can present a small LON network or be one of several local presentation devices

in a larger network. Time schedules and trend logs are easily accessed. For

setting see data sheet

Adjusting artifi cial light levels in response to changing levels of natural light is

an important strategy used in modern lighting control systems. The =S= system

supports both exterior and interior photocell inputs for implementation of both

open- and closed-loop lighting control strategies. Monitoring of exterior ambient

light levels provides appropriate input for effective dusk-to-dawn or dusk-to-time

control. =S= controls also incorporate the sophisticated logic required for interior

daylight harvesting control using fl uorescent fi xtures equipped with electronic

dimming ballasts.

Open Offi ce Area

Manual Zone Control with daylight harvesting

Manually switching on lighting in the morning maximizes energy savings. The

natural light made available through glazing can be harvested by a local photocell

that dims the fl uorescent lights in proportion to the ambient light present.

The day lighting logistics are handled automatically by logic built into the =S=

combined light-level and occupancy sensor.

The system automatically maintains the light level by varying the control signal to

the light fi xtures in response to signals from the photocell. To prevent tampering,

the switch is disabled during normal work hours. Later in the evening, the

cleaning crew uses the same switch to turn on lighting for a programmed period

of time.


General illumination for open offi ce areas is controlled by the =S= system on a

zone basis. Lighting automatically comes on in the morning to greet arriving

employees. The natural light made available through glazing can be harvested by

a local photocell that dims the fl uorescent lights in proportion to the ambient light

present. The daylighting logistics are handled automatically by logic built into the

=S= combined light-level and occupancy sensor.

4.4 Constant LightControl

34

About Constant Light Control

Lighting level-based strategies take advantage of any available daylight and

supply only the necessary amount of electric light to provide target lighting

levels. In addition to saving energy, lighting level controls can minimize over

lighting and glare and help reduce electricity demand charges. The two main

strategies for controlling perimeter fi xtures in day lighted areas are daylight

switching or daylight dimming.

Daylight switching involves switching fi xtures off when the target lighting levels

can be achieved by utilizing daylight. To avoid frequent cycling of the lamps and

to minimize distraction to occupants, a time delay, provided by a deadband, is

necessary.

Several levels of switching are commonly used to provide for fl exibility and a

smooth transition between natural and electric lighting.

Daylight dimming involves continuously varying the electric lighting level to

maintain a constant target level of illumination. Dimming systems save energy by

dimming fl uorescent lights down to as low as 10 to 20 percent of full output, with

the added benefi t of maintaining consistent lighting levels. Because HID sources

cannot be frequently switched on and off, they are instead dimmed for time,

occupancy, and lighting level-based control strategies.

35


Control of general lighting with an automatic control that replaces or

accompanies occupant control, in order to conserve energy, by switching off

or dimming the electric lights when full output is not needed.

Control needs

ON/OFF and/or dimming control with manual override possibilities

36

4.5 Dimming Control

Introduction

Dimming controls make high performance fl uorescent dimming practical.

Many commercial and institutional spaces have different activities that would

benefi t from dimming control, particularly the ability to create scenes or presets

with dimming of individual groups of lamps.

Dimming controls are available for most types of lighting. They ca be integrated

into automatic liqhting control systerns and can be used manually as well. Some

dimming controls require use of magnetic or electronic dimming ballast, while

others employ an electronics dimmer package installed in the panelboard or

elswhere within tbe system.

Depending on the type of load it can be controlled either directly by a dimmer

using phase cutting (incandescent, halogen and low voltage halogen lamps) or

with a 1-10V or DALI control signal, controlling the ballast (fl ourescent tubes).

The 1-10V signal has to be wired separetly for each group it controls, while DALI,

beeing a bus structure, allows individual control of up to 64 lamps.

Benefi ts of DALI control are :

• increased fl exibility in building operations

• reduced installation costs

• reduced initial costs compared to conventional 1-10v dimming control systems

• lower energy costs than with non-dimming lighting control

• easily adaptable to changing needs

• scalable for future expansion

An DALI system consists of a power supply, a controller, DALI ballasts, and a

DALI bus.

Furthermore, a practical system will also include sensing devices such as push

buttons for choosing dimming, scene settings, daylight sensors that provide local

data to the controller, which will, in turn process the inputs and send appropriate

DALI commands over the DALI bus. Programming typically resides in the

controller. The primary application is single room, stand-alone control dimmer

and scene control.

With the DALI Controller, users can access up to sixteen scenes for a room. These

scenes are stored in the DALI ballasts for immediate recall, and users simply

refer to a scene by its functional name (i.e., “presentation”).

37

About DALI light control

Integration of DALI with a building management system is both simple and

fl exible. DALI can be deployed as a subsystem to a BMS. While the DALI control

unit or gateway responds to commands from the BMS control, such as central

overrides for timed on/off switching or dimming, DALI ballasts feed lighting

system information back to the BMS, allowing automatic identifi cation of failed

lamps and ballasts as well as central monitoring of ballast power and dimming

levels.


A meeting room is equipped with partition walls to allow fl exible use of the

space. When partition walls are open the space is used for larger meeting

or as presentation room with a stage in one end. One side of the space has

large windows. Constant light levels are desired during for maximum energy

conservation. For cleaning, suffi cient light levels and energy conservation are the

goals.

Control needs

ON/OFF and/or dimming control with scene setting and daylight harvesting.

38

The versatile meeting room can be divided into three spaces with movable walls,

each space having its own set of pushbuttons to allow individual control. When

partition walls are open and the space is used for larger meetings all pushbuttons

work in parallel. One side of the space has large windows allowing daylight

harvesting.

In this simple scenario, fi ve (5) lighting schemes were defi ned and programmed

at installation (although sixteen schemes are possible):

39

4.6 Shutter Control

Scheme 1: Constant light control (use of daylight) for meetings. Groups 1-9 are

programmed for varying light levels.

Scheme 2: Evening activities. Groups 1-9 are programmed at 100% light levels.

Scheme 3: Stage lighting for presentations Group 10 only is programmed.

Scheme 4: Lighting for cleaning Groups 1-9 are programmed at 50% light levels.

Scheme 5: Security lighting. One light from each Group 1-9 is programmed at

10%.

To achieve this, four groups were defi ned and programmed as follows:

- Groups 1-3, groups 4-6 and groups 7-9 are arranged in parallel to the windows

in order to create ideal conditions for daylight control. - Group 10 is wired

separately to highlight the stage on special occasions.

If these groupings needed to be changed, the fi xtures would simple be

reassigned to new groups via remote control or PC - no ladders, no pulling wires,

complete fl exibility!

Shutters and blinds not only protect us from the sun, creating pleasant lighting

conditions, they can also help make a signifi cant contribution to saving energy

costs for heating, cooling and artifi cial lighting.

=S= control systems includes shutter actuators in different functional versions

for the control of shutters, interior blinds, awnings or motorized curtains

Types and operation

Wind Control - Retracts external blinds if the wind speed exceeds a pre-set level.

Timer Control - a daily or weekly timer to operate the blinds at preset times. It

is usually used to extend the blinds in the morning and retract them at night.

Where blinds or shutters are used for insulation it can be used to lower them at

night for heat retention.

Light level control - for non-retractable blinds has three lux level control and

allows the slats to adjust to maintain light levels within a selected band width.

Master or Building Control - allows override of the system from one central point

with the option of an interface with the fi re alarm system to retract the blinds.

Individual control - allows override of the automatic system by a switch local to

each blind.

Infra-red control - operation by means of an infra-red transmitter that activates

the sensor that is normally mounted on the wall beside the blind.

Radio remote control - control by a hand held transmitter is usually used for

shutters or garage doors. It is suited when direct line of sight to the sensor is not

possible.

40


Control of shutters and blinds with an automatic control that replaces or

accompanies occupant control, in order to ensure that external blinds are

retracted in windy conditions or extended at sunny conditions following the data

from the BA system.

Control needs

Automatic UP / Down and slats control with manual override possibilities

41

5 Application practice

Light Control with LON

42

In a room the following SVEA LONWORKS modules were implemented for

lighting control:

LON I/O-Module REG-M DIM as Control Output 1 V...10 V

The lighting in this room is in the form of fl uorescent lamps with dimmable

electronic ballasts. The electronic ballasts are equipped with an interface

1 V...10 V. They are controlled by a LON I/O module from the company

SVEA. This LON I/O module possesses an analog output (1 V...10 V) for the

dimming function and a relay output (NO-contact, 10 A) for switching the

supply voltage for the electronic ballasts.

LON Multisensor ILA-22

A SVEA LON multi-sensor, ILA-22, is a combination of presence detector,

brightness sensor and infrared receiver, mounted on the ceiling. It recognizes

whether people are in the room using a presence detector and sends this

information to the LON network. The brightness sensor supplies the actual

value of the brightness in the room, e.g. for constant light control. The

infrared receiver processes the signals from an infrared remote control and

sends information to dim the lights and for other lighting scene settings to

the LON network.

LON Bus Coupling Unit UP with Switch Application Module

The information sent by the infrared remote control for the multi-sensor can

also be sent by one or more fi xed wall switches.

43

Software Description

SVEA LON I/O Module REG-M DIM as Control Output 1 V … 10 V

The application serves the dimming and switching of fl uorescent lamps via

electronic ballasts with an interface 1 V...10 V, or of NV halogen lamps via

transformers with an interface 1 V...10 V.

With the aid of a brightness sensor, constant light control can be achieved.

Furthermore, it is possible to save lighting scene settings and to retrieve

them when required. Certain lighting moods can hereby be quickly re-

established through one click on a button. The information from the

presence detector can be used to switch off the light completely or to dim it

to a particular level.

In the LON I/O module, the following LONMARK objects are available: Lamp

Actuator (3040), Constant Light Controller (3050), Scene Controller (3251)

and Occupancy Controller (3071).

SVEA LON Multisensor ILA-22

The application enables movement and brightness-dependent control via

the LONWORKS network. By means of an infrared remote control, lighting

scenes can be activated and switching or dimming orders for blinds and

luminaires can be sent. The following LONMARK profi les are implemented in

the application: “Occupancy Sensor (1060),” “Occupancy Controller (3071),”

“Light Sensor (1010),” “Scene Panel (3250)” for the remote control, and

“Switch (3200)” for the switching, dimming and blind sensor.

The presence detector, with an integrated brightness sensor, registers

movement in its surveillance area and, upon any changes, sends the

corresponding status (“OCCUPIED” or “NOT OCCUPIED”) to the bus. The

current status can also be cyclically sent at adjustable time intervals. At the

same time, the brightness value received via the integrated light sensor is

made available.

An infrared remote control enables the retrieval of fi ve different lighting

scenes, as well as the switching and dimming of luminaires.

44

LON Bus Coupling Unit with Switch Application Module

For the SVEA LON Bus Coupling Unit UP there is a very fl exible software

application that can be confi gured for almost every planned application. It

is based on the LonMark profi les “Switch (3200)”, “Scene Panel (3250)” and

“Occupancy Sensor (1600)”.

The applications for the switching or dimming of luminaires and for the

sending of scene setting values are described in the following examples.

Application “Manually Dimming Lights”

1. The movement sensor in the LONWORKS multisensor sends the current

occupied status to the movement controller via the output variable,

nvoOSOccupancy.

2. If the status changes to “OCCUPIED” mode, a switch-on order is sent

via the output variable, nvoOCLampValue. The type of this variable is

SNVT_switch. The value for the switch-on order can be set in a confi guration

variable. The lamp switches on and is dimmed to this set value. If movement

is no longer reported, an adjustable time delay starts. If no movement is

detected after this time delay, nvoOCLampValue sends an “OFF” order (state

= 0, value = 0).

45

3. Through operating a switch on the bus connector, the dimming value, and

thus the brightness of the lamps, can be altered. As long as the switch is

pressed, messages are distributed via nvoSWswitch in which the value-part is

gradually enlarged or reduced, according to the dimming direction. The size

of the dimming stages can be set in a confi guration variable.

4. The dimming actuator reports its current status to the LON network via

the feedback variable, nvoLAlampValueFb. This value must be bound to the

input variable nviSWswitchFb of the bus connection because it is only from

the current dimming value that brightening or dimming occurs.

Application “Daylight Dependent Control” with Manual Dimming

46

1. The movement sensor in the LONWORKS multisensor transmits the

current occupied status to the movement controller via the output variable,

nvoOSoccupancy.

2. If the status changes into the “OCCUPIED” mode, a switch-on order,

SET_ON, for the constant lighting control is sent via the output variable,

nvoOCsetting. The control is now activated. If movement is no longer

reported, an adjustable time delay starts.If no movement is detected

after this time delay, nvoOCsetting sends an OFF order, SET_OFF, to the

controller.

3. During active control, the actual value of the brightness, which should be

present at nviCLluxLevel, is compared with the programmed setpoint value

(nviCLLuxSetpoint or SCPTluxSetpoint). If the two values differ from each

other, an output value (value-part of the SNVT_switch-Variable) is calculated

in order to dim the connected luminaire. Via a confi guration variable, the

value to be sent fi rst can be defi ned after switching on the control. If the

control is switched off, a switch-off message is also sent to the dimmer

actuator. It is possible to switch off the light automatically to save energy

as long as the actual value lies above a defi nable value due to outside light.

4. The output value calculated by the control is sent via nvoCLlampValue

to the dimming actuator which, in turn, correspondingly sets the interface

1 V...10 V, whereby the new value can be gradually dimmed in adjustable

steps.

47

5. If the brightness is to be altered manually, this can either be achieved via

an infrared remote control in connection with the LON multisensor or via a

button on the LON bus connection. Through operating the buttons, SET_UP

or SET_DOWN commands are sent to the input variable, nviCLsetting. This

leads internally to a change in the brightness setpoint, so that the connected

lamp is dimmed accordingly until the actual value is again in harmony with

the setpoint. The temporary setpoint programmed in this way is valid until

the control is switched off.

Application “Scene Control with Manual Dimming”

48

1. The movement sensor in the LON multisensor transmits the current

occupied status to the movement controller via nvoOSoccupancy.

2. If the status changes into the “OCCUPIED” mode, a switch-on

command, SET_ON, for the scene controller is sent via the output variable,

nvoOCsetting. If movement is no longer reported, an adjustable time delay

starts. If no movement is detected after this time delay, nvoOCsetting sends

an OFF command, SET_OFF, for the scene controller.

3. If a scene value (SC_RECALL) is received at nviSCscene when the scene

controller is active, the corresonding saved output value is sent to the

dimming actuator. After switching on, the last set scene value will be sent.

If the controller is switched off, a switch-off message will also be sent to the

dimming actuator. If a SC_LEARN command is received at nviSCscene, which

49

can be evoked through lengthened operation of the desired button on the

infrared remote control or on the bus connection, the status received at that

time at nviSCswitch will be saved as a scene under the sent scene number

(see also point 6).

4. The scene-dependent, saved output value is sent via nvoSCswitch to the

dimming actuator which then correspondingly sets the interface 1 V...10 V,

whereby the new value can be gradually dimmed in adjustable stages.

5. If the set scene value is to be altered manually, this can either be

carried out via the infrared remote control in connection with the LON multi-

sensor or via a button on the LON bus connection. Through operation of the

buttons, SET_UP or SET_DOWN, commands are sent to the input variable,

nviSCsetting. This leads internally to an alteration in the saved scene value

so that the connected lamp is correspondingly dimmed.

6. If messages are received at nviSCswitch, these are passed on directly

via nvoSCswitch to the dimming actuator. Adjacent values can be saved as

new scene values by means of a LEARN command to nviSCscene.

7. The dimming actuator sends its set value at that time to the LON

network via the feedback variable, nvoLAlampValueFb, for the purpose of

synchronising the buttons.

Dimming via point 3 or point 6 can be used alternatively, whereby new scene

values can only be saved with the procedure described in point 6.

Note: the applications described are carried out using software applications

from Schneider. Software applications from other manufacturers can deviate

from these in their functionality.

Documents

Lighting Control Systems