How does KNX lighting control work

Quick Answer FAQs

How is KNX Lighting Control Operated?

KNX lighting control work  is a communication network that connects different devices, such as switches, sensors, lighting actuators, dimmers, etc. Whenever someone presses a KNX switch or a sensor detects movement or light level changes, the KNX lighting control will send a programmed command to the corresponding actuator, which will switch, dim, or adjust the light.

What Capabilities Does KNX Lighting Control Have?

With KNX lighting control system you may switch lights ON/OFF, dim, light up different areas (scenes), set up lighting schedules, use smart light which automatically changes with movements, let the light follow the daylight cycle and even switch all the lighting centrally.

Does KNX Controller Work With LED Lights?

Undoubtedly, you need KNX actuators or dimmers and dimming devices which are compatible with your LED lighting for KNX lighting control to run smoothly. With the help of suitable interfaces, the controller can operate the lights.

Is It Possible For KNX Lighting To Be Automatically Switched On?

Definitely. KNX lighting control can be configured so that lights go on automatically depending on the occupancy, motion, daylight, schedules, and other programmed situations.

Can KNX Lights Be Installed In Dwellings And Offices?

Of course, lighting automation with KNX can easily be integrated in private homes, apartments, villas, offices, hotels, retail spaces, meeting rooms, etc. Commercial buildings will appreciate this as well.

What Happens When KNX Lighting Control Is Used?

Purely, KNX lighting control allows lighting devices and control components to interact with each other through a single network, which is usually building automation network. It is not required to join every light to a switch through a wire in a traditional way. The main point here is that smart control devices that come with push buttons, sensors, actuators, dimmers, and controllers can work using KNX protocol.

What Would A Classic KNX Lighting Control Scenario Look Like?

Person makes the request → The KNX system sends the command for it → The actuator gets the request → Lighting is either switched ON/OFF or bright light is changed

With the help of KNX, you can also make use of different lighting scenarios without physically pressing buttons.

KNX lighting control scenario

Motion is detected → The KNX sensor sends the message → Lighting actuator gets the instruction → Lights come on

Because of being an integrated network solution, KNX is able to connect lighting to the broader building automation system. This is very convenient, for instance, to control all lights from one place, to set a certain temperature in the room when a room is not occupied, to automatically turn off appliances etc. All these are possible when you integrate lighting in KNX.

About KNX Lighting System

KNX is a technology standard applied for automatic home/apartment control. In KNX lighting control installation, various devices cooperate to realize electrically controlled functions and lighting controls.

An average KNX lighting system will consist of:

• KNX push buttons
• Presence detectors
• Movement detectors
• Light level meters
• Electro-mechanical switches with KNX
• Dimmer actuators with KNX
• LED interface devices
• KNX mains
• Touch panels or display systems
• Controllers or gateway units for building automation systems

The parts you will need will vary depending on the kind of project.

How a KNX Lighting System Works Step by Step

1. The User or Sensor Generates an Input

A lighting command can start in several ways.

We humans are usually the ones triggering a lamp switch, but that doesn’t always happen manually.

We might be the trigger, but the presence sensor can be one too in case of our entrance detected in the room.

There also can be other inputs besides that like:

• Daylight levels
• Time schedules
• The overall command from central systems like lighting control
• The interaction with touch panels
• Visualization programs
• The coordination of different building management components

In all these cases, it is the input which will prompt the KNX lighting system to perform an action.

2. The KNX Device Sends a Command

The KNX control device will send a digital message or a telegram, via the KNX communication network.

The message or telegram sent will be the representation of the various functions such as:

• Light ON
• Light OFF
• Light up the room more
• Darken the room
• Set a specific brightness
• Bring the lighting scene to life

One illustration:

Button was pressed, therefore, ON command was sent.

The corresponding KNX actuator shall be programmed to do the job.

3. The KNX Actuator Controls the Lighting

Switching or control of the power, whether turning a light on or a power strip off the KNX actuator is doing it all.

For basic lighting:

Receiving the command via the knx-bus Switching actuator Light turned on

On the other hand, for lighting that can be dimmed:

knx-bus Dimming actuator/interface Brightness changed

KNX Lighting Switching

The basic light control for KNX is ON/OFF.

A key point when discussing KNX systems is that wall switches can be programmed in such a way that a button press leads to the transmission of a command to an actuator.

One simple instance of this process could be:

Press once → Living-room lights ON

Press again → Living-room lights OFF

Of course, different lighting circuits can each be controlled individually.

It might be possible for one KNX switch to handle the following lights:

• Ceiling lights
• Wall lights
• Decorative lighting
• Dining lights

Such functionality offers more possibilities as, e.g., a standard switching unit would do.

KNX Lighting Dimming

In general, besides switching the light ON and OFF, one also can choose among different brightness levels with KNX.

This dimming facility is only possible if dimming-compatible equipment is installed.

The following examples can be imagined:

• Very bright (100%) for cleaning
• Rather bright (70%) for everyday purposes
• Medium bright (40%) in the evening
• Pretty dim (20%) for a relaxation atmosphere

Thus, KNX sends over a specific level of light to the fitting dimming device.

Knx lighting dimming in this way is very effective for residential, hotel, restaurant, office or conference space applications.

KNX Lighting Scenes

Arguably, one of the main advantages of KNX lighting, is the use of scenes i.e., automation of lighting conditions.

A scene basically is a collection of lighting functions that are triggered at the same time via a one touch command.

Basically a living room could have:

Welcome Scene

• Switch main lights ON
• Switch decorative lights ON
• Other lights will be operating in accordance with their individual programming

Movie Scene

• Dim the main lights a lot
• Dramatically reduce the output of decorative lighting
• Turn the other lights OFF

Night Scene

• Some lights to be turned OFF
• Pathway lights to operate with minimum light

The activation of scene via touch panel, KNX push button, visualization system and other programmable devices by the user is possible.

Motion and Presence Sensors

You can also set up automatic lighting control with a KNX system by using occupancy-related sensors.

For example, if someone has been in a corridor for a while:

Person detected → KNX Sensor → Lights go on

If there is no movement anymore after a certain time that has to be programmed:

No occupancy → KNX system → OFF command → Lights go out

KNX Lighting and Daylight Control

KNX system, besides lighting control, offers integrating daylight with artificial light in one control system.

A light sensor can detect the available level of daylight, based on the system type installed.

For instance:

High daylight decrease artificial lighting
Low daylight increase artificial lighting

Using such type of automation, lighting level could be kept at desirable level while at the same time minimizing wasteful use of artificial lighting.

Furthermore, daylight control can be connected with motor-driven blinds or shades. In one example scenario: Bright sun blinds change position light level gets adjusted. The behavior is completely dependent on the combination of different sensors, actuators, a programming, and system layout.

Centralized KNX Lighting Control

KNX is also able to offer the facility of a central place for operating the lights.

For example, the householder could install a central ‘All Lights OFF’ function just outside the main entrance to the residence.

On top of that, a company manager might prefer having centralized lighting control for selected sections of a building.

Here is an example list of centralized functions:

• All lights ON
• All lights OFF
• Floor-level control
• Area-level control
• Lighting commands related to emergency situations
• Scheduled lighting

Managing big projects using such a system will surely be more convenient.

KNX Lighting Control Example for a Smart Home

We present a modern KNX automated villa as an example.

Living room features:

• Ceiling LEDs
• Decorative lights
• Automatic motorized curtains
• Presence detection sensor
• KNX wall switch

KNX lighting controls in the villa are set up to turn the ceiling lights on when the ‘Evening’ scene button is pushed:

• Lights the ceiling lights.
• Selects brightness level to light the ceiling lights
• The decorative lights get light on.
• Cutains opening is done through the automation system.

KNX Lighting Control Scenario for an Office

KNX can be used to synchronize several functions in an office meeting room:

• Room occupancy sensor
• Lights
• Dimmers
• Window shades
• Integration with Heating & Ventilation (HVAC)

When the room occupants turn on, for example, the presence sensor may trigger the lighting to a programmed state.

For the presentation, a scene can be activated that dims certain lights and changes the position of the blinds.

Once nobody is in the room and the timer is off then lighting can be fully switched off or only the night light level is maintained according to the automation logic.

Advantages of KNX Lighting Systems KNX lighting system automation can bring several useful features:

Different Modes of Operation

Room-specific needs and conditions can dictate which lighting functions are set up and how.

Automation

Use of sensors and timers can minimize reliance on direct manual switching of lights.

Scene Setting

With just a single command, it is possible to change lighting to a desired setting.

Single Point Control

Designated lighting circuits can be operated from one location using a central control unit.

System Integration

It will be possible to coordinate with blinds, HVAC, sensors, energy-management systems, and various other building technologies through lighting.

Growth Flexibility

KNX systems can be tailored to meet the needs of individual rooms or whole buildings.

Compatibility of KNX with LED

KNx  can be used to control LED if the KNX system, the drivers the actuators of the LED are KNX.

For instance, ON/OFF control may be implemented through suitable KNX switching devices and compatible dimmers may be used to vary the level of brightness on a dimmer.

A set of the LED driver, dimmer type, actuator and KNX interface are chosen to work well together.

KNX vs  Control without KNX

Without any advanced system, will be activated just by flipping the light switch that electrically connects the circuit of the light.

KNX adds the concept of networked devices and programmable logic to the lighting control system.

KNX Lighting vs Traditional Lighting Control

Traditional lighting typically relies on direct electrical switching through conventional switches.

KNX introduces communication and programmable logic into the lighting system.

Final Answer

A KNX lighting control installation is done by connecting switches, sensors, actuators, dimmers, and lighting equipment via the KNX automation network. A switch or sensor will trigger a programmed command, after which the appropriate KNX actuator will act accordingly and carry out the lighting action that is requested.
This kind of system can also provide ON/OFF switching, dimming, scenes, automatization depending on the presence of the user, daylight control, programmable timers, and centralized lighting management.

On one hand, the device offers switching between ON/OFF, dimming, creating different scenes, automatic operation based on occupancy and daylight sensors, scheduling, and light control that is managed through one unit. On the other hand, KNX is not limited to lighting as it can be used to communicate with all building systems. Lighting can then be integrated with other systems such as blind operation, heating, ventilation and air-conditioning, energy management, and so on to form a smart building environment that is controlled by a set of programmed conditions.