Lighting regulation and control systems (Part 1)

Under the premise of smart light use, these systems offer a lighting that adapts to the needs of each installation and situation, creating suitable ambiences for all times and providing both a high degree of comfort as well as considerable cost savings.

The energy saving made possible by these lighting regulation and control systems, in addition to the economic saving, has an extremely positive effect on the environment, given that less power consumption means both a reduction of CO2 emissions as well as a sustainable use of the natural resources and power sources, thus contributing to environment conservation.

A. Regulation methods

Leading & trailing edge dimming:
This type of regulation is accomplished without any need for an additional control wire. It involves connecting a regulator in series between one of the mains wire and the equipment.

The regulator cuts part of the mains voltage sinusoidal waveform to a greater or lesser extent in order to regulate luminous flux from 1% to 100%.

Depending on how the mains voltage cut is made, it is possible to distinguish between two types of regulation:

Leading-edge dimming: Regulation by means of cut-off in the wave on its rising side, from the beginning (phase cut-off at ignition). This is habitually used in halogen lamps supplied through electromagnetic transformers.

Trailing-edge dimming: Regulation by means of cut-off in the wave on its descending side, from the end cutting back¬wards (phase cut-off at switch off). This is the most suitable for halogen lamps supplied through electronic transformers .

There are regulators and equipment that support both types of regulation, and others that support only one type.

In the marking of these systems with phase cutting regulation you can see indications of what type of cut is involved:

1-10V regulation:
The 1-10V system enables regulation of the luminous flux from around 1% to 100% by means of an analogue signal to the equipment over an additional, two-wire additional control line. These control wires have positive and negative polarities respectively and must be borne in mind when wiring up the system.

The analogue signal has a direct voltage value of 1V to 10V. Minimum light is obtained 1V or by short circuiting the equipment’s input control, while maximum light level is obtained 10V or by leaving the input control circuit open.

The line control only enables regulation of the luminous flux, the switching-on and the switching-off of the light, which can take place at any regulation point. It is done by fitting a switch on the equipment’s power line. Both lines, the control and power one, are electrically separated from each other.

The regulation curve that represents the relationship between the control line voltage and the luminous flux is defined by the international standard, IEC 60929 and reflects a practically lineal relationship in the range of 3V to 10V.

To get a response adapted to that of the human eye it is possible to use logarithmically controlled potentiometers.

Power control is generated by these in lighting equipment with 1-10V regulation. A current is supplied to the controller by means of equipment control terminals. The controller current must be from 10uA to 2mA. The maximum control line current is obtained with a voltage of 1V and the minimum with a voltage of 10V.

This regulation system is unidirectional, i.e. the information flows in one direction, from the controller to the light equipment. The latter generates no type of feedback to control. It does not allow for addressing by means of equipment software. Groups have to be created by wiring. This system can be integrated into building control systems.

The length of the control line wiring is limited by the voltage drop that occurs along it, therefore, the maximum distance is limited by the number of control gears connected to be controlled. The latter establish the current per line and the cable diameter used.

Regulation by means of Touch Control pushbutton:
Touch Control is a system that enables the simple and economic regulation of luminous flux. It uses the mains voltage as a control signal, applying it by means of a normally open, standard pushbutton on a control line, without any need for specific controllers.

The Touch Control system enables you to carry out the basic functions of a regulation system by means of power-free pushbutton. Depending on how long the button is pressed it is possible to switch the light on or off or regulate it. Switching the light on or off is done by short, sharp pressing or “click”. If the button is pressed for a longer time it is possible to regulate the luminous flux between the maximum and minimum levels alternately.

This is a unidirectional interface, i.e. information flows in one direction. The equipment does not generate any type of feedback. It does not allow for addressing by means of equipment software. Groups have to be created by wiring. This system cannot be integrated into building control systems.

The length of the wiring and the number of equipment that can be connected up are unlimited in theory, but in practice at longer distances of over 25 metres, and with a bigger number of pieces of equipment connected, asynchronism may occur during switching on and dimming at different points of light simultaneously. Owing to its characteristics, the use of this regulation method is recommended for individual offices, small meeting rooms or bedrooms, landings and small spaces in general.

DALI regulation:
As revealed by the meaning of this acronym, Digital Addresable Lighting Interface, DALI is a digital and addressable communication interface for lighting systems. This is an international standard system in accordance with IEC 62386, which ensures compatibility and interchangeability between different manufacturers’ equipment marked with the following logo:

(This solution will be developed in our next post)

B. Control system components
Apart from the light source to be controlled, lighting management systems are made up of other additional components. Among these you have control gears, switches and command wire equipments, sensors, controllers, adaptors, repeaters, converters, gateways and configuration and monitoring tools.

Control gears:
Lighting control gears, drivers for LED modules, ballasts for fluorescent and discharge lamps, transformers for halogen lamps are the components commissioned with making the light sources work properly. They must be adjustable by the control method chosen to enable their integration into a lighting management system.

Switches or control elements:
These are components by means of which the user interacts with the lighting management system, making it possible to switch the light on and off and regulate it directly by hand. This group consists of pushbuttons, knobs and control panels.

Sensors and detectors:
These are devices capable of detecting physical and chemical magnitudes and transforming them into signals that can be processed. In lighting management systems, presence detectors and photocells are particularly important as they serve to switch on and off and regulate the lighting automatically, depending on the presence of persons and the natural level of light in the space to be illuminated.

Control units and controllers:
These components serve to receive all the information from the rest of the system’s components, process it and generate the control orders to be distributed intelligently.

Repeaters:
These are components that amplify the level or power of weak signals, thus, in lighting management systems, they must be used when longer wiring distances are required, or a greater number of equipment needs to be connected than is allowed in principle.

Configuration and monitoring tools:
More advanced lighting management systems need software tools to enable their addressing, programming, parameterising and monitoring.

A solution for every application:
Lighting management systems can be more or less complex depending on the solution chosen for each one; the control method chosen, the number and type of components, the interconnection between them and their integration with buildings’ control systems.

There are a wide range of possibilities ranging from the simplest solutions consisting of individual luminaires fitted with adjustable equipment and photocells connected directly between them, which regulate the light separately from the rest of the lighting, to more advanced lighting management systems, integrated into the smart control of buildings, which can control luminaires in different rooms and on different floors with multiple uses, to the extent of being able to create different atmospheres adapted to each situation and to report information on their status at all times.

Jesus Gallego, R&D Department