DALI electronic ballast dimming

1 Common dimming control method for electronic ballast


With the development of computer technology, computer technology and computer network technology have continuously penetrated into various electronic products, and their performance indicators have been greatly improved. Since electronic ballasts are energy-saving and easy to implement the advantages of dimming control, they are widely used throughout the world. The current common control methods for lighting computer dimming control are: DALI, DMX512, TCP/IP, various fieldbuses (such as CAN, C-BUS, CC-LINK, European installation bus EIB, etc.). The computer dimming control system composed of TCP/IP control protocol has the advantages of mature technology, convenient use, wide control range and easy promotion. It has great advantages in large-scale dimming control system, but the cost is relatively high. complex. The DMX512 control protocol is widely used in the film and television industry, and the control capability and control range of the TCP/IP control protocol are weaker. The DALI electronic ballast dimming control protocol is a control protocol specially proposed for the dimming control of fluorescent electronic ballasts in Appendix E of IEC929. It is simple, convenient and easy to implement.

This paper mainly introduces the characteristics and use of DALI electronic ballast dimming control software developed by DALI control protocol and American IR company and Microchip company.

2 Digital Addressable Lighting Dimming Interface Standard (DALI)

Due to its openness, DALI adopts digital control technology and adopts DALI to form an addressable digital dimming control system, which has the characteristics of low cost, easy installation, flexible system reconstruction, and cascading (composed of master/slave control system). It is ideal for lighting control systems in buildings such as office buildings, conference halls, concert halls, warehouses, universities and residential areas. It can be used together with today's widely used building management systems such as EIB, LON, LUXMATE and BATIBUS. Provides a more complex and integrated lighting control system that is now part of the international standard IEC 929 for lighting control (electronic ballasts) and the European standard for lighting control (electronic ballasts) EN 60929 (Appendix E) It plays the role of energy saving (up to 30% energy saving) and environmental protection, and has been supported by the world's major electronic ballast manufacturers, and has been widely used.

2.1 Reasons for using DALI

DALI is an addressable, new industry standard protocol for fluorescent lamp electronic ballast control that can revolutionize the lighting industry. Has the following features:


(1) Energy saving by lighting can save up to 30%;
(2) It is convenient to realize lighting control;
(3) The maintenance cost of the system can be reduced by the working state of the lamp and the central monitoring of the electronic ballast;
(4) The system is simple to install, the use of components is less than the analog control system, and the system cost is low;
(5) Due to the digital control, the DALI dimming control system can control each electronic ballast, and the analog control system can only control each group of electronic ballasts, so the DALI dimming control system is flexible. Very high;
(6) “Plug and play”, the interchangeability and flexibility of each manufacturer's products are good;
(7) DALI is an open control system, and electronic ballasts produced by different manufacturers can receive DALI.

2.2 DALI development background

Due to the demand for energy saving In the 1990s, the development and research of digital fluorescent lighting control systems began in Europe. Some major lighting manufacturers have proposed the use of standard communication protocols to accelerate the promotion and use of group-controlled lighting energy-saving products.

Architects are also very concerned about the compatibility of lighting group control communication protocols and equipment. After DALI, products from different lighting equipment manufacturers (such as control systems, electronic ballasts, sensors, etc.) can be seamlessly interconnected. The system connection is reliable and convenient, thereby reducing the development, installation and maintenance costs and risks of the system, and increasing the scope of application of the product.

Major European electronic ballast manufacturers (such as Halvar, Hüco, Philips, Osram, Tridonic, Trilux and Vosslohschwabe) have joined the DALI standard. The Electronic Control Working Group (ECG) and (IEC929/EN60929) were established to begin drafting lighting standards and form draft European standards. The resulting DALI draft later became part of Appendix E of the European Electronic Ballast Standard EN60929.

Because DALI is an open system structure standard, it can realize the electronic ballast, dimming control equipment and sensors produced by different manufacturers to form a lighting control system. Each DALI control system can be connected by twisted pair. 64 electronic ballasts, and this DALI control system can be connected with another DALI control system to form a control center with a larger control range, and the control status can ensure the feedback of the working status of each lamp and electronic ballast. Go back to the DALI control system.

2.3 About the DALI standard

Each DALI control system has a control range of up to 300 meters (maximum 250mA drive current, 2V line voltage drop), and each DALI control interface can be used in a medium-sized building. Now DALI has become a large building management A subsystem in the system that enables two-way communication through a gateway or transmitter.

DALI can simplify the wiring of the system. Each lighting device, control circuit, dimmer or electronic ballast has only one power input and digital input. Since each lighting device is connected by bus, it can be used for each group of lighting devices. It is defined and adjusted without changing the routing, which is difficult to achieve in analog dimming systems. Each DALI can be composed of 16 groups of subsystems and can be cascaded. Any electronic ballast can be assigned to any group at any time, and the control is flexible and convenient.

2.4 DALI is a software control method

The key to the DALI standard is the definition of the software core commands. The DALI data information should contain error detection, address and command information. The address information determines that the transmitted information is to the DALI module. All DALI modules use the "broadcast" addressing command mode. Addressable 64 terminals or 16 group addresses.

In DALI, the dimming signal uses 8-bit binary, "0" means off, the logarithmic dimming curve is used, the range is 0.1%-100%, and the binary dimming signal "1" corresponds to 0.1% of the brightness, all The DALI dimming electronic ballast should meet this logarithmic dimming curve so that the human eye feels dimmed to a linear variation. Some typical DALI dimming commands are shown in Table 1. DALI has been widely used in Europe (such as OSRAM and PHILIPS have many related products), is a two-wire system that uses digital communication protocol to transmit command information, and digital control information flow format for bidirectional transmission. There are provisions in DALI.
Table 1 shows some typical dimming commands for DALI.




2.5 DALI is a versatile control system

The flexibility of DALI control, the ease of installation, the cost is related to whether it can be widely used. The simplest lighting system should contain electronic ballasts and controllers. If the sensor is used in DALI system, constant brightness control, and delivery With the light change control and infrared remote control function, the DALI control function will be stronger. Information about the operational status of the lamp and electronic ballast can be communicated between the electronic ballast and the controller, which can be used for display reporting of the lamp and electronic ballast.

DALI can be used to form a master/slave cascade control system. The DALI control unit or gateway can be used as a “master” unit for local communication, as well as to transmit and respond to feedback from any electronic ballast. The lighting of the floor or warehouse is pre-set to achieve energy savings. Each DALI terminal controller queries the dimming status information from the electronic ballast and compares the obtained dimming status feedback information with the parameters set by the local DALI terminal controller to implement the lighting control function.

DALI can also automatically realize special lighting adjustment effects such as conference rooms, audio and video applications. Users of DALI system can pre-select their own audio and video lighting effects according to their own requirements, which is automatically adjusted by DALI. Once the event is over, DALI will Turn off the illumination or dimming.

2.6 Application of DALI electronic ballast dimming system

The numerical control dimming system has many advantages over the traditional analog dimming system. The analog electronic ballast dimming system of 1V~10V has been widely used, but the analog control is not easy to change due to the fixed connection, and the use is not flexible. Additional components such as relays are required, and the control signal also produces a voltage drop across the control signal line, which in turn causes the illumination setpoint of each electronic ballast to change. However, this is not the case with the DALI system. The lead of each electronic ballast is simplified due to the digital bus and power supply circuit of the twisted pair. And there are now DALI integrated circuit series available, and the number of components used in the circuit is also small.

DALI can provide logarithmic 256-level dimming characteristics as shown in Figure 1. Even in brighter lighting environments, the dimming level varies greatly, and vice versa. This nonlinear logarithmic nonlinear dimming The visual characteristics relative to the human eye are linearly changing. The dimming effect is very suitable for the visual characteristics of the human eye.


Figure 1 DALI's 256-level logarithmic dimming curve

3 DALI dimmable lighting control software

3.1 DALI dimmable lighting control software features

(1) address, group address and broadcast addressing of the electronic ballast can be realized;
(2) relevant indicators of the working state of the electronic ballast;
(3) related indicators of the interface circuit;
(4) setting of the working state of the electronic ballast, etc.;
(5) Historical working status information of the electronic ballast;
(6) Advanced display interface for electronic ballast work;
(7) DALI basic interface commands, etc.

3.2 Use of the software

(1) DALI's main control interface

DALI electronic ballast dimming control software can communicate through a bridge circuit board and RS232-DALI interface circuit. The following describes how to use the DALI command software and information about the DALI interface circuit. Figure 2 shows the main control interface of DALI. The main functions are adjustment lamp power, dimming adjustment, on/off control, access control and related status information display.


Figure 2 DALI's main control interface

(2) Lamp power adjustment

The output power of the electronic ballast of a specific address number can be adjusted by using the % output power adjustment button on the main interface. If the selected lamp power adjustment object is a group of lamps, the output power of the entire group lamp is adjusted. Conversely, if the broadcast addressing mode is selected, the output power of all lamps can be adjusted simultaneously. The adjustment range of lamp power is 1% to 100%, and the variation law of lamp power is logarithmic (defined by DALI) to adapt to the changing law of human eye vision.

(3) Lightening time adjustment

The dimming time is the time required to change from a certain value of the lamp power to another new value of the lamp power. The dimming time slide control bar (see Figure 2 on the main interface) can be used to select 16 different dimming times. Value (as shown in Table 2).
Table 2 16 different light time values



(4) Power on/off

There are two power switches on the main control interface, they are "ON" and "OFF". When the "ON" button is pressed, the software issues the DALI control command 1 to the DALI electronic ballast. When the "OFF" button is pressed, the software issues the DALI control command 0 to the DALI electronic ballast.

(5) Electronic ballast address, group address and broadcast address selection

Port selection, polling of indicator and lamp illumination levels, event timer, update rate selection, etc. Figure 3 shows the program setup work interface.


Figure 3 program settings work interface

(6) I / O port selection

The program can be automatically diagnosed to detect serial I/O port 1, and there are four I/O ports to choose from. Therefore, if the RS232-DALI interface is not connected to port 1, it will be changed at startup. If the illuminating indicator of the main interface emits blue light instead of green light, it means that the interface circuit connected to the corresponding port works normally.

(7) Event timer

The required tasks can be accomplished through the stack registers and the DALI control command program. When a command is executed (such as changing the lamp power, changing the dimming time, etc.), the corresponding data is first pushed onto the stack and then the corresponding operation is performed. When a timer signal occurs, all signals in the stack are valid and executed. The event timer corresponding to the fault diagnosis is 500ms. Press the "update" button when changing the "Event Timer" setting.

(8) indicator / lighting driver query and update rate

"Indicator Query" is enabled/disabled to control the light and dark status of the indicator. When the main interface utilizes the illumination of the main interface to be invalid, there is no meaning. The "update rate" setting can be used to update the degree of illumination of the indicator, and the fault diagnosis update rate is 20, which means that the update rate is 20 times that of the event timer. The "Update Rate" setting can be changed by pressing the "Update" button.

The illuminance level query is enabled/disabled by the “Lighting Level” “Tools” menu, which is available in the “Lighting Level” window.

(9) Setting of electronic ballast

In DALI, each electronic ballast can be set up to complete the control of each electronic ballast function, which can be completed in the “Ballast setting” interface as shown in Figure 4. setting.


Figure 4 Electronic ballast settings

(10) Download settings

When the program is loaded for the first time, there will be no data display in the "Ballast setting" window. To complete the setting of an actual electronic ballast, set the adapted address on the main interface and press " The "Down/Load" button in the "Ballast setting" window.

(11) Change settings and upload (uploading)

Sometimes the corresponding settings can be changed in the "Ballast setting" window. The contents of the shaded window cannot be changed. To make settings or multiple settings, fill in the values ​​in the box and press the "upload" button. The relevant data will be loaded into each electronic ballast, and the corresponding address is shown in Figure 4 of the DALI command interface.

(12) Related tools

The DALI interface circuit and the DALI command software have a range of tools available to monitor and control some of the functions of their electronic ballast, such as stack information, group information, background information, and lighting levels.

(13) Information stack (information stack)

The corresponding event can be reported by the information stack through the DALI command software, and Figure 5 shows the stack interface with relevant information.


Figure 5 information stack interface

(14) Group addressing of electronic ballasts

With DALI's ability to address groups of electronic ballasts, the "Groups" work interface provides the ability to set up electronic ballast group addressing. The electronic ballast group addressing interface is shown in Figure 6.


Figure 6 group addressing interface

(15) Editing of electronic ballast group settings

Press the “Download” button to download the latest setting data of the electronic ballast. First, you can get the information about the working electronic ballast group. After pressing the "Upload" button, the corresponding electronic ballast group detection of checking/non-checking can be completed, and the loading of the new setting parameters of the corresponding electronic ballast group is completed. Note that the "Load" and "Unload" buttons of this work interface will affect the "Load" and "Unload" of all setting parameters (as shown in Figure 4).

(16) Background

Each electronic ballast in the DALI interface has its corresponding background function. The background refers to the preset lamp power. The relevant information is stored in the electronic ballast. This information can be called by relevant commands. When the electronic ballast executes a corresponding command, the electronic ballast will adjust its illuminating value to a preset value, and the background illuminating setting of each electronic ballast can be realized through the background setting interface. The "Go to Scene Level" command can be used to address the electronic ballast in all operating modes. Figure 7 shows the advanced working interface for the background setup.


Figure 7 Advanced working interface for background settings


(17) Select background


Pressing the “scene xx” button works at a pre-defined background level, and the background level selection supports all working modes. Using the “broadcast” addressing of the main interface and pressing the “scene 3” button will advance all electronic ballasts. The defined "scene 3" background level (if defined in advance).


(18) Change and load the background level


When changing the background level, you should first download the latest background level parameters, which can be achieved by pressing the "Download" button. Edit the background level you want to change and press the "Upload" button. The pre-background level setting is 255. Note that the “Upload” and “Download” buttons in this work interface will affect the loading and unloading of all set values ​​(as shown in Figure 4).


(19) Light level (lighting level)


The illuminating level interface provides a logarithmic curve of the light output % ratio, which is only valid for each electronic ballast addressing mode of operation, and Figure 8 shows the working interface of its "dimming level" curve.


Figure 8 luminous output level curve

(20) Change in update rate

The update rate "update rate" indicates the update speed of the "light-emitting level" work interface, and the update rate of the fault diagnosis interface is 5, which represents 5 times of the event timer shown in FIG.

(21) "Send Direct Commands" display work interface


Figure 9 “Send Direct Commands” shows the working interface

The "Send Direct Commands" display work interface is shown in Figure 9. The “Send Direct Commands” display work interface provides direct access to the DALI interface as detailed below.

1RS232—DALI interface preset (command 0)

Command 0 presets the RS232-DALI interface. In the case of DALI interface serialization, the interface circuit releases the control of DALI and avoids the occurrence of circuit failure. Command 0 is used to return the control information of DALI and send it back to the interface circuit.

2RS232—Status of the DALI interface (Command 1)

Command 1 is used to report the status information of the electronic ballast, bit 0 indicates a communication error in DALI, bit 1 indicates an overload fault, and these bits are cleared when power is applied and command 0 is executed.

3 information transmission (command 16)

Command 16 is used to cause the RS232-DALI interface circuit to transmit 16 bits of information to the DALI interface circuit.

4 Transfer information twice (command 17)

Command 17 is used to enable the RS232-DALI interface circuit to transmit 16 bits of information directly to DALI within 100ms. Many commands in DALI need to transmit information twice to avoid the possibility of error in information transmission.

5 transmitting and receiving information (command 18)

The command 18 is used to enable the RS232-DALI interface circuit to send 16-bit information to the DALI, and wait 10 ms to receive the feedback bit information. Many DALI commands are request-type commands, 11-bit information is feedback information, and 8 bits of the information are data information. .

4 Summary

Through the above discussion, it can be seen that the DALI dimming control protocol and software have good practicability, and are very good in applications such as building architectural lighting, theater lighting, building lighting, university lighting, warehouse lighting, and stadium lighting dimming. Application prospects, energy saving effect is obvious, it is a technology worthy of popularization and application.


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