Technology is the lifeblood of an enterprise, but production safety is the first priority of an enterprise. So before entering the technical knowledge, let us mention that the outline content of participating in the government safety production conference today:
Doing a good job of safe production in an enterprise is the top priority of an enterprise. No matter how good an enterprise's production is, safety accidents occur frequently and safety hazards can be seen everywhere. This enterprise is definitely not a good enterprise. The safety production slogans we mention every day all put "safety" in the first place, which fully illustrates the important role of safety in enterprise production. Our business managers should do a lot of work around the theme of "safe production". They must grasp the main contradictions without leaving the slightest safety hazard; how to carry out these tasks is the most reasonable and reliable, and it is worthy of the business managers. In-depth research and discussion.
Now we enter today's subject dali switching module technical knowledge.
The dali dimming control method of fluorescent lamps is improved with the continuous innovation and development of electronic ballast technology. The early dimming of fluorescent lamps with iron core ballasts generally uses the output of thyristor cutting-edge phase control dimmers to directly control the output of fluorescent lamps. Brightness and ballast are just a load connected in series in the fluorescent lamp loop. This dimming method has low efficiency, poor performance, and narrow dimming range. It is rarely used at home and abroad.
In recent years, with the emergence of high-frequency electronic ballasts, the DALI lighting control technical performance of ballasts has changed. Many companies have gradually introduced high-frequency dimmable electronic ballasts with high efficiency, good performance, wide dimming range and high intelligence. Fluorescent lamp ballast, this kind of ballast as the ECG (electronic DALI control device) of fluorescent lamp has become the mainstream product of fluorescent lamp dimming control.
Divided by the number of control lines of the ballast, there are two, three, and four lines. The most widely used product on the market is the "four-wire control" ballast. The dimming controller is the ballast through two 220V main power lines. The converter provides power support, and two ultra-low voltage control lines can interface with the ballast to achieve various functional controls such as switching and dimming.
According to the nature of the DALI control interface control signal, it can be divided into three dali device types:
1. 1-10V analog interface.
2. Digital signal interface (DSI).
3. Digital Addressable Light Interface (DALI).
Some of these DALI lighting control&dali switch interfaces have been formulated as the international industrial standard IEC929, and some have been recognized by their peers.
In 1984, Philips first introduced the first commercial series of electronic ballasts. In 1994, it formulated the industrial standard IEC929 for 1-10V analog interface control ballasts. Soon after, Tridonic launched a digital control using Manchester Code. Interface (DSI) ballasts make it easier to control fluorescent lamps to connect with digital dimming controllers, thereby expanding the scope of application. Dynalite has developed various types of electronic ballasts for 1-10V and DSI high-frequency dimming. There are two types of fluorescent lamp dimming controllers. At present, many application projects, including some domestic projects, use these two control interfaces.
The DALI lighting control signal of the 1-10V interface is a DC analog quantity, and the signal polarity is divided into positive and negative. The brightness of the fluorescent lamp is adjusted according to the linear rule. Once the control signal is triggered during dimming, the ballast starts the fluorescent lamp and is first excited to ignite. Full brightness, and then adjust to the corresponding brightness according to the control quantity requirements. According to the IEC929 standard, the maximum working current of each ballast is 1mA.
The DALI lighting control signal of the DSI interface (Digital Signal interface) ballast is a digital signal Manchester code (manchester Code), the signal has no polarity requirement, the signal is transmitted on the control line and the synchronization method is relatively reliable, and the dimming is based on the exponential function. After the ballast is triggered, the brightness of the fluorescent lamp can be adjusted from 0 to the brightness specified by the control signal. This is very suitable for the dimming application of the theater fluorescent lamp. In addition, DSI can also use signal commands in the electronic ballast The 220V main power supply entering the ballast is controlled internally. When the fluorescent lamp is turned off and extinguished, the ballast can automatically cut off the 220V main power supply to save energy consumption. It can also save the main power line connection of the switch controlled by the dimmer, and directly connect with the 220V main power line, which can also save the system cost.
DALI Digital Addressahle Lighting Interface (Digital Addressahle Lighting Interface) ballast is currently the latest type of dimmable fluorescent lamp ballast. In 1999, Philips, ORSAM, Tridonic and other companies jointly formulated the DALI industrial standard and included it in IEC929 , To ensure that the DALI equipment produced by different manufacturers can all be compatible.
DALI is a data transmission protocol. It defines the communication method between electronic ballasts and device controllers. It is not a new bus, but it supports open systems. The original goal of designing and applying DALI is to optimize an intelligent A type of lighting control system, trying to develop a simple system structure; easy to install; easy to operate, good-functioning lighting control system, can be used for lighting control in a room, can also interface with the building management system BMS, DALI system and BMS or EIB; LON bus system is different. It is not expanded into a system with various complex control functions, but only as a lighting control subsystem, integrated into the BMS through a gateway interface, and can accept BMS control commands or recycle The operating state parameters of the subsystem.
The DALI ballast that integrates the combination switch and dimming control is connected to the 2-core control line through the DALI interface, and each ballast (as Slave) can be addressed separately through the fluorescent lamp dimming controller (as Master) , Which means that the dimming controller can adjust the brightness of each fluorescent lamp connected to the same control line separately. A single-segment DALI data control line can address 64 ballasts separately, each ballast 16 lighting scenes can be set in the device. The same ballast can also be grouped in one group or in multiple groups. The maximum grouping group is 16, so a DALI system can control up to 1000 ballasts.
The addressing of the DALI ballast is completed during system debugging. The address generation adopts the random number method. After each debugging, the address of any ballast on the control line is uncertain, so when a certain ballast in the system When the device fails and needs to be replaced, it is not simply a replacement, but the address of the newly replaced ballast must be the same as the address that was replaced. At present, the address of the ballast must be reprogrammed with special debugging equipment. Address, otherwise an address conflict will occur.
Comparison of the performance of three different dali switch interface electronic ballasts
dali device Type dali Control cable Control switch signal Control signal polarity requirement The brightness of the fluorescent lamp is at 0% after the start of the fluorescent lamp can be separately addressed Dimming characteristics Dimming range 220V main power supply voltage control
DALI 2-wire digital Manchester encoding No Yes Yes Index 1-100% Switchable control in the ballast
DSI 2-wire Digital Manchester code No Yes No Index 1-100%
3-100% switchable control in the ballast
1-10V 2-wire 1-10V analog quantity Yes No No Linearity 1-100%
20-100% controlled by dali dimming controller
The main features of DALI interface forming the lighting control system are:
1) The communication structure is simple and reliable. The DALI interface communication protocol is composed of 196 bits. The first bit is the start bit, the second to the 9th bit are the address bit, the 10th to the 17th bit is the data, and the 18th and 19th bit stop Bit, using Manchester encoding, the transmission rate is 1200 baud, and the high level on the control line is 16V. Each controller on the control line acts as a master in the communication, and the ECG like a ballast on the control line only responds to the command of the master to act as a SLAVE. The system has a distributed intelligent function. As shown in Figure 1.
2) The installation is simple and convenient. There are two main power lines and two control lines to install the DALI interface. There are no special requirements for wires and no polarity requirements during installation. Only the main power line and the control line are required to be isolated. The control line does not need to be shielded. Note that when the current on the control line is 250mA and the line length is 300 meters, the voltage drop does not exceed 2V.
3) The operation is simple and easy. The DALI ballast is intelligent inside, which can automatically handle filament preheating, ignition, dimming, switching, fault detection and other functions. It is very user-friendly and the user does not need to understand it deeply It can be operated and controlled, such as sending a command to change the current scene, and each relevant ballast calculates the dimming rate according to the difference between the current brightness and the required brightness of the scene to achieve that all ballasts are synchronized to the required scene brightness. If you send a query command, you can retrieve the operating status and parameters of each ballast.
DALI was originally designed to be used for lighting control in a room. Now various devices controlled by DALI interface have come out one after another. The control function is also expanding and improving, and the scale of control is also expanding. Dynalite recently developed and produced DBC-120 DALI It is a DALI fluorescent lamp dimming controller, which is equivalent to a gateway, through which multi-segment DALI subsystems can be connected into a large-scale lighting control system. The backbone of this control system can run a protocol higher than DALI , Such as the DyNet2 network protocol, which can connect 4194240 devices at most. The DBC-120 DALI controller has two addressing modes, namely 6-bit short address addressing and 24-bit long address addressing.
6-bit short address addressing is suitable for general small systems. Up to 64 devices can be connected to the network, and each device has a unique address. Since this 6-bit address is generated by a random number, there may be two devices in a system. The same address causes a control conflict, and the probability of a 24-bit long address generating the same long address is very low.
In addition, in a short address system with multiple ballasts, due to the slow network speed, for example, when these ballasts are turned off to on, the first ballast ignites the fluorescent lamp until the last ballast ignites the fluorescent lamp. There will be a delay effect that can be clearly felt by people, called "Mexican Wave" (Mexican Wave edge effect). If there are few ballasts, this phenomenon will not exist. Long address addressing can prevent this edge effect. , But the long address requires each ballast to have a group number and scene information, and a fixed fade (gradual) rate parameter should be preset during debugging.
dali driver Control performance comparison of DALI different addressing modes
Mode Maximum number of connected nodes per network DALI network power supply Main power relay switch for energy saving Number of groups per network Number of scenes per network Variable fade rate of scenes
Original DALI mode 64 Requirement Requirement 16 16 None
DBC-120DALI group and scene image long address mode *4194240 Built-in Built-in 16 16 None
DBC-120DALI short address mode *4194 240 Built-in Built-in 64 170 Yes
4,194,240 nodes can be configured on the DyNet2 network.
Nowadays, DALI interface is not only used for fluorescent lamp ballasts, various halogen lamps, electronic transformers of LED lamps also use DALI interface; control equipment also includes: photoelectric sensor, radio receiver, relay switch input interface; various The key control panel, including the LED display panel, has a DALI interface. In addition, it can also convert DSI to DALI or from 1-10V to DALI, as well as the RS232 and DALI conversion controller that communicates with the PC. This will make the application of DALI more As it spreads, the controller has expanded from the smallest office to a multi-room office building, from a single store to a large hotel.
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