Realization of Integration of Intelligent Lighting Control System and Building Automation System

With the enhancement of energy saving consciousness and comfort requirements, intelligent lighting control system and building automatic control system are more and more used in public buildings. At the beginning of the design, designers need to consider: what form of intelligent lighting control system can achieve better data interaction and linkage with building automatic control system? In small and medium-sized public buildings, the control of lighting system is simple and the circuit is few, which is not a problem, but in large or ultra-large public buildings, the control is complex and the circuit is numerous, this problem is worth discussing.

1 The four stages of intelligent lighting control system

Intelligent lighting control system is generally composed of signal input, control unit and system host. Signal input is to convert external control signals into system signals, including all kinds of control panels or touch screens, intelligent sensors, remote controls, etc. The control unit executes system commands to realize lighting control, including all kinds of control modules, dimming modules, etc. The system host includes monitoring software and communication interface.

Intelligent lighting control system mainly adopts bus structure and has four development stages (as shown in Figure 1 ~ 3).

The first generation and the second generation of intelligent lighting control system are centralized control system, each module and control panel only as the executive mechanism, passively execute the instructions issued by the main control CPU, all the control panel needs a separate dedicated power supply for power supply, the smooth operation of the system depends on the CPU greatly. With the increasing scale of modern single buildings, the control system network is also increasing. Once the main control CPU runs unstable, it is easy to cause the paralysis of the whole system or a whole branch system, which brings huge hidden dangers to the smooth operation and maintenance of the whole building.

On the basis of summarizing and learning the advantages and disadvantages of the first two generations of intelligent lighting control system, the third generation of distributed intelligent lighting control system, using a fully distributed structure (distributed control system structure), each control module, control panel has its own CPU, can realize the field control, central control computer centralized control, control system reliability, scalability, compatibility are improved.

The fourth generation of distributed intelligent lighting system, in addition to the distributed structure, each control module, control panel has a built-in processor and memory, with data copy/equipment self-recovery technology, individual excellent brands can also through the module to the bus power supply, again improve the stability and reliability of the system, and more convenient maintenance, easier to use.

2 DALI System

At present, the Lighting control system of some manufacturers uses DALI system, DALI (Digital Addressable Lighting Interface) is the abbreviation of digital addressable lighting Interface, is a data transmission protocol, it defines the communication mode between the electronic ballast and the equipment controller.

DALI is an international standard for digital lighting control and is not owned by any one company. DALI provides a simple means of digital communication, simple and flexible controls, the ability to mix and match DALI compliant LED lighting and ballast lighting from different manufacturers, and the ability to have multiple controllers within a system that can store data separately. The DALI system has the features of digital addressable, multi-channel control, self-on-off control, and bidirectional control.

The DALI system has many advantages, but I don't think it is likely to be used on a large scale anytime soon, mainly for the following reasons:

(1) The initial investment cost is too high, and the cost recovery cycle is too long. Few units in China can be compared with petrochina (petrochina Tower is the largest application case of DALI system in the world).

(2) Technical aspects need to be improved (for example, many lamps are more than one light source. Currently, ballasts in the DALI system are usually at most one to three. If a lamp has more than a dozen light sources or even more, it will be equipped with many ballasts, which will greatly increase the engineering cost).

In my opinion, in order to popularize DALI system on a large scale, the control strategy should be adjusted, which should not be a simple single light control, but a combination of grouping, partition and single light control. A lighting circuit can take more than a group of lamps, a group of lamps set a ballast that address (at present, some products can not meet this requirement, manufacturers need to improve), so that greatly reduce the number of addresses, also greatly reduce the cost of the project.

Intelligent lighting control system and building automatic control system integration

In the early stage, contactor was used to realize lighting control in building automatic control system. Due to the disadvantages of inconvenient scene control and poor flexibility, contactor was basically replaced by intelligent lighting control system with the development of intelligent lighting control system.

At present, intelligent lighting control system and building automatic control system integration mainly through OPC (OLE for process control) and protocol conversion interface two ways. OPC mode (the structure form is shown in Figure 4) is easy to realize the integration of the two systems, but in practical engineering application, there will be data omission problem, and the data loss cannot be found. If the building automatic control system does not give instructions to the lighting system, only accept the data of the lighting control system, and display the working state in the upper computer, it is safe to use this way; If the building automation system needs to issue instructions to the lighting control system, it is not very safe to use OPC mode. The main concern is the impact of data omission on the system.

By means of protocol conversion interface or dry spring contact interface, the lighting control system can be reliably connected with building control, fire control, security and other systems. According to specific needs, the entire lighting system can cooperate with other systems to control each lighting control point and a specific lighting control area. Because of its high reliability and cost performance, this method is worth promoting in large public buildings.

Figure 5(a) shows the traditional way of adding a gateway between two servers. Figure 5(b) shows the way of transforming products from different manufacturers into unified communication protocols, which is suitable for large or ultra-large buildings with numerous control devices. This way is very convenient for system integration.

4 Case Analysis

The construction scale of the military Museum renovation and expansion project is about 150,000 square meters, with two underground floors, four above-ground floors and seven local floors. It is a typical large public building, with a total of 18 electrical shafts designed.

In accordance with modern and digital museum standards to carry out the design, adhere to the "advanced technology, appropriate advance" design concept. In order to facilitate user management and strengthen energy conservation and environmental protection measures, intelligent lighting control system is adopted in the lighting part to realize the combination of centralized control and local control. The plumbing equipment in this project is numerous and scattered, so the building automatic control system adopts three-layer distributed control system. The whole system relies on the internal LAN and adopts the digital transmission mode. The system structure is shown in Figure 6.

Each electrical shaft is equipped with a network controller for the lighting control module and DDC to transform the equipment of different manufacturers into a unified communication protocol and realize the networking of the whole system relying on the internal LAN. This scheme has the following advantages:

(1) High degree of system integration. The network controller is used to convert the products of different manufacturers into a unified communication protocol, which is well composed of a system and realizes the interoperability between the building automatic control system and the lighting control subsystem.

(2) The system wiring is convenient. The system relies on the internal LAN to transmit data, and each electrical shaft has a comprehensive wiring system, so it is no longer necessary to lay a separate communication line.

(3) High system reliability. Each device in the system has a unique IP address, which reduces the error rate.

(4) The system has good universality and strong operability. Because the system relies on the internal LAN, the uplink port of all suppliers is set to the standard Ethernet, which is conducive to future maintenance and replacement of standard products, reduces the dependence on a single supplier, and provides strong operability in system integration.

5 Conclusion

The integration mode of intelligent lighting control system and building automatic control system can be selected according to the complexity of building control, OPC mode and protocol conversion interface can be adopted. For public buildings with simple control and fewer loops, the two systems can be integrated by OPC. Large or super-large public buildings with complex control and many loops are suitable for integration using protocol conversion interface.

Building Electrical General Atlas. Building Equipment Monitoring 09BD10. Beijing: China Architecture and Building Press, 2009; 9