【 Weak current college 】 building automatic control system design and problems (2)

III. building automatic control system design should note the following issues
1. determination of the scope of management
On buildings of various types of equipment to monitor, control, measurement, should be running a secure, reliable, saving energy and manpower. Management scope to combine developers or owners of the investment, but also the local administrative bodies for specific requirements. Example: some parts of the power requirements, and distribution systems can be integrated into the system, BAS BAS system can be set to display, record, measure and alert, you can control the system breaker closing, trip; at the same time requirements for fire alarm systems, linked system must be independent, in BAS system can display, record, you can control, etc. These views are not the same as the place to be, with the development of science and technology, will gradually change. Now intelligent building engineering design, BAS system management scope includes: refrigeration, air conditioning, heating, ventilation, drainage dynamics, transformation and distribution system, lighting system, elevator and escalator surveillance system, parking management systems, etc.
2. the controller I/O points and interface technology
Determine the point of control to reference the intelligent building design standards "BAS system category a, class b, class c design standards. To tie in with the professional engineers, reference the professional drawings and design requirements, jointly study to determine the locus of control, monitoring points table.
Usually the building equipment monitoring system size is used to measure the "numbers", 400 points following is a small system, 400 ~ 700 points for medium-sized systems, greater than 700 points for large systems. Number of points not only reflects the size of the system, and directly related to the system of investment and the cost. In the design phase, the first job should be points of the system. System of points and a number of devices based on the entire system and each device monitoring, control and measuring how much of the functionality, designers must determine, and related subjects such as air conditioning, water, strong power designers work closely with, according to the function, in order to accurately determine the entire construction equipment monitoring system of total points.
In the construction equipment monitoring system project design, due to the specialization and professional cross-cutting issues, determine the points and how to deal with the point of the external connection interfaces are often not well coordinated, resulting in system design, project implementation difficulties. As the system's designers should be coordinated with other professional designers and learn about other specialized equipment such as air conditioning, water supply and drainage, electrical and other basic principle and process requirements. In recent years, with building equipment monitoring system engineering design practice and summary, many product suppliers and agents are successively provides design selection guide, to engineering point selection, determine the points and points of connection interface technology design is of great help. The Ministry of construction are organizations prepared to adapt construction equipment monitoring system using the "national building standard design Atlas", in order to resolve and partial solution engineering design and construction of installation issues, provides an effective method. By Tianjin Institute is responsible for the preparation of the "air-conditioning automatic control" standard design concentrated water chillers, heat exchangers, air handlers, air supply unit, VAV unit, such as air conditioning equipment involved in the monitoring system of monitoring, control and measurement point selection, there are enumerated type. Design combined with specific project will be able to easily determine the number of points and point the device type. By the Ministry of construction design Institute and other units of the "common fan control circuit" (99D37S) and "common pump control circuit" (01D303-3) and "level measuring device is installed" (99SD767), the National Atlas of building standard design, fan, pump, liquid level control, and other commonly used device control circuit and the computer data to set I/O controller and DDC controller, interfaces, how to connect, turn signals and remote transmission has said.

In the second part by the nuclear industry and Research Institute is responsible for the preparation of the "6-10 kV substation and secondary connection (direct action)" (01D203-3) figure set, 6-10 kV switchgear, transformer, signals and DC power supply unit into the building equipment monitoring system to monitor, control, measurement, and other interface connections, while deepening the design-time, in the second standard wiring diagrams out monitoring, control and measurement contacts to connect terminals, if it is a measurement signal must be approved by the transmitter and then received a DDC controller i/o interfaces. Construction equipment monitoring system for design, construction workers can benefit from these "national building standard design Atlas" good system points and point type. With electrical officers complete electromechanical secondary wiring deepen design, solve interface connection.
3. Central action and communication network of the correct configuration
Only the central action and communication network is configured properly, in order to achieve the building equipment run centralized monitoring and management of basic service features. The central station of device configuration to be taken into account to the system's size and the conditions for investment, without corruption large perfection, should be applied to meet the system requirements.
In the "civil construction electrical design specifications" section in chapter 26 on Central action and communication network configuration, the following requirements:
(1) meet the needs of the centralized monitoring and control;
(2) the selected network structures and the monitored system to adapt;
(3) for risk diversification to minimize the failure of the affected surface, in particular, large systems, the use of distributed systems;
(4) reducing the initial investment;
(5) the system must be easy to implement an Extender.
Domestic building equipment monitoring system on the market, many domestic and foreign products, the system's network have different, but the system is constituted mainly by the Ethernet and fieldbus components, most products are in compliance with the BACnet and Lonworks protocol standards for the different manufacturers of products connected and extensions, as well as intelligent building system integration.
At the completion of a good building equipment monitoring system, in addition to the note above the three-part work, systems planning, energy saving consciousness must be underlined. In General, a building equipment monitoring system for the total investment is about buildingInvestment of 1% to 2%, recycling investment period in 3 to 5 years. If investment of hundreds and even thousand million completed equipment monitoring system, to the role of energy efficiency, has failed to recover the investment cost, this is not what we invest in building equipment monitoring system. Energy saving is one of the long-term basic policy, but now the building equipment monitoring system, part or a significant part of the project focus on this point, failure to fully exploit the potential of the system energy-saving features
4. conclusions
To fully exploit the capabilities of the building automation system, you need to design elaborate detailed design demonstration, unified planning, engineering and construction units elaborate construction, more system integrator with a strong sense of responsibility, from the user point of view, for each project, select a suitable for its own feature configuration, party a will as soon as possible with the appropriate engineering and technical personnel, to join the project implementation, so as to contribute to the project acceptance and system operation and maintenance, thus truly effective in building automation system, create a good social and economic benefits.
In addition, although to electrical engineers or control engineers thoroughly assess the relevant professional knowledge is difficult, but in order to facilitate and equipment, and other related professional engineers communication so that the design of control system meets the requirements of a normal and reasonable working conditions, necessary to understand some of the conceptual knowledge, promptly eliminate current design industry professional links between "grey areas" is the key to the success or failure of the system.