Intelligent Building Theory of Building Automation System – Intelligent Building
HC intelligent home network Building automation system, also known as building automation system (BuildingAutomationSystem referred to as BAS), is an integral part of intelligent building, its task is the building's energy use, environmental, traffic and safety monitoring, control, etc., in order to ensure a safe and reliable, but also save energy, but also a comfortable and pleasant working or living environment.
2 building automation system components and basic functions
Building automation systems typically include air conditioning, water supply and drainage, power supply, lighting, elevators, fire safety and prevention and other subsystems. According to our industry standards, BAS can be divided into device management and control subsystem operation and fire prevention and safety subsystems, as shown. Normal circumstances, this two subsystems with Naru BAS should consider if the fire and security prevention Ziji Tong independent setting, and BAS control center should establish a communications link to the disaster occurs, can achieve Caozuo accordance with the agreement the right to transfer, for integrated coordination and control.
Building automation system's basic functions can be summarized as follows:
(1) automatic monitoring and control of various electrical and mechanical equipment, the stop, display or print the current operating state.
(2) automatic detection, display, print a variety of electrical and mechanical equipment operating parameters of trends or historical data.
(3) according to external conditions, environmental factors, the change automatically adjust the load of equipment, so that is always running in top condition.
(4) monitoring and timely processing of all accident emergencies.
(5) to achieve a variety of electrical and mechanical equipment on building a unified management, coordination and control.
(6) Energy Management: Water, electricity, gas, etc. metering and charging, developing energy management automation.
(7) Equipment Management: including device files, equipment operation and equipment maintenance management reports.
3 the principle of building automation control system
Floor control system used in modern control theory is based on Distributed Computer Control System, also known as distributed control system (Distributedcontrolsystems referred to as DCS). It is characterized by a "centralized management decentralized control," that is charged with distribution of equipment in the field office of the micro-computer control (DDC) to complete device charged with the task of real-time detection and control, centralized control of computer to overcome the risks of high lack of centralized control and conventional single instrument limitations. Installed at the central control room of the central management computer has a CRT display, print output, rich software management and strong digital communications capabilities, able to complete the concentration operation, display, alarm, control and optimization tasks such as printing, to avoid the spread of conventional instrumentation control After the man-machine contact difficulties, the shortcomings can not be unified management to ensure the equipment running in top form.
Here are distributed control systems with several concepts.
3.l direct digital control system (DDC)
Direct digital control system (DirectDigitalControl referred to as DDC) shown in Figure 2. Computer through the analog input channels (AI) and digital input channels (DI) real-time data collection, and then calculated according to certain rules, and finally the control signals, and through the analog output channels (AO) and the switch output channel (DO ) direct control of the production process. So DDC system is a closed-loop control system is a computer in the industrial production process, the most common way of an application.
DDC system control computer to undertake the task, which required real-time, high reliability and adaptability.
3.1.1 Composition of direct digital control system
Direct digital control system consists of the process input channel, process control computer, the process of output channels of three parts.
Process input channels from the analog input and digital input of two parts. Analog input channels from the transmitter, the sampling switch, amplifier, A / D converter and interface circuit. One is the role of the transmitter signal will be converted into the standard non-power electrical signals can be temperature, pressure, flow transformed into 0-10mA or 4-20mA DC signal, it is through A / D converter to achieve. ? Digital input channels from the switch contacts, photoelectric coupler and interface circuit, reflecting the production process on / off state of the contact signal, through the optocoupler and the interface circuit transformation into a digital signal sent to the computer.
Direct commitment to the process control computer operations and control tasks, first of all input channels through the process of collecting the parameters of the object and signals, then the scheduled control law (such as PID) for operation, and then send control signals to the controlled object, and through the output channels such as direct control valve actuator.
Process output channel from the analog output and digital output of two parts. The former control of the computer output of digital signals into analog voltage or current signals, through the amplifier to drive control valve actuators to achieve control of the production process. This part of the interface circuit, D / A converter, amplifier and actuator component. The latter switches the computer output signal, by the amplifier to drive solenoid valve and relay actuator, which consists of interfaces electrical, optical coupler, amplifier and actuator component.
3.1.2 direct digital control system the basic algorithm
In accordance with the deviation ratio (P), integral (I) and differential (D) control, a continuous system technology is mature, the most widely used as a basic rule, the discrete PID control law and on computer , can easily use the mature technology has been accumulated, and can be charged with the mathematical model or parameter is not very clear circumstances, and after online tuning to achieve satisfactory results. Therefore, the law regulating discrete analog digital PID algorithm, computer control of industrial processes have been widely adopted system, a DDC system, the basic algorithm.
Digital PID control algorithm, analog PID controller formula for the ideal
Type of e (t)?? Deviation (set value and the difference between the actual output value)
U (t)?? Control volume Kp?? Scaling factor Ti an integral time constant Td?? Differential time constant Written in the form of transfer function
In order to implement on a computer, you must be a continuous form of differential equations into a discrete form of differential equations. Set for the sampling period (compared with the system time constant, T is small enough), k is sampling number (k = 0,1,2, … …), can be calculated and rectangular plot to replace the differential difference
Type of e (k)?? The first k
I am an expert from yaisu.com, while we provides the quality product, such as 3D Cinema System , Motion Theater Chair, 3D Cinema System,and more.
Processing your request, Please wait....
