英文文献PLC in the ice storage central air.docx

1、英文文献PLC in the ice storage central airPLC in the ice storage central air-conditioning system of control 1 Introduction In PLC in 30 years which developed, it passes through develops unceasingly, already could unify simulates I/O, the network corresponds as well as uses new programming standard like

2、IEC 61131-3. However, engineers only must use digital I/O and few simulations I/O number as well as simple programming skill on potential 80% industrial application. PLC has been widely used in all industrial sectors. According to The United States market information World PLC and software market re

3、port, in 1995 the global software PLC and its economies of scale of about 5 billion US dollars 5. As electronic technology and the development of computer technology, Because uses traditional the tool to be possible to solve 80% industrial application, like this intensely needs to have low cost simp

4、le PLC; Thus promoted the low cost miniature PLC growth, it has the useful trapezoidal logical programming digital I/O. However, this has also created the discontinuity in the control technology, on the one hand 80% application need to use the simple low cost controller, but on the other hand other

5、20% application then have surpassed the function which the tradition control system can provide. Engineer is developing these 20% application to need to have the higher circulation speed, the senior control algorithm, the more simulations function as well as can well and the enterprise network integ

6、ration.In 80 and the 90s, these must develop 20% application engineers had considered uses PC in the industry control. PC provides the software function may carry out the senior task, provides the rich programming and the user environment, and the PC COTS part enables control engineer the technology

7、 which develops unceasingly to use in other applications. These technologies including floating point processor; High speed I/O main line, like PCI and ethernet; Fixed data memory; software development kit. Moreover PC also can provide the incomparable flexibility, highly effective software as well

8、as senior low cost hardware. Ice thermal storage air conditioning is the central power grid could be redundant-night ice electricity in the form of cold storage, in the daytime peak hours of electricity to provide air-conditioning services melting ice. As most parts of our country at night than duri

9、ng the day much lower price, using ice cold storage central air-conditioning can greatly reduce user operating costs. Ice storage central air-conditioning system configuration of equipment than conventional air conditioning system to increase some, require a higher degree of automation, but it autom

10、atically to meet the requirements of the air-conditioned buildings all day every day under the conditions of the energy he has exhausted all, the biggest limits to save operating costs. the PLC functions are greatly enhanced, with the following characteristics:(1) high reliability. PLC benefited fro

11、m the high-reliability hardware and software on a series of anti-jamming measures and the cycle of its special scanning methods of work. (2) with rich I / O interface module. PLC for different industrial field signal and the corresponding I / O modules and industrial devices or equipment at the scen

12、e of a direct connection. In addition to improving performance, it also has a variety of man-machine dialogue interface modules to the industrial composition of local area networks, it also multiple communications network interface module.(3) modular structure. To meet the needs of various industria

13、l control, in addition to a small PLC unit, the vast majority of PLC are modular structure. PLC various components, including the CPU, power supply, I / O, etc. is modular in design from the rack and cables will connect each module, the systems size and function in accordance with the needs of users

14、 of its own portfolio. (4) easy to learn programming. Most of the PLC programming relay control circuit similar to the ladder diagram form, the user, do not have computer expertise, it is easy to general engineering and technical personnel understand and master. (5) Installation is simple and easy m

15、aintenance. PLC does not require specialized equipment room in a variety of industrial environments can be directly run. Various modules are run and fault indication devices, user-friendly understanding of the operation and find fault. The modular structure, so any failure of a module, users can rep

16、lace the module, allowing the system to rapidly resume operation.Second, the characteristics and Application of industrial PC 2 control system The control system consists of the crew (Floor Control Workstation) and PC (central management workstation), with the crew using programmable logic controlle

17、r (PLC) with the touch screen, PC using industrial-grade computers and printers, system configuration necessary if the annex communications equipment interfaces, network interface cards, modems and so on, to achieve the parameters of the storage system and intelligent automatic operation. Under the

18、crew at the scene and touch-screen systems can control, parameter settings and data. PC remote management and print, it contains the crew and all of the features touch screen. Following the system as a whole crew of industrial programmable logic controller as the core, to achieve automatic control.

19、Control equipment and devices including: detection sensor components, electric valves, converter, etc. Under the 2.1-Systems (Regional workstations) 2.1.1 TP21 touch screen TP27 used as a color touch-screen operator panel, completely replace conventional button, lights device, the control cabinet in

20、terviewed more tidy. Moreover, TP27 touch screen at the scene showed that the state can be realized, system settings, mode selection, parameter setting, fault recording, record load, time-of-day, real-time data, load curve and reporting statistics, and other functions, Chinese intuitive and friendly

21、 user interface. 2.1.2 SIEMENS PLC SIMATIC S7-300 Series PLC applied to all walks of life, all kinds of occasions in the detection, monitoring and control automation, its powerful features to both operate independently, or linked to a network able to achieve complex control functions. The product fe

22、atures photoelectric isolation, and high electromagnetic compatibility; high industrial applicability, allowing the ambient temperature of 60 ; has a strong anti-jamming and anti-vibration and impact resistance, in the harsh environment of the work has been widely applications. I also means freedom

23、of communications S7-300 PLC, a very unique features, it makes S7-300 PLC with any communication protocol can open other equipment, communications controller, or PLC S7-300 can be defined by the users themselves communications protocols (for example ASCII protocol), baud rate of 1.5 Mbit / s (adjust

24、able). Thus the scope of the communications can be greatly increased, the control system configuration more flexible and convenient. Any serial interface with peripherals, such as: printer or bar code readers, the drive, a modem (Modem), the upper PC can be connected to the machine. Users can progra

25、m to develop communication protocol to exchange data (such as: ASCII character code), RS232 interface with the equipment available PC / PPI free cable linking communications communication. Chip and Chip Holderslntegrated Circuis are usually called Ics or chips. Thay are complex circuits, which have

26、benn etched onto tiny chips of semiconductor(silicon). The chip is packaged in a plastic holder with pins spaced on a 0.1(2.54mm)grid, which will fit the holes on stipboard. Very fine wires inisde the package link the chip to the pins.1) Pin numbersThe pins are numbered anti-clockwise around the IC(

27、chip) starting near the notch or dot. It shows the numbering for 8-pin and 14-pin Ics, but the principle is the same for all sizes.2) Chip holders(DIL sockets)ICs(chip)are easily damageded by heat when soldering and their short pins cannot be protected with a heat sink. Instead we use a chip holder,

28、 strictly called a DIL socket(DIL=Dual In-Line), which can be safely soldered onto the circuit board. The chip is pushed into the holder when all solding is complete.Chip holders are only nedded when solding so they are not used on breaboards.Commercially produced circuit boards often have chips sol

29、dered directly to the board without a chip holder ,usually this is done by a machine which is able to work very quickly .Please donnot attemp to do this yourself because you are likely to destory the chip and it will be different to remove without damage by de-soldering.3) Removing a chip from its h

30、older4) If you need to remove a chip it can be gently prized out of the holder with a small flat-blade screwdriver. Carefully lever up each end by inserting the screwdriver blade between the chip and its holder and gently twisting the screwdrive. Take care to statre lifting at both ends before you a

31、ttempt to remove the chip,otherwise you will bend and possibly break the pins.5） Bipolar Integrated Circuits MOS Integrated CircuitsHistorically, bipolar Integrated Circuits used to be much more popular than MOS Integrated Circuits,particularly for small-sace logic Circuits. There were two major rea

32、sons for this: first, bipolar-junction transistors originally could be manufactured more reliably than MOS transistors,and second , they were faster, As the reliabitity of MOS transistors improved, and as integrated Circuits became more complex , which made the lower power and small size of MOS logic more important, the popularity of BJT logic decreased, however, BJT technology is still popular for the highest frequency logic circuits. When the PC offline, under the control of the next crew, the entire system can operate normally. PC System 2.2 (central management workstation) PC 2.2.1