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1、<p>  PLC in the Ice Storage Central Air-conditioning</p><p>  System of Control</p><p>  1 Introduction</p><p>  Ice storage air-conditioning is the Central Valley will be red

2、undant power grid electricity at night to form ice cold storage, electricity consumption peak during the day when the ice will melt to provide air-conditioning services. As in most parts of China's electricity at nig

3、ht is much lower than during the day, using ice cold storage central air conditioning can significantly reduce the user's operating costs. </p><p>  Ice storage central air-conditioning system configurat

4、ion of equipment than conventional air-conditioning system to increase the number and require a higher degree of automation, but it automatically to meet the requirements of the air-conditioned buildings throughout the d

5、ay under the conditions of the day will be with all the energy spent, the largest At least to save operating costs.</p><p>  2 Control system.</p><p>  Control system from the next crew (the sce

6、ne control workstations) and PC (central management workstations), with the crew using programmable logic controller (PLC) and touch screen, PC using industrial-grade computers and printers, system configuration necessar

7、y if the annex Communications equipment interface cards, modems, etc., to achieve the parameters of the storage system and automatic intelligent run. </p><p>  The crew at the scene and touch-screen system c

8、an control parameter settings and data. PC remote management and printing, which includes the crew and all the features touch screen. Following the system as a whole crew of the industrial PLC as the core, the automated

9、control. Control equipment and devices include: detection sensor components, electrical valves, converter, and so on. </p><p>  2.1 Under the machine system (Regional workstations) </p><p>  2.1

10、.1 TP21 touch-screen </p><p>  TP27 used as a color touch-screen operation panel, completely replace the conventional switch button, light, and other devices to control more interviews counters clean. And, T

11、P27 touch screen can be realized at the scene state, system settings, the model chosen, the set of parameters, fault recording, load records, time period, real-time data, load curve and reporting statistics, and other fu

12、nctions, the Chinese user interface intuitive and friendly. </p><p>  2.1.2 SIEMENS PLC </p><p>  SIMATIC S7-300 series PLC applied to all walks of life and various occasions in the detection, m

13、onitoring and control of automation, its power to both the independent operation of, or connected to a network able to achieve complex control. </p><p>  The photoelectric products with isolation, high elect

14、romagnetic compatibility; have high industrial applicability, allowing the ambient temperature of 60 ℃; has strong anti-jamming and anti-vibration and impact resistance, so in a harsh working environment has been widely

15、Applications. </p><p>  I also mean freedom of communication S7-300 type PLC' s a very unique feature, which allows S7-300-PLC can deal openly with any other communications equipment, communications cont

16、roller, or PLC S7-300 type can be defined by the user's own Communications protocol (of the agreement ASCII), the baud rate to 1.5 Mbit / s (adjustable). So that can greatly increase the scope of communications so th

17、at the control system configuration more flexible and convenient. Of any kind with a serial interface per</p><p>  When the PC offline, under the control of the next crew, the whole system can operate normal

18、ly. </p><p>  2.2 Computer System (central management workstations) </p><p><b>  2.2.1 PC </b></p><p>  PC that is by control centre, mainly by the PC and laser printer

19、components, using SIMATIC WINCC software platform, the all-Chinese interface, friendly man-machine dialogue. Managers and operators can be observed through a PC, shown in the various kinds of information to understand th

20、e present and past the ice-storage operation of the automatic control system and all the parameters, and through the mouse to print equipment management and implementation tasks. </p><p>  2.2.2 WINCC softwa

21、re platform </p><p>  WINCC software in the field of automation can be used for all the operators’ control and monitoring tasks. Can be controlled in the process of the events clearly show, and shows the cur

22、rent status and order records, the recorded data can show all or select summary form, or may be required for editing, printing and output statements and trends . </p><p>  WINCC able to control the critical

23、situation in the early stages of the report, and the signal can be displayed on the screen, can also use sound to be felt. It supported by online help and operational guidelines to eliminate failure. WINCC a workstation

24、can be devoted to the process control to the process so that important information not is shielded. Software-assisted operation strategy ensures that the process was not illegal to visit and to provide for non-industrial

25、 environment in the wrong</p><p>  WINCC is MICRSOFT WINDOWS98 or WINDOWS NT4.0 operating system, running on a PC object-oriented class 32-bit applications, OLE through the window and ODBC standard mechanism

26、, as an ideal partner to enter the communications world WINDOWS, it can be easily WINCC To integrate a company-wide data processing system. </p><p>  3 The control of ice storage system</p><p> 

27、 3.1 control objectives, scope and mainly controlled equipment </p><p>  Storage control system control Objective: To host the refrigeration, ice storage devices, plate heat exchanger, and the system pumps,

28、cooling towers, pipeline control valve system to control and adjust ice storage system of the status of the operation mode, in the most economical Circumstances to the terminal to provide a stable water temperature. At t

29、he same time, improve the level of automation and improve the management efficiency and reduce management labor intensity. </p><p>  Control of the entire ice storage systems, including the parameters of sta

30、te, state and control equipment, the main control equipment are: the status of host duplex, electrical valves, cooling towers, cooling pumps, ice storage devices, the primary glycol pump, plate heat exchanger, and Sub-gl

31、ycol pumps. </p><p>  3.2 control</p><p>  Control features include the entire ice storage system stability, economic operation with the features. </p><p>  3.2.1 Condition conversi

32、on feature </p><p>  According to the season and operation of machinery, automatic control system with the following conditions conversion features: </p><p>  a) duplex host status at the same t

33、ime cooling ice-making mode; b) duplex host the status of a separate ice-making mode; c) host and the cooling mode of ice storage devices; d) the ice-melting separate cooling mode; e) alone for the host Cold mode. </p

34、><p>  3.2.2 The status of Commitment, display and fault alarm functions </p><p>  Control system according to the schedule in chronological order, with load forecasting software, host and external

35、 control refrigeration equipment and the number of start and stop all surveillance equipment, working conditions and operating parameters, such as: - refrigeration host Commitment, status and fault alarm - host refrigera

36、tion Operating parameters - host of dry cooling protection - host for refrigeration/return water temperature, pressure, telemetry and display; - chilled water pumps s</p><p>  For cooling tower/backwater tem

37、perature control and display - for / return water temperature, pressure remote control and display - the import and export side of plate heat exchanger temperature control and display - into the ice storage devices, expo

38、rt control and temperature telemetry Show - chilled water flow control and display backwater - electric valve switch, regulating valve and-control and display - outdoor temperature and humidity control and display teleme

39、try - ice storage and display</p><p>  3.2.3 Data recording and printing </p><p>  Control system on some points need to monitor the trend recorded throughout the year; the entire control system

40、 can be in the load (including the biggest daily total load and full-load) and equipment uptime tables and charts to record for users. All monitoring points and the calculation of the data can be automatically print regu

41、larly. </p><p>  3.2.4 Manual / automatic conversion feature </p><p>  Control system configuration flexibility of manual / automatic conversion features. </p><p>  3.2.5 Optimized

42、control </p><p>  According to outdoor temperature, weather, the weather trend, history and other data automatically host the ice-melting or priority. Meet the load in the end, under the premise of daily End

43、 of cold storage, to run as little as possible hosts. Give full play to advantages of ice cold storage system, saving operating costs. </p><p>  3.2.6 Features automatic operation </p><p>  From

44、 the host computer system can work, according to a timetable for the automatic ice-making and control system operation, the status of conversion, the system for automatic fault diagnosis, and remote alarm. Touch-screen d

45、isplay system running, processes, the parameters of nodes, running records, police records. </p><p>  3.2.7 Holidays set features </p><p>  According to the timetable system can be run automatic

46、ally, but also can be pre-set holidays, ice control certificates and certificates of ice time, the system does not need the holiday season, when the supply of places to stop air-conditioning cooling. </p><p>

47、;  3.2. 8 Under the crew operating functions </p><p>  The crew operating functions are as follows: </p><p>  a) man-machine dialogue. The operator through the touch panel can be interactive, us

48、er interface completely in the culture, with tips, help, and the set of parameters, key settings, fault enquiries, history, and other functions. b) System settings. Including the operation of password settings, running s

49、et up, run the timetable set records overflow with automatic / manual / test selection, holiday settings, the system set of parameters (including the node temperature, pressure, the flow of the me</p><p>  3

50、.3 Remote Control </p><p>  Control system through telephone lines or broadband, connections with the expert system, the system operational control, parameter changes, such as data collection, the system con

51、tinuously improved and upgraded version of the software, allows users to get better service. Remote Control is aimed at users through the PSTN (public switched network transmission) of frozen remote monitoring station at

52、 different places. At the same time can achieve long-range adjustment, remote monitoring and timely m</p><p>  3.4 Systems to control </p><p>  Control system design and friendly interface, PLC

53、and touch screen can be extended, the content can be extended, the parameters can be modified through the 485 communications interface or communication protocol to achieve BAS cold storage and ice-controlled system integ

54、ration, saving investment, facilitate management. Centralized control system, reducing the driving force for counter area, the driving force for unity cabinet models, the same style, size line. System to control the foll

55、owing: </p><p>  a) sewage pump control; b) wind, ventilation control; c) live pump regulator; d) pump-time operation, detection, alarm; e) leaching pump regulator control; f) to build automatic control of l

56、ighting at night contour ; g) with low measurement, switch status detection and alarm. </p><p>  Conclusion</p><p>  Through the PLC in the ice storage air-conditioning systems, to promote the u

57、se of the PLC verify the reliability of the system features, and ensure the safe operation of the system and effective energy-saving, but also for building equipment control system controller Selection of a new way. I be

58、lieve in the near future, an increasing number of PLC systems in the ice storage air-conditioning systems in the use of the increasingly mature, in buildings and plant control systems will also play a ro</p><p

59、>  PLC在冰蓄冷中央空調系統(tǒng)控制中的應用</p><p><b>  1引言</b></p><p>  冰蓄冷中央空調是將電網夜間谷荷多余電力以冰的冷量形式儲存起來,在白天用電高峰時將冰融化提供空調服務。由于我國大部分地區(qū)夜間電價比白天低得多,所以采用冰儲冷中央空調能大大減少用戶的運行費用。</p><p>  冰蓄冷中央空調系統(tǒng)配

60、置的設備比常規(guī)空調系統(tǒng)要增加一些,自動化程度要求較高,但它能自動實現(xiàn)在滿足建筑物全天空調要求的條件下將每天所蓄的能量全部用完,最大限度地節(jié)省運行費用。</p><p><b>  2 控制系統(tǒng)結構</b></p><p>  控制系統(tǒng)由下位機(現(xiàn)場控制工作站)與上位機(中央管理工作站)組成,下位機采用可編程序控制器(PLC)與觸摸屏,上位機采用工業(yè)級計算機與打印機,系

61、統(tǒng)配置必要的附件如通信設備接口、網卡、調制解調器等,實現(xiàn)蓄冷系統(tǒng)的參數(shù)化與全自動智能化運行。</p><p>  下位機和觸摸屏在現(xiàn)場可以進行系統(tǒng)控制、參數(shù)設置和數(shù)據(jù)顯示。上位機進行遠程管理和打印,它包含下位機和觸摸屏的所有功能。整個系統(tǒng)以下位機的工業(yè)級可編程序控制器為核心,實現(xiàn)自動化控制??刂圃O備與器件包括:傳感檢測元件、電動閥、變頻器等。</p><p>  2.1 下位機系統(tǒng)(區(qū)域工

62、作站)</p><p>  2.1.1 TP21觸摸屏</p><p>  采用TP27彩色觸摸屏作為操作面板,完全取代常規(guī)的開關按鈕、指示燈等器件,使控制柜面談得更整潔。并且,TP27觸摸屏在現(xiàn)場可實現(xiàn)狀態(tài)顯示、系統(tǒng)設置、模式選擇、參數(shù)設置、故障記錄、負荷記錄、時間日期、實時數(shù)據(jù)顯示、負荷曲線與報表統(tǒng)計等功能,中文操作界面直觀友好。</p><p>  2.1.2

63、 SIEMENS可編程序控制器</p><p>  SIMATIC S7-300系列PLC適用于各行各業(yè)、各種場合中的檢測、監(jiān)測及控制的自動化,其強大功能使其無論在獨立運行中,或相連成網絡皆能實現(xiàn)復雜控制功能。</p><p>  該產品具有光電隔離,高電磁兼容;具有很高的工業(yè)適用性,允許的環(huán)境溫度達60℃;具有很強的抗干擾、抗振動與抗沖擊性能,因此在嚴酷的工作環(huán)境中得到了廣泛的應用。&l

64、t;/p><p>  自由通訊口方式也是S7-300型PLC的一個很有特色的功能,它使S7-300型PLC可以與任何通訊協(xié)議公開的其它設備、控制器進行通訊,即S7- 300型PLC可以由用戶自己定義通訊協(xié)議(例ASCII協(xié)議),波特率為1。5Mbit/s(可調整)。因此使可通訊的范圍大大增加,使控制系統(tǒng)配置更加靈活、方便。任何具有串行接口的外設,例如:打印機或條形碼閱讀器、變頻器、調制解調器(Modem)、上位PC機

65、等都可連接使用。用戶可通過編程來編制通訊協(xié)議、交換數(shù)據(jù)(例如:ASCII碼字符),具有RS232接口的設備也可用PC/PPI電纜連接起來進行自由通訊方式通訊。</p><p>  當上位機脫機時,在下位機控制下,整個系統(tǒng)能正常運行。</p><p>  2.2 上位機系統(tǒng)(中央管理工作站)</p><p><b>  2.2.1上位機</b>&

66、lt;/p><p>  上位機即圖文控制中心,主要由PC機和激光打印機組成,采用SIMATIC WINCC軟件平臺,采用全中文操作界面,人機對話友好。管理人員和操作者,可以通過觀察PC機所顯示的各種信息來了解當前和以往整個冰蓄冷自控系統(tǒng)的運行情況和所有參數(shù),并且通過鼠標進行設備管理和執(zhí)行打印任務。</p><p>  2.2.2 WINCC軟件平臺</p><p>  

67、WINCC軟件在自動化領域中可用于所有的操作員控制和監(jiān)控任務??蓪⑦^程控制中發(fā)生的事件清楚地顯示出來,可顯示當前狀態(tài)并按順序記錄,所記錄的數(shù)據(jù)可以全部顯示或選擇簡要形式顯示,可連續(xù)或按要求編輯,并可輸出打印報表和趨勢圖。</p><p>  WINCC 能夠在控制過程中危急情況的初發(fā)階段進行報告,發(fā)出的信號既可以在屏幕上顯示出來,也可以用聲音表現(xiàn)出來。它支持用在線幫助和操作指南來消除故障。某一 WINCC工作站可

68、專門用于過程控制以使那些重要的過程信息不被屏蔽。軟件輔助操作策略保證過程不被非法訪問,并提供用于工業(yè)環(huán)境中的無錯操作。</p><p>  WINCC 是MICRSOFT WINDOWS98或WINDOWS NT4。0操作系統(tǒng)下,在PC機上運行的面向對象的一流32位應用軟件,通過OLE和ODBC視窗標準機制,作為理想的通訊伙伴進入WINDOWS世界,因此WINCC可容易地結合到全公司的數(shù)據(jù)處理系統(tǒng)中。</p

69、><p>  3 冰蓄冷系統(tǒng)的控制</p><p>  3.1 控制目的、范圍及主要受控設備</p><p>  蓄冷控制系統(tǒng)控制目的:通過對制冷主機、儲冰裝置、板式熱交換器、系統(tǒng)水泵、冷卻塔、系統(tǒng)管路調節(jié)閥進行控制,調整儲冰系統(tǒng)各應用工況的運行模式,在最經濟的情況下給末端提供一穩(wěn)定的供水溫度。同時,提高系統(tǒng)的自動化水平,提高系統(tǒng)的管理效率和降低管理勞動強度。</

70、p><p>  控制范圍包括整個冰蓄冷系統(tǒng)的參數(shù)狀態(tài)顯示、設備狀態(tài)及控制,主要控制設備有:雙工況主機、電動閥、冷卻塔、冷卻水泵、蓄冰裝置、初級乙二醇泵、板式換熱器、次級乙二醇泵等。</p><p><b>  3.2 控制功能</b></p><p>  控制功能包括整個冰蓄冷系統(tǒng)穩(wěn)定、經濟運行所需的功能。</p><p>

71、  3.2.1 工況轉換功能</p><p>  根據(jù)季節(jié)和機器運行情況,自控系統(tǒng)具備以下工況轉換功能:</p><p>  a) 雙工況主機制冰同時供冷模式;b) 雙工況主機單獨制冰模式;c) 主機與蓄冰裝置聯(lián)合供冷模式;d) 融冰單獨供冷模式;e) 主機單獨供冷模式。</p><p>  3.2.2 工況的啟停、顯示和故障報警功能</p><

72、p>  控制系統(tǒng)按編排的時間順序,結合負荷預測軟件,控制制冷主機及外圍設備的啟停數(shù)量及監(jiān)視各設備之工作狀況與運行參數(shù),如:制冷主機啟停、狀態(tài)及故障報警;制冷主機運行參數(shù);制冷主機缺水保護;制冷主機供/回水溫度、壓力遙測和顯示;冷凍水泵啟停、狀態(tài)及故障報警;乙二醇泵啟停、狀態(tài)及故障報警;冷卻水泵啟停、狀態(tài)及故障報警;壓差旁通管的壓差測量與顯示;冷卻塔風機啟停、狀態(tài)及故障報警;</p><p>  冷卻塔供/回

73、水溫度控制與顯示;供/回水溫度、壓差遙測控制與顯示;板式換熱器側進出口溫度控制與顯示;蓄冰裝置進、出口溫度遙測控制與顯示;冷凍水回水流量控制與顯示;電動閥開關、調節(jié)與閥位控制與顯示;室外溫濕度遙測控制與顯示;蓄冰量測量與顯示;末端冷負荷控制。</p><p>  3.2.3 數(shù)據(jù)的記錄和打印功能</p><p>  控制系統(tǒng)對一些需要的監(jiān)測點進行整年趨勢記錄,控制系統(tǒng)可將整年的負荷情況(包

74、括每天的最大負荷和全日總負荷)和設備運轉時間以表格和圖表記錄下來,供使用者使用。所有監(jiān)測點和計算的數(shù)據(jù)均能自動定時打印。</p><p>  3.2.4 手動/自動轉換功能</p><p>  控制系統(tǒng)配置靈活的手動/自動轉換功能。</p><p>  3.2.5 優(yōu)化控制功能</p><p>  根據(jù)室外溫度、天氣預報、天氣走勢、歷史記錄等

75、數(shù)據(jù)自動選擇主機優(yōu)先或融冰優(yōu)先。在滿足末端負荷的前提下,每天使用完儲存的冷量,盡量少地運行主機。充分發(fā)揮冰儲冷系統(tǒng)優(yōu)勢,節(jié)約運行費用。</p><p>  3.2.6 全自動運行功能</p><p>  系統(tǒng)可脫離上位機工作,根據(jù)時間表自動進行制冰和控制系統(tǒng)運行、工況轉換、對系統(tǒng)故障進行自動診斷,并向遠方報警。觸摸屏顯示系統(tǒng)運行狀態(tài)、流程、各節(jié)點參數(shù)、運行記錄、報警記錄等。</p&g

76、t;<p>  3.2.7 節(jié)假日設定功能</p><p>  系統(tǒng)可根據(jù)時間表自動運行,同時也可預先設置節(jié)假日,控制儲冰量和儲冰時間,使系統(tǒng)在節(jié)假日時對不需要供應空調的場所停止供冷。</p><p>  3.2.8 下位機操作功能</p><p>  下位機操作功能如下:</p><p>  a) 人機對話。操作人員可通過觸摸

77、面板進行人機對話,操作界面完全中文化,具有提示、幫助、參數(shù)設置、密匙設置、故障查詢、歷史記錄等功能。</p><p>  b) 系統(tǒng)設置。包括操作口令設置、運行設置、運行時間表設置、記錄溢出處理、自動/手動/測試選擇、節(jié)假日設置、系統(tǒng)參數(shù)設置(包括各節(jié)點溫度、壓力,各介質的流量,儲冰量,制冰速率,融冰速率,閥門開度,末端負荷等。)</p><p>  c) 故障記錄、運行記錄、歷史記錄等。

78、</p><p><b>  3.3 遠程監(jiān)控</b></p><p>  控制系統(tǒng)通過電話線或寬帶網,與專家系統(tǒng)連接,對系統(tǒng)進行運行監(jiān)控、參數(shù)修改、數(shù)據(jù)采集等,使系統(tǒng)不斷完善和軟件版本升級,讓用戶得到更好的服務。遠程監(jiān)控的目的是用戶可以通過PSTN(公共交換傳輸網)對冷凍站進行異地遠程監(jiān)控。同時也可以實現(xiàn)遠程調試、遠程適時監(jiān)控和在線維護等,從而大大減輕工程人員的工作

79、強度,降低工程成本。</p><p>  3.4 系統(tǒng)擴展控制</p><p>  控制系統(tǒng)設計界面友好,PLC和觸摸屏均可擴展,內容可擴展、參數(shù)也可修改,通過485通訊接口或通信協(xié)議實現(xiàn)BAS與冰儲冷自控系統(tǒng)一體化,節(jié)約投資、方便管理。系統(tǒng)集中控制,減少了動力柜占地面積,又使動力柜型號統(tǒng)一、式樣相同、大小一致。系統(tǒng)擴展控制如下:</p><p>  a)污水泵自動

80、控制;b)風、排風控制;c)活水泵穩(wěn)壓控制;d)防水泵定時運行、檢測、報警; e)淋水泵穩(wěn)壓控制;f)筑物夜間輪廓照明自動控制;g) 低配計量、開關狀態(tài)檢測、報警。</p><p><b>  4 結語</b></p><p>  通過PLC在冰蓄冷空調系統(tǒng)的推廣運用,驗證了PLC系統(tǒng)的可靠性特點,保證了系統(tǒng)的安全運行和有效節(jié)能,同時也為樓宇設備控制系統(tǒng)的控制器選型提

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