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計(jì)數(shù)器底座注塑件注塑模具設(shè)計(jì)【計(jì)算器外殼】【一模兩腔】,計(jì)算器外殼,一模兩腔,計(jì)數(shù)器,底座,注塑,模具設(shè)計(jì),計(jì)算器,外殼
Proceedings of the World Congress on Engineering 2009 Vol I
WCE 2009, July 1 - 3, 2009, London, U.K.
New Cooling Channel Design for I njection
Moulding
A B M Saifullah, S.H. Masood and Igor Sbarski
Abstract— Injection moulding is one of the most versatile and
important operation for mass production of plastic parts. In this
process, cooling system design is very important as it largely
determines the cycle time. A good cooling system design can
reduce cycle time and achieve dimensional stability of the part.
This paper describes a new square sectioned conformal cooling
channel system for injection moulding dies. Both simulation and
experimental verification have been done with these new cooling
channels system. Comparative analysis has been done for an
industrial part, a plastic bowel, with conventional cooling
channels using the Moldflow simulation software.
Experimental verification has been done for a test plastic part
with mini injection moulding machine. Comparative results are
present ed based on temperature distribution on mould surface
and cooling time or freezing time of the plast ic part. The results
provide a uniform temperature distribution with reduced
freezing time and hence reduction in cycle time for the plastic
part.
Index Terms—Conformal cooling channel, Cycle time
Moldflow, Square shape.
I. INTRODUCTION
Injection moulding is a widely used manufacturing process
in the production of plastic parts [1]. The basic principle of
injection moulding is that a solid polymer is molten and
injected into a cavity inside a mould which is then cooled and
the part is ejected fro m the machine. Therefore the main
phases in an injection moulding process involve filling,
cooling and ejection. The cost-effectiveness of the process is
mainly dependent on the time spent on the moulding cycle in
which the cooling phase is the most significant step. Time
spent on cooling cycle determines the rate at which parts are
produced. Since, in most modern industries, time and costs
are strongly linked, the longer is the time to produce parts the
more are the costs. A reduction in the time spent on coo ling
the part would drastically increase the productio n rate as well
as reduce costs. So it is important to understand and optimize
the heat transfer process within a typical moulding process.
The rate of the heat exchange between the injected plastic and
the mo uld is a decisive factor in the economical performance
of an injection mould
A B M Saifullah is a research doctoral student at Industrial Research Institute
Swinburne (IRIS), Swinburne University of Technology, Melbourne,
Australia (e-mail- msaifullah@swin.edu.au), also Member, IAENG.
S. H. Masood is a Professor of Mechanical & Manufacturing Engineering at
Faculty of Engineering and Industrial Sciences, Swinburne University of
Technology, Melbourne, Australia. (Corresponding author, ph:+61-3-9214
8260, fax: +61-3-9214 5050, e-mail: smasood@swin.edu.au)
Dr Igor Sbarski is a Senior Lecturer at Faculty of Engineering and Industrial
Sciences, Swinburne University of Technology, Melbourne,
Australia.(e-mail: isbarski@swin.edu.au ).
3
.Heat has to be taken away from the plastic material until a
stable state has been reached, which permits demolding. The
time needed to accomplish this is called cooling time or
freezing time of the part. Proper design of cooling system is
necessary for optimum heat transfer process between the
melted plastic material and the mould. Traditionally, this has
been achieved by creating several straight holes inside the
mould core and cavity and then forcing a cooling fluid (i.e.
water) to circulate and conduct the excess heat away from the
molten plastic. The method s used for producing these holes
rely on the conventional machining process such as straight
drilling, which is incapable of producing complicated
contour-like channels or anything vaguely in 3D space.
An alternative method of coo ling system that co nforms or
fits to the shape of the cavity and core of the mould can
provide better heat transfer in injection moulding process, and
hence can result in optimum cycle time. This alternative
method uses contour-like channels of different cross-section,
constructed as close as po ssible to the surface of the mould to
increase the heat absorption away from the molten plastic.
This ensures that the part is cooled uniformly as well as more
efficiently. Now-a-days, with the advent of rapid p rototyping
technology such as Direct Metal Deposition (DMD), Direct
Metal Laser Sintering (DMLS) and many advanced computer
aid ed engineering (CAE) software, more efficient co oling
channels can be designed and manufactured in the mould with
many complex layout and cross-sections[2,3,4].
This paper presents a square section conformal co oling
channel (SSCCC) for injection moulding die. Simulation has
been done for an industrial p lastic part, a circular plastic
bowel for these SSCCC and compared with conventional
straight cooling channels (CSCC) with Moldflow Plastic
Inside (MPI) software. Comparative experimental
verification has also been performed with SSCCC and CSCC
die for a circular shape test part with mini injectio n moulding
machine for two plastic materials. Result shows that SSCCC
die gives better cooling time and temperature distribution than
that of CSCC dies.
II. DESIGN OF THE PART AND MOULDS
A. Part design
The part circular plastic bowl made of polyprop ylene (PP)
thermoplastic, as shown in Fig 1(a) has been designed with
Pro -Engineer CAD software. It was then exported to IGES
(Initial Graphics Exchange Specification) file surface
model to impo rt in MPI for analysis. Material volume of
the plastic part is 177.90cm and its weight is 162.3 gm.
Experimental test part as shown in Fig 1(b) has also been
d esigned with Pro-Engineer software. Experimental
ISBN: 978-988-17012-5-1
WCE 2009
Proceedings of the World Congress on Engineering 2009 Vol I
WCE 2009, July 1 - 3, 2009, London, U.K.
verification has b een done with two types of plastic
materials, PP and ABS (Acrylonitrile Butadiene Styrene).
Test part volume was 8.8 cm3, and part weight for ABS and
PP were 8.68 gm and 8.13gm respectively.
(a)
(b)
(a) (b)
Fig-1 CAD model of (a) Circular plastic bowel, (b) Test part.
B. Mould Design
Mould design has been done using Pro/Moldesign module
of the Pro /Engineer system. This mould is then manufactured
with Computer Numerical Control (CNC) machine. The
mould shown in Fig 2 has two parts, the core and the cavity.
Square section conformal cooling channel (SSCCC) has been
produced around the cavity by CNC machining of one half of
the channel on cavity part and the other half on the core part.
Both halves are then joined with screws and sealed with liquid
gasket (Permatex) to avoid water leakage.
Fig-2 Assembly CAD model of mould with core (top )
and two cavity parts.
III. ANALYSIS AND RESULTS
MPI simulation software has been used for part analysis
[5]. Analysis sequence was flow-cool-warp. Polyprop ylene
plastic material has been used for analysis. Comparative
analysis has been done with conventional straight coo ling
channel (CSCC) and SSCCC. The diameter of CSCC was 12
mm and the length of SSCCC section size was 12 mm (Fig 3).
Fusion meshing with global edge length of 0.995 cm has been
used . The numbers of mesh elements used were 12944 and
12291 for CSCC and SSCCC respectively.
3
Fig-3 Analysis setting in MPI (a) CSCC (b) SSCCC
Both cases used cooling medium as normal water of 25°C.
Reynolds number was 10000, melting temperature was 230
°C. Comparative analysis result from MPI as shown in Fig 4
shows that SSCCC shows better temperature distribution and
(a) (b)
Fig-4 Comparative freezing or cooling time (a) CSCC
(b) SSCCC.
less part freezing time than CSCC. In case of CSCC, most of
the part cools in about 24 second except the top few areas,
while on the other hand SSCCC diagram shows that it is less
than 20 seconds. And also CSCC shows the time to freeze
range to be 0.4 6-93.7sec and SSCCC shows this to be
0.3-87.15sec. So, using SSCCC, 5 second of cooling time has
been reduced which is 3 5% reduction of cooling time.
IV. EXPERIMENTAL VERIFICATION AND RESULTS
Experimental verification has been done with a circular
shap e plastic test part using the machined mould as shown in
Fig 5. Part diameter was 40 mm and thickness was 7 mm.
The mould dimension was 10x10x2.5 cm . Mould material
was mild steel. Experiment has been done with a mini
(a) (b)
Fig-5 (a) Mild steel Core (left) and cavity with SSCCC
(b) CSCC of mild steel.
ISBN: 978-988-17012-5-1
WCE 2009
Proceedings of the World Congress on Engineering 2009 Vol I
WCE 2009, July 1 - 3, 2009, London, U.K.
injection moulding machine of TECHSOFT mini moulder
(Fig 6). Two thermocouples TC08 K type of PICO
technology have been used to measure temperature of top and
bottom surface of the test part. Melting temperature was
250°C fo r both ABS and PP. Normal water has been used as
a cooling medium, room temperature has been measured as 25
°C, so is cooling water. Cooling channel diameter was 5 mm
for CSCC and SSCCC section size was 5 mm. With two
thermocouples, surface temperature of the test part has been
measured for every second.
Fig-8 Comparative temperature plot for PP
In experimental tests, twenty samp le test parts have been
produced for ABS and PP material for experimental
verification and in every case almost the same data has been
found. Fig 9 shows the sample test parts in ABS and PP,
which have been produced fo r experimental verification.
Fig-6 Experimental setup for test injection moulding,
left: mini moulder, right: temperature outp ut in PC.
Fig
7
and
Fig
8
show the comparative temperature
distribution for top and bottom surface of the plastic parts for
30 second.
Fig-9 Sample test part prod uced for experimental verification
Left: ABS right: PP plastic.
V. CONCLUSION
The cooling process is one o f the most important sub processes
in
injection
moulding
because
it
normally
accounts
for
approximately half of the total cycle time and affects directly the
Fig-7 Comparative temperature plot for ABS
From Fig 7 it is noted that for the ABS plastic, using
SSCCC, the top face and bottom face of test part cooled
earlier than that with CSCC. In case of SSCCC, maximum top
and bottom surface temperature recorded at particular time
immediately after injection were 53.36 °C and 52.1°C. After
30 second, this temperature reduced to 42.47 °C and 43.07
°C, whereas, for CSCC they were 53.24, 52.01 and 47.47,
47.72 °C. So in average, 4 to 5 °C reduction in temperature
happens using the SSCCC. Similar results also have been
found when using PP as the part material. From Fig 8, it can
be shown that using SSCCC, about 2 to 3 °C reduction in
temperature can be possible.
shrinkage, bending and warp age of the moulded plastic product.
Therefore, designing a go od cooling channel system in the mould is
crucial since it influences the production rate and quality. The
results of MPI simulation and experimental verification show that
using square shape conformal cooling channels gives up to 35%
reduction in cooling time and 20% of the total cycle time can b e
obtained, thus greatly improving the production rate and the
production quality of injection moulded parts.
ACKNOWLEDGMENT
These authors are grateful to Mrs. Meredith and Phil Watson
of Faculty of Engineering and Industrial Science,
Swinburne University of Technology for their technical
support for die making with CNC machining.
ISBN: 978-988-17012-5-1
WCE 2009
Proceedings of the World Congress on Engineering 2009 Vol I
WCE 2009, July 1 - 3, 2009, London, U.K.
REFERENCES
[1 ] D.V. Rosato, D.V. Rosato and M.G. Rosato, Injection
Moulding Handbook-3rd ed , Boston, Kluwer Academic Publishers, (2003).
[2 ] X. Xu, E. Sach and S.Allen, The Design of Conformal
Cooling Channels In Injection Moulding Tooling,Polymer Engineering and
Science, 4, 1, pp 1269-1272, (2001).
[3] D.E. Dimla, M. Camilotto, and F. Miani: Design and optimization of
conformal cooling channels in injection moulding tools, J. of Mater.
Processing Technology, 164-165, pp 1294-1300, (2005).
[4] A B M Saifullah and S. H. Masood, Optimum cooling channels design and
Thermal analysis of an Injection moulded plastic part mould, Materials Science
Forum, Vols. 561-565, pp. 1999-2002, (2007).
[5] A B Saifullah, S. H. Masood and Igor Sbarski, cycle time
optimization and part quality improvement using novel cooling channels in plastic
injection moulding. ANTEC@NPE 2009, USA.
ISBN: 978-988-17012-5-1
WCE 2009
畢 業(yè) 設(shè) 計(jì)(論文)
外 文 翻 譯
英文翻譯題目一： Application_of_PLC_in_the_Elevator_Control_System_of_Intelligence_Building
英文翻譯題目二：Elevator System Based on PLC
學(xué) 院 名 稱： 機(jī)械工程學(xué)院
專 業(yè)： 材料成型及控制工程
班 級(jí)： 成型102班
姓 名： 何足道 學(xué)號(hào) 10403070234
指 導(dǎo) 教 師： 陳永清
2014年2月8日
英文題目一
Application_of_PLC_in_the_Elevator_Control_System_of_Intelligence_Building
翻譯內(nèi)容
指導(dǎo)教師評(píng)語
指導(dǎo)教師簽字
年 月 日
英文題目二
Elevator System Based on PLC
翻譯內(nèi)容
指導(dǎo)教師評(píng)語
指導(dǎo)教師簽字
年 月 日
PLC在智能建筑的電梯控制系統(tǒng)中的應(yīng)用
摘要：本文主要討論了智能建筑系統(tǒng)的一個(gè)子系統(tǒng)：電梯控制系統(tǒng)。 PLC干擾能力強(qiáng)等特點(diǎn)，使電梯行業(yè)一個(gè)又一個(gè)的應(yīng)用PLC在電梯控制系統(tǒng)，以取代傳統(tǒng)的電梯控制系統(tǒng)中正在使用的繼電器。 PLC在電梯控制系統(tǒng)中的應(yīng)用降低了故障率，有效地提高了電梯運(yùn)行的可靠性與安全性。系統(tǒng)的結(jié)構(gòu)也很簡(jiǎn)單、緊湊。它的工作原理是：現(xiàn)場(chǎng)控制信息從用戶輸入設(shè)備發(fā)送到PLC，然后控制柜需要根據(jù)系統(tǒng)要求發(fā)出控制信號(hào)驅(qū)動(dòng)設(shè)備。從而電梯可以根據(jù)控制要求來執(zhí)行相應(yīng)的行動(dòng)。 本文選擇了OMRON公司的C200HE系列PLC，引進(jìn)部分信號(hào)轉(zhuǎn)播的電梯控制系統(tǒng)和解釋功能的控制柜，最后是介紹自動(dòng)化編程。模擬實(shí)驗(yàn)闡述了該設(shè)計(jì)方法是可行的。PLC在電梯控制系統(tǒng)中的應(yīng)用是一種有效的方法，它可以使行業(yè)管理中心的人員在控制中心遠(yuǎn)程監(jiān)控和控制電梯，通過以太網(wǎng)與智能建筑行業(yè)管理系統(tǒng)或?qū)Ｓ镁W(wǎng)絡(luò)的連接，如經(jīng)度工程。電梯的工作狀態(tài)也可以及時(shí)關(guān)注。這不僅能實(shí)現(xiàn)科學(xué)集中管理的電梯，而且還可以降低電梯的維護(hù)費(fèi)用等，這是智能樓宇的電梯控制系統(tǒng)的發(fā)展方向之一。
Ⅰ、介紹
在20世紀(jì)80年代第一個(gè)智能大廈已在美國(guó)完成，然后智能建筑已被全世界廣泛注意。隨著社會(huì)的發(fā)展，智能建筑的概念已經(jīng)提出了不同的含義。早期智能建筑被認(rèn)為等同于智能大廈，但現(xiàn)在智能建筑不僅包括智能化豪宅，也涉及到智能住宅小區(qū)。本文主要討論了智能建筑系統(tǒng)的一個(gè)子系統(tǒng)：電梯控制系統(tǒng)。
在智能住宅小區(qū)中，企業(yè)信息管理系統(tǒng)主要負(fù)責(zé)有關(guān)日常生活事情，例如監(jiān)督區(qū)設(shè)備，車輛管理，處理危急情況等。對(duì)于智能住宅小區(qū)來說電梯監(jiān)控系統(tǒng)也是需要的。如何使人們感到安全，穩(wěn)定舒適和如何節(jié)約能源資源、保護(hù)環(huán)境等是電梯控制系統(tǒng)的基本要求.。
PLC是一種常見的工業(yè)控制裝置。它是一種特殊的工業(yè)控制計(jì)算機(jī)，具有完善的功能和簡(jiǎn)單的框架。PLC干擾能力強(qiáng)等特點(diǎn)，使得電梯行業(yè)一個(gè)又一個(gè)的在電梯控制系統(tǒng)中應(yīng)用PLC，以取代傳統(tǒng)電梯控制系統(tǒng)中正在使用的繼電器。PLC在電梯控制系統(tǒng)中的應(yīng)用降低了電梯的故障率，有效地提高了電梯運(yùn)行的可靠性與安全性。本文主要討論電梯控制系統(tǒng)的工作原理，以及系統(tǒng)的軟件和硬件實(shí)現(xiàn)方法等。
Ⅱ、電梯控制系統(tǒng)的工作原理
下圖為電梯控制系統(tǒng)的硬件結(jié)構(gòu)圖。
圖1電梯控制系統(tǒng)硬件結(jié)構(gòu)圖
電梯控制系統(tǒng)的工作原理表述如下：現(xiàn)場(chǎng)控制信息從用戶輸入設(shè)備發(fā)送到PLC，然后控制柜需要根據(jù)系統(tǒng)要求發(fā)出控制信號(hào)驅(qū)動(dòng)設(shè)備。從而電梯可以根據(jù)控制要求來執(zhí)行相應(yīng)的行動(dòng)。有速度反饋系統(tǒng)的裝置，其中采用測(cè)速發(fā)電機(jī)提供了電梯速度，一般是安裝在尾部的牽引電動(dòng)機(jī)。所以這是一個(gè)反饋控制系統(tǒng)，它可以提高系統(tǒng)的控制精度。
Ⅲ、該控制系統(tǒng)硬件配置
在電梯的控制系統(tǒng)中是沒有必要做接口電路的。我們所要做的是發(fā)送信號(hào)到PLC的數(shù)字信號(hào)輸入端子，包括內(nèi)部和外部呼叫信號(hào)，樓層位置檢測(cè)信號(hào)，限制信號(hào)的位置，打開和關(guān)閉電梯門信號(hào)等的直流電源提供給PLC，可以用作指示燈電源。PLC輸出點(diǎn)可以直接用來控制傳感器用于電機(jī)的正轉(zhuǎn)，反轉(zhuǎn)，停止和控制各段速度等。OMRON公司的C200HE系列PLC已被選定作為主要控制配置，其中主要是根據(jù)輸入/輸出點(diǎn)和用戶的程序長(zhǎng)度。另一方面，我們也認(rèn)為，在未來系統(tǒng)的功能可以擴(kuò)大。C200HE系列PLC，其完善的功能和強(qiáng)大的可靠性，目前能夠滿足這些要求。
此外，除了PLC，系統(tǒng)的主控制裝置：輸入和輸出設(shè)備，需要在電梯控制系統(tǒng)中。
圖2中所示為一部分信號(hào)連線的電梯電氣控制系統(tǒng)。
控制柜是控制中心，從中我們可以發(fā)出各種控制命令?？刂乒裢ǔＪ前惭b在電梯房里。電氣設(shè)備和信號(hào)系統(tǒng)，例如接觸器，繼電器，電容，電阻，整流器和變壓器等，都是集中在控制柜中。電源控制柜的進(jìn)口電梯前室的主要力量。這股力量也被引入到控制面板中的軟電纜里，并與各控制按鈕連接。電源線是由控制柜傳遞給牽引電動(dòng)機(jī)，其他的控制線和信號(hào)線分別發(fā)送到每個(gè)地板接線盒，以形成電梯的執(zhí)行電路。
圖2的電梯控制系統(tǒng)的信號(hào)連線
圖3子程序證監(jiān)會(huì)：主叫方在一樓，電梯在三樓
Ⅳ、程序設(shè)計(jì)
該設(shè)計(jì)包括兩部分：硬件和軟件。硬件設(shè)計(jì)是軟件的基礎(chǔ)?？紤]到控制的需求是相對(duì)復(fù)雜的，我們?cè)O(shè)計(jì)的程序，根據(jù)該控制功能分開。此外，我們遵循的原則如下：當(dāng)電梯上升，必須先執(zhí)行上升后執(zhí)行其他要求，當(dāng)電梯下降，必須執(zhí)行下降后執(zhí)行其他要求。在設(shè)計(jì)過程中采用順序功能圖（SFC）。它是一種專門用于工業(yè)順序控制。證監(jiān)會(huì)的方法可以很詳細(xì)的描述系統(tǒng)的工作過程。例如，有一個(gè)三層智能建筑，子程序的調(diào)用，電梯在一樓到三樓，如圖 3。
當(dāng)所有SFC制定好和I / O地址列表給出了，我們可以將SFC配對(duì)梯形圖（LD）?？紤]到時(shí)間和鎖定對(duì)方的嚴(yán)格要求，我們引進(jìn)工作位來記住工作步驟。我們可以寫出位控制程序，它可以把每一個(gè)步驟連接在一起使上一步驟作為下一步驟的約束條件。因此，實(shí)際的輸出是這些工作步驟的邏輯組合。
Ⅴ、結(jié)論
目前，系統(tǒng)程序經(jīng)過完全的調(diào)試。模擬實(shí)驗(yàn)表明，該設(shè)計(jì)方法是可行的。PLC在電梯控制系統(tǒng)中的應(yīng)用是一種有效的方法，它可以使行業(yè)管理中心的人員在控制中心遠(yuǎn)程監(jiān)控和控制電梯，通過以太網(wǎng)與智能建筑行業(yè)管理系統(tǒng)或?qū)Ｓ镁W(wǎng)絡(luò)的連接，如經(jīng)度工程。電梯的工作狀態(tài)也可以及時(shí)關(guān)注。這不僅能實(shí)現(xiàn)科學(xué)集中管理的電梯，而且還可以降低電梯的維護(hù)費(fèi)用等，這是智能樓宇的電梯控制系統(tǒng)的發(fā)展方向之一。
參考文獻(xiàn)
[1]梁劍氣，段振剛，何煒?；赑LC的電梯遠(yuǎn)程監(jiān)控系統(tǒng)（中國(guó)）通訊的實(shí)現(xiàn)[J]北京工商大學(xué)學(xué)報(bào)2003,21（2）:18-21
[2]馬紅倩，張欣應(yīng)用PLC在大廈電梯控制系統(tǒng)（中國(guó)）[J]。中華遼寧高職學(xué)報(bào)2002,4（5）：86-88。
[3]崔廣元， PLC在電梯控制中的應(yīng)用. （中國(guó)）[J] - 東北電力技術(shù)2003，（7）：50-52。
作者簡(jiǎn)歷
第一作者是目前在太原理工大學(xué)的老師。她目前的研究興趣包括信號(hào)處理，智能控制等。
第二作者是目前正作為一個(gè)老師在太原理工大學(xué)從事科學(xué)和技術(shù)相關(guān)課程的教學(xué)。她目前的研究興趣包括電信，智能控制等。
PLC控制下的電梯系統(tǒng)
由繼電器組成的順序控制系統(tǒng)是最早的一種實(shí)現(xiàn)電梯控制的方法。但是，進(jìn)入九十年代，隨著科學(xué)技術(shù)的發(fā)展和計(jì)算機(jī)技術(shù)的廣泛應(yīng)用，人們對(duì)電梯的安全性、可靠性的要求越來越高，繼電器控制的弱點(diǎn)就越來越明顯。
電梯繼電器控制系統(tǒng)故障率高，大大降低了電梯的可靠性和安全性，經(jīng)常造成停梯，給乘用人員帶來不便和驚憂。且電梯一旦發(fā)生沖頂或蹲底，不但會(huì)造成電梯機(jī)械部件損壞，還可能出現(xiàn)人身事故。
可編程序控制器(PLC)最早是根據(jù)順序邏輯控制的需要而發(fā)展起來的，是專門為工業(yè)環(huán)境應(yīng)用而設(shè)計(jì)的數(shù)字運(yùn)算操作的電子裝置。鑒于其種種優(yōu)點(diǎn)，目前，電梯的繼電器控制方式己逐漸被PLC控制所代替。同時(shí)，由于電機(jī)交流變頻調(diào)速技術(shù)的發(fā)展，電梯的拖動(dòng)方式己由原來直流調(diào)速逐漸過渡到了交流變頻調(diào)速。因此，PLC控制技術(shù)加變頻調(diào)速技術(shù)己成為現(xiàn)代電梯行業(yè)的一個(gè)熱點(diǎn)。
1. PLC控制電梯的優(yōu)點(diǎn)
(1)在電梯控制中采用了PLC，用軟件實(shí)現(xiàn)對(duì)電梯運(yùn)行的自動(dòng)控制，可靠性大大提高。
(2)去掉了選層器及大部分繼電器，控制系統(tǒng)結(jié)構(gòu)簡(jiǎn)單，外部線路簡(jiǎn)化。
(3)PLC可實(shí)現(xiàn)各種復(fù)雜的控制系統(tǒng)，方便地增加或改變控制功能。
(4) PLC可進(jìn)行故障自動(dòng)檢測(cè)與報(bào)警顯示，提高運(yùn)行安全性，并便于檢修。
(5)用于群控調(diào)配和管理，并提高電梯運(yùn)行效率。
(6)更改控制方案時(shí)不需改動(dòng)硬件接線。
2.電梯變頻調(diào)速控制的特點(diǎn)
隨著電力電子技術(shù)、微電子技術(shù)和計(jì)算機(jī)控制技術(shù)的飛速發(fā)展，交流變頻調(diào)速技術(shù)的發(fā)展也十分迅速。電動(dòng)機(jī)交流變頻調(diào)速技術(shù)是當(dāng)今節(jié)電、改善工藝流程以提高產(chǎn)品質(zhì)量和改善環(huán)境、推動(dòng)技術(shù)進(jìn)步的一種主要手段。變頻調(diào)速以其優(yōu)異的調(diào)速性能和起制動(dòng)平穩(wěn)性能、高效率、高功率因數(shù)和節(jié)電效果，廣泛的適用范圍及其它許多優(yōu)點(diǎn)而被國(guó)內(nèi)外公認(rèn)為最有發(fā)展前途的調(diào)速方式
交流變頻調(diào)速電梯的特點(diǎn)
⑴ 能源消耗低
⑵ 電路負(fù)載低，所需緊急供電裝置小
在加速階段，所需起動(dòng)電流小于2.5倍的額定電流。且起動(dòng)電流峰值時(shí)間短。由于起動(dòng)電流大幅度減小，故功耗和供電纜線直徑可減小很多。所需的緊急供電裝置的尺寸也比較小。
⑶ 可靠性高，使用壽命長(zhǎng)。
⑷ 舒適感好
電梯運(yùn)行是跟隨最佳給定的速度曲線運(yùn)行的。其特性可適應(yīng)人體感受，并保證運(yùn)行噪聲小，制動(dòng)平穩(wěn)
⑸ 平層精度高
⑹ 運(yùn)行平穩(wěn)無噪聲
在轎廂內(nèi)，機(jī)房?jī)?nèi)及鄰近區(qū)域確保噪聲小。因?yàn)槠湎到y(tǒng)中采用了高時(shí)鐘頻率。始終產(chǎn)生一個(gè)不失真的正弦波供電電流。電動(dòng)機(jī)不會(huì)出現(xiàn)轉(zhuǎn)距脈動(dòng)。因此，消除了振動(dòng)和噪聲。
3.電梯控制技術(shù)
所謂電梯控制技術(shù)是指電梯的傳動(dòng)系統(tǒng)及操縱系統(tǒng)的電氣自動(dòng)控制。作為我國(guó)20世紀(jì)70年代電梯的主要標(biāo)志是交流雙速電梯。其調(diào)速方法是采用改變電梯牽引電動(dòng)機(jī)的極對(duì)數(shù)，兩種或兩種不同級(jí)對(duì)數(shù)的繞組，其中極數(shù)少的繞組稱為高速繞組，極數(shù)多的繞組稱為低速繞組。高速繞組用于電梯的起動(dòng)及穩(wěn)速運(yùn)行，低速繞組用于制動(dòng)及電梯的維修。
80年代初，VVVF變頻變壓系統(tǒng)控制的電梯問世。它采用交流電動(dòng)機(jī)驅(qū)動(dòng)，卻可以達(dá)到直流電動(dòng)機(jī)的水平，目前控制速度已達(dá)6米/秒。它的體積小，重量輕，效率高，節(jié)省能源等幾乎包括了以往電梯的所有優(yōu)點(diǎn)。是目前最新的電梯拖動(dòng)系統(tǒng)。
電梯在垂直運(yùn)行過程中，有起點(diǎn)站也有終點(diǎn)站。對(duì)于三層樓以上的建筑物的電梯，起點(diǎn)站和終點(diǎn)站之間還沒有?？空荆瘘c(diǎn)站設(shè)在一樓，終點(diǎn)站設(shè)在最高樓。設(shè)在一樓的起點(diǎn)站稱為基站，起點(diǎn)站和終點(diǎn)站稱為兩端站，兩端站之間稱為中間站。
各站廳外設(shè)有召喚箱，箱上設(shè)置有供乘用人員召喚電梯用的召喚按鈕或觸鈕，一般電梯在兩端站的召喚箱上各設(shè)置一只按鈕或觸鈕。中間層站的召喚箱各設(shè)置兩只按鈕或觸鈕。對(duì)于無司機(jī)控制的電梯，在各層站的召喚箱上均設(shè)置一只按鈕或觸鈕。而電梯的轎廂內(nèi)部設(shè)置有（雜物電梯除外）操縱箱。操縱箱上設(shè)置有手柄開關(guān)或與層站對(duì)應(yīng)的按鈕或觸鈕，操縱箱上的按鈕或觸鈕城內(nèi)指令按鈕或觸鈕。外指令按鈕或觸鈕發(fā)出的電信號(hào)稱為外指令信號(hào)，內(nèi)指令按鈕或觸鈕發(fā)出的電信號(hào)成為內(nèi)指令信號(hào)。20世紀(jì)80年代中期后，觸鈕已被微動(dòng)按鈕所取代。
作為電梯基站的廳外召喚箱，除設(shè)置一只召喚按鈕或觸鈕外，還設(shè)置一只鑰匙開關(guān)，以便下班關(guān)電梯時(shí)。司機(jī)或管理人員把電梯開到基站后，可以通過專用鑰匙扭動(dòng)該鑰匙開關(guān)。把電梯的廳門關(guān)閉妥當(dāng)后，自動(dòng)切斷電梯控制電源或動(dòng)力電源。
4. PLC控制電梯的設(shè)計(jì)
隨著城市建設(shè)的不斷發(fā)展，高層建筑不斷增多，電梯在國(guó)民經(jīng)濟(jì)和生活中有著廣泛的應(yīng)用。電梯作為高層建筑中垂直運(yùn)行的交通工具已與人們的日常生活密不可分。實(shí)際上電梯是根據(jù)外部呼叫信號(hào)以及自身控制規(guī)律等運(yùn)行的，而呼叫是隨機(jī)的，電梯實(shí)際上是一個(gè)人機(jī)交互式的控制系統(tǒng)，單純用順序控制或邏輯控制是不能滿足控制要求的，因此，電梯控制系統(tǒng)采用隨機(jī)邏輯方式控制。目前電梯的控制普遍采用了兩種方式，一是采用微機(jī)作為信號(hào)控制單元，完成電梯信號(hào)的采集、運(yùn)行狀態(tài)和功能的設(shè)定，實(shí)現(xiàn)電梯的自動(dòng)調(diào)度和集選運(yùn)行功能，拖動(dòng)控制則由變頻器來完成；第二種控制方式用可編程控制器（PLC）取代微機(jī)實(shí)現(xiàn)信號(hào)集選控制。從控制方式和性能上來說，這兩種方法并沒有太大的區(qū)別。國(guó)內(nèi)廠家大多選擇第二種方式，其原因在于生產(chǎn)規(guī)模較小，自己設(shè)計(jì)和制造微機(jī)控制裝置成本較高；而PLC可靠性高，程序設(shè)計(jì)方便靈活，抗干擾能力強(qiáng)、運(yùn)行穩(wěn)定可靠等特點(diǎn)，所以現(xiàn)在的電梯控制系統(tǒng)廣泛采用可編程控制器來實(shí)現(xiàn)。
5.電梯控制系統(tǒng)特性
在電梯運(yùn)行曲線中的啟動(dòng)段是關(guān)系到電梯運(yùn)行舒適感指標(biāo)的主要環(huán)節(jié)，而舒適感又與加速度直接相關(guān)，根據(jù)控制理論，要使某個(gè)量按預(yù)定規(guī)律變化必須對(duì)其進(jìn)行直接控制，對(duì)于電梯控制系統(tǒng)來說，要使加速度按理想曲線變化就必須采用加速度反饋，根據(jù)電動(dòng)機(jī)的力矩方程式:M—MZ=ΔM=J（dn/dt），可見加速度的變化率反映了系統(tǒng)動(dòng)態(tài)轉(zhuǎn)距的變化，控制加速度就控制系統(tǒng)的動(dòng)態(tài)轉(zhuǎn)距ΔM=M—MZ。故在此段采用加速度的時(shí)間控制原則，當(dāng)啟動(dòng)上升段速度達(dá)到穩(wěn)態(tài)值的90%時(shí)，將系統(tǒng)由加速度控制切換到速度控制，因?yàn)樵诜€(wěn)速段，速度為恒值控制波動(dòng)較小，加速度變化不大，且采用速度閉環(huán)控制可以使穩(wěn)態(tài)速度保持一定的精度，為制動(dòng)段的精確平層創(chuàng)造條件。在系統(tǒng)的速度上升段和穩(wěn)速段雖都采用PI調(diào)節(jié)器控制，但兩段的PI參數(shù)是不同的，以提高系統(tǒng)的動(dòng)態(tài)響應(yīng)指標(biāo)。在系統(tǒng)的制動(dòng)段，即要對(duì)減速度進(jìn)行必要的控制，以保證舒適感，又要嚴(yán)格地按電梯運(yùn)行的速度和距離的關(guān)系來控制，以保證平層的精度。在系統(tǒng)的轉(zhuǎn)速降至120r/min之前，為了使兩者得到兼顧，采取以加速度對(duì)時(shí)間控制為主，同時(shí)根據(jù)在每一制動(dòng)距離上實(shí)際轉(zhuǎn)速與理論轉(zhuǎn)速的偏差來修正加速度給定曲線的方法。例如在距離平層點(diǎn)的某一距離L處，速度應(yīng)降為Vm/s，而實(shí)際轉(zhuǎn)速高為V′m/s，則說明所加的制動(dòng)轉(zhuǎn)距不夠，因此計(jì)算出此處的給定減速度值-ag后，使其再加上一個(gè)負(fù)偏差ε，即使此處的減速度給定值修正為-（ag+ε）使給定減速度與實(shí)際速度負(fù)偏差加大，從而加大了制動(dòng)轉(zhuǎn)距，使速度很快降到標(biāo)準(zhǔn)值，當(dāng)電動(dòng)機(jī)的轉(zhuǎn)速降到120r/min以后，此時(shí)轎廂距平層只有十幾厘米，電梯的運(yùn)行速度很低，為防止未到平層區(qū)就停車的現(xiàn)象出現(xiàn)，以使電梯能較快地進(jìn)入平層區(qū)，在此段采用比例調(diào)節(jié)，并采用時(shí)間優(yōu)化控制，以保證電梯準(zhǔn)確及時(shí)地進(jìn)入平層區(qū)，以達(dá)到準(zhǔn)確可靠平層。
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