PLC控制的变频电梯系统的设计.docx
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1、 毕业设计说明书(论文)毕业实践任务书课题名称 PLC控制的变频电梯系统的设计 指导教师 职 称 专业名称 班 级 学 生 姓 名 学 号 课题需要完成的任务:电梯控制的基本思路是当电梯上升下降时,在上升下降的同时,要顾和到等待时间、加速时间,人性化的设计。在上升时,有人按了上升按钮,则要在经过的时候停止,开门;下降时亦相同。系统主要通过变频器,PLC,曳引电机,按钮四部分构成。按钮相连PLC的I/O口,按下按钮的时候,PLC将信号转换为了模拟信号,传给变频器,变频器改变曳引电机的转向。其中曳引电机的速度改变。主要完成任务如下:(1) 三菱公司的FX2N-80MR-D模拟量扩展模块的程序设计(
2、2) 变频器控制的程序设计课题计划:x.xx.x 熟悉课题,准备资料; x.xx.x 设计硬件; x.xx.x 编写毕业设计论文; x.xx.x 准备毕业答辩。计划答辩时间:xxxx年x月x日x日 xxxxxx(分院、系部)xxxx年xx 月xx日外文翻译INDUSTRIAL AND COLLABORATIVE CONTROL SYSTEMS- A COMPLEMENTARY SYMBIOSIS Looking at todays control system one can find a wide variety of implementations. From pure industria
3、l to collaborative control system (CCS) tool kits to home grown systems and any variation in-between. Decisions on the type of implementation should be driven by technical arguments Reality shows that financial and sociological reasons form the complete picture. Any decision has its advantages and i
4、ts drawbacks. Reliability, good documentation and support are arguments for industrial controls. Financial arguments drive decisions towards collaborative tools. Keeping the hands on the source code and being able to solve problems on your own and faster than industry are the argument for home grown
5、 solutions or open source solutions. The experience of many years of operations shows that which solution is the primary one does not matter, there are always areas where at least part of the other implementations exist. As a result heterogeneous systems have to be maintained. The support for differ
6、ent protocols is essential. This paper describes our experience with industrial control systems, PLC controlled turn key systems, the CCS tool kit EPICS and the operability between all of them.FUNCTIONALITY The ever lasting question why control systems for accelerators and other highly specialized e
7、quipment are often home grown or at least developed in a collaboration but only in rare cases commercial shall not be answered here. We try to summarize here basic functionalities of different controls approaches.Front-end Controller One of the core elements of a control system is the front-end cont
8、roller. PLCs can be used to implement most of the functions to control the equipment. The disadvantage is the complicated access to the controls properties. For instance all of the properties of a control loop like the P, I and D parameter, but also the alarm limits and other additional properties m
9、ust be addressed individually in order to identify them in the communication protocol and last not least in the display-, alarm- and archive programs. In addition any kind of modifications of these embedded properties is difficult to track because two or more systems are involved. This might be one
10、strong argument why control loops are mainly implemented on the IOC level rather than PLCs. I/O and Control Loops Complex control algorithms and control loops are the domain of DCS alike control systems. The support for sets of predefined display and controls properties is essential. If not already
11、available (like in DCS systems) such sets of generic properties are typically specified throughout a complete control system (see namespaces). Sequence/ State programs Sequence programs can run on any processor in a control system. The runtime environment depends on the relevance of the code for the
12、 control system. Programs fulfilling watchdog functions have to run on the front-end processor directly. Sequence programs for complicated startup and shutdown procedures could be run on a workstation as well. The basic functionality of a state machine can be even implemented in IEC 61131. Code gene
13、rators can produce C code which can be compiled for the runtime environment. Supported Hardware The support for field buses and Ethernet based I/O is a basic functionality for SCADA type systems it is commercially available from any SCADA system on the market. The integration of specific hardware wi
14、th specific drivers and data conversion is the hard part in a commercial environment. Open APIs or scripting support sometimes help to integrate custom hardware. If these tools are not provided for the control system it is difficult if not impossible - to integrate custom hardware. New industrial st
15、andards like OPC allow the communication with OPC aware devices and the communication between control systems. One boundary condition for this kind of functionality is the underlying operating system. In the case of OPC it is bound to DCOM which is a Microsoft standard. UNIX based control systems ha
16、ve a hard time to get connected. Only control systems supporting multiple platforms can play a major role in a heterogeneous environments. As a result the limited support for custom- or specialized hardware may give reason for the development of a new control system.1.Graphic Synoptic displays are t
17、he advertising sign for any control system. Commercial synoptic displays come with a rich functionality and lots of special features. Starting to make use of all these features one will find out that all individual properties of the graphic objects must be specified individually. Since SCADA systems
18、 must be generic they cannot foresee that an input channel does not only consist of a value but also consists of properties like display ranges and alarm values. Defining all of these properties again and again can be a pretty boring job. Some systems allow to generate prototypes of graphic objects.
19、 These prototype or template graphics are complex and need a specialist to generate them. DCS or custom synoptic display programs can make use of the common set of properties each I/O point provides. This predefined naming scheme will fill in all standard property values and thus only require to ent
20、er the record or device name into the configuration tool. A clear advantage for control systems with a notion of I/O objects rather than I/O points.2.Alarming Alarms are good candidates to distinguish between different control system architectures. Those systems which have I/O object implemented als
21、o provide alarm checking on the front-end computer. Those systems which only know about I/O points have to add alarm checking into the I/O processing. While the I/O object approach allows to implement alarm checking in the native programming language of the front-end system, I/O point oriented syste
22、ms typically have to implement this functionality in their native scripting language. This is typically less efficient and error prone because all properties must be individually configured. This leads to a flood of properties. Not only the error states for each I/O point wind up to be individual I/
23、O points but also the alarm limits and the alarm severity of each limit must be defined as I/O points if it is desired to be able to change their values during runtime. Besides this impact on the configuration side the processing and forwarding of alarms makes the difference between SCADA and DCS sy
24、stems. Since SCADA systems inherently do not know about alarms, each alarm state must be polled either directly from the client application or in advanced cases from an event manager which will forward alarm states to the clients. In any case a lot of overhead for just checking alarm limits. DCS sys
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- PLC 控制 变频 电梯 系统 设计
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