PLC控制全自动洗衣机

PLC控制全自动洗衣机 PLC技术的应用及发展方向 可编程控制器简称——PLC是以微处理器为基础，综合了计算机技术、自动控制技术和通讯技术发展而来的一种新型工业控制装置。它具有结构简单、编程方便、可靠性高等优点，已广泛用于工业过程和位置的自动控制中。据统计，可编程控制器是工业自动化装置中应用最多的一种设备。专家认为，可编程控制器将成为今后工业控制的主要手段和重要的基础设备之一，PLC、机器人、CAD/CAM将成为工业生产的三大支柱。 PLC是在继电器控制逻辑基础上，与3C(Computer,Control,Communication)技术相结合，不断发展完善的。目前已从小规模单机顺序控制，发展到包括过程控制、位置控制等场合的所有控制领域。 自动化系统中所使用的各种类型PLC，有的是集中安装在控制室，有的是分散安装在生产现场的各单机设备上，虽然它们大多处在强电电路和强电设备所形成的恶劣电磁环境中，但PLC是专门为工业生产环境而的控制装置，在设计和制造过程中采用了多层次抗干扰和精选元件措施，故具有较强的适应恶劣工业环境的能力、运行稳定性和较高的可靠性，因此一般不需要采取什么特殊措施就可以直接在工业环境使用。 高可靠性是电气控制设备的关键性能。PLC由于采用现代大规模集成电路技术，采用严格的生产工艺制造，内部电路采取了先进的抗干扰技术，具有很高的可靠性。例如三菱公司生产的F系列PLC平均无故障时间高达30万小时。一些使用冗余CPU的PLC的平均无故障工作时间则更长。从PLC的机外电路来说，使用PLC构成控制系统，和同等规模的继电接触器系统相比，电气接线及开关接点已减少到数百甚至数千分之一，故障也就大大降低。此外，PLC带有硬件故障自我检测功能，出现故障时可及时发出警报信息。在应用软件中，应用者还可以编入外围器件的故障自诊断程序，使系统中除PLC以外的电路及设备也获得故障自诊断保护。这样，整个系统具有极高的可靠性也就不奇怪了。 长期以来，plc始终处于工业控制自动化领域的主战场，为各种各样的自动化控制设备提供非常可靠的控制，与dcs和工业pc形成了三足鼎立之势。同时，plc也承受着来自其它技术产品的冲击，尤其是工业pc所带来的冲击。 目前，全世界plc生产厂家约200家，生产300多种产品。国内plc市场仍以国外产品为主，如siemens、modicon、a-b、omron、三菱、ge的产品。经过多年的发展，国内plc生产厂家约有三十家，但都没有形成颇具规模的生产能力和名牌产品，可以说plc在我国尚未形成制造产业化。在plc应用方面，我国是很活跃的，应用的行业也很广。专家估计，2000年plc的国内市场销量为15(20万套(其中进口占90%左右)，约25(35亿元人民币，年增长率约为12%。预计到2005年全国plc需求量将达到25万套左右，约35(45亿元人民币。 plc市场也反映了全世界制造业的状况，2000后大幅度下滑。但是，按照automation research corp的预测，尽管全球经济下滑，plc市场将会复苏，估计全球plc市场在2000年为76亿美元，到2005年底将回到76亿美元，并继续略微增长。 微型化、网络化、pc化和开放性是plc未来发展的主要方向。在基于plc自动化的早期，plc体积大而且价格昂贵。但在最近几年，微型plc(小于32 i/o)已经 出现，价格只有几百欧元。随着软plc(soft plc)控制组态软件的进一步完善和发展，安装有软plc组态软件和pc-based控制的市场份额将逐步得到增长。 当前，过程控制领域最大的发展趋势之一就是ethernet技术的扩展，plc也不例外。现在越来越多的plc供应商开始提供ethernet接口。可以相信，plc将继续向开放式控制系统方向转移，尤其是基于工业pc的控制系统。 目前，PLC在国内外已广泛应用于钢铁、石油、化工、电力、建材、机械制造、汽车、轻纺、交通运输、环保及文化娱乐等各个行业，使用情况大致可归纳为如下几类: 开关量的逻辑控制:这是PLC最基本、最广泛的应用领域，它取代传统的继电器电路，实现逻辑控制、顺序控制，既可用于单台设备的控制，也可用于多机群控及自动化流水线。如注塑机、印刷机、订书机械、组合机床、磨床、包装生产线、电镀流水线等;模拟量控制:在工业生产过程当中，有许多连续变化的量，如温度、压力、流量、液位和速度等都是模拟量。为了使可编程控制器处理模拟量，必须实现模拟量(Analog)和数字量(Digital)之间的A/D转换及D/A转换。PLC厂家都生产配套的A/D和D/A转换模块，使可编程控制器用于模拟量控制;运动控制:PLC可以用于圆周运动或直线运动的控制。从控制机构配置来说，早期直接用于开关量I/O模块连接位置传感器和执行机构，现在一般使用专用的运动控制模块。如可驱动步进电机或伺服电机的单轴或多轴位置控制模块。世界上各主要PLC厂家的产品几乎都有运动控制功能，广泛用于各种机械、机床、机器人、电梯等场合;过程控制:过程控制是指对温度、压力、流量等模拟量的闭环控制。作为工业控制计算机，PLC能编制各种各样的控制算法程序，完成闭环控制。PID调节是一般闭环控制系统中用得较多的调节方法。大中型PLC都有PID模块，目前许多小型PLC也具有此功能模块。PID处理一般是运行专用的PID子程序。过程控制在冶金、化工、热处理、锅炉控制等场合有非常广泛的应用;数据处理:现代PLC具有数学运算(含矩阵运算、函数运算、逻辑运算)、数据传送、数据转换、排序、查、位操作等功能，可以完成数据的采集、分析及处理。这些数据可以与存储在存储器中的参考值比较，完成一定的控制操作，也可以利用通信功能传送到别的智能装置，或将它们打印制表。数据处理一般用于大型控制系统，如无人控制的柔性制造系统;也可用于过程控制系统，如造纸、冶金、食品工业中的一些大型控制系统;通信及联网:PLC通信含PLC间的通信及PLC与其它智能设备间的通信。随着计算机控制的发展，工厂自动化网络发展得很快，各PLC厂商都十分重视PLC的通信功能，纷纷推出各自的网络系统。新近生产的PLC都具有通信接口，通信非常方便。 PLC technology and development Short PLC - PLC is a microprocessor-based, integrated computer technology, automatic control technology and communication technologies developed from a new type of industrial control devices. It has a simple structure, easy programming, high reliability, has been widely used for industrial process and location of the automatic control. According to statistics, the programmable controller is the most widely used industrial automation equipment in a device. Experts believe that the PLC will become the main means of industrial controls and one of important infrastructure, PLC, robotics, CAD / CAM will be the three pillars of industrial production. PLC is based on the relay control logic, and the 3C (Computer, Control, Communication) technology, continuous development of sound. Now the order of small-scale stand-alone control, the development to include process control, position control and other occasions, all the control areas. Automation systems of various types used in the PLC, some focused installed in the control room, some scattered in the production site to install the stand-alone device, although most of them are in strong electrical circuit and the formation of strong electric equipment in the harsh electromagnetic environment, But the PLC is specifically designed for the industrial production environment control device, in the design and manufacturing process using multi-level anti-jamming measures and selected components, it has a strong ability to adapt to harsh industrial environments, operating stability and high reliability, it is generally not need to take any special measures to be used directly in the industrial environment. High reliability is the key to the performance of electrical control equipment. PLC as the use of modern large scale integrated circuit technology, strict production process, the internal circuit to take the advanced anti-jamming technology, with high reliability. For example, the production of F series Mitsubishi PLC MTBF of up to 30 million hours. Some of the PLC CPU using the redundant average time between failures is longer. The external circuit from the PLC of the machine, the use of PLC control system constituted, and the same scale relay contactor systems, electrical wiring and switch contacts has been reduced to hundreds or even thousands of times, the failure will be greatly reduced. In addition, PLC hardware failure with self-detection, failure to give timely warning information. In the application software, application are also incorporated into the peripheral device fault diagnosis procedure, the system in addition to PLC circuits and devices other than the failure to obtain protection from the diagnosis. In this way, the entire system with extremely high reliability is not surprising. For a long time, plc is always in the field of industrial automation control the main battlefield for a variety of automation and control equipment provides a very reliable control programs, industrial pc with the dcs and the formation of a three pillars. At the same time, plc also suffer from the impact of other technology products, in particular the impact of industrial pc. Currently, the world plc about 200 manufacturers, producing 300 kinds of products. Plc domestic market is still foreign products, such as siemens, modicon, ab, omron, Mitsubishi, ge products. After years of development, the domestic manufacturers are about thirty plc, but did not form a large-scale production capacity and brand-name products, it can be said plc has not yet formed in the manufacturing industry in China. Plc applications in China is very active, the application of the industry is very broad. Experts estimate that the domestic market in 2000 sold plc 15 (20 million units (of which imports accounted for about 90%), 25 (35 billion yuan, the annual growth rate of about 12%. Is expected to demand the 2005 National plc reached 25 million units, about 35 (45 billion yuan. plc the world market also reflects the status of the manufacturing sector, a significant decline after 2000. However, in accordance with the automation research corp forecasts, despite the global economic downturn, plc market will recover, estimated global plc market in 2000 was 76 billion U.S. dollars, to the end of 2005 will return 7.6 billion, and continue to grow slightly. Miniaturization, networking, pc based plc and openness is the main direction of future development. Early plc based automation, plc bulky and expensive. But in recent years, micro plc (less than 32 i / o) have emerged, the price only a few hundred euros. With the soft plc (soft plc) control configuration software to further improve and develop, install the configuration software soft plc and pc-based control of the market share will gradually increase. Currently, the field of process control is one of the biggest trends in the expansion of ethernet technology, plc is no exception. More and more vendors began offering plc ethernet interface. It is believed that, plc will continue to shift the direction of open control systems, particularly industrial pc based control system. Currently, PLC at home and abroad has been widely used in steel, petroleum, chemical, electric power, building materials, machinery manufacturing, automobile, textile, transportation, environmental protection and cultural entertainment and other industries, the use can be summarized into the following categories: The logic control switch: This is the PLC the most basic and wide range of applications, which replaces the traditional relay circuit, logic control, sequential control, both for the control of a single piece of equipment can also be used for multi-group control and automation lines. Such as injection molding machines, printing presses, staples machinery, machine tool, grinding, packaging production lines, plating lines, etc.; analog volume control: in the industrial production process, there are many continuous changes in volume, such as temperature, pressure, flow, level and speed, are all analog. In order to deal with analog programmable controller, you must realize analog (Analog) and digital (Digital) between the A / D conversion and D / A conversion. PLC manufacturers are supporting the production of A / D and D / A converter module, the programmable controller used for analog control; Motion Control: PLC can be used in a circular motion or linear motion control. Configuration from the control mechanism, the early switch directly to I / O module connection position sensors and actuators, is now generally use a dedicated motion control module. For example a stepper motor or servo motor driven single-axis or multi-axis position control module. The world's major PLC manufacturers of the products almost every motion control functions, widely used in various machinery, machine tools, robots, elevators and so on; Process Control: Process control refers to the temperature, pressure, flow and other analog closed-loop control . As an industrial control computer, PLC control algorithm can prepare a variety of procedures to complete the closed-loop control. PID closed loop control system adjustment is generally a lot about the adjustment method used. PLC has a PID and medium-sized module, now many small PLC also has this feature module. PID deal with the general PID is running special subroutines. Process control in metallurgy, chemical industry, heat treatment, boiler control and so on have a very wide range of applications; data processing: the modern PLC has a mathematical operation (including matrix operations, functions, operations, logic operations), data transfer, data conversion, sorting, look-up table, bit operation functions, you can complete the data collection, analysis and processing. These data can be stored in the memory comparison reference value, to complete a certain degree of control operations can also be used to send communication to other intelligent devices, or print them watch. Generally used for large-scale data processing control system, if no control of flexible manufacturing systems; also be used for process control systems, such as paper making, metallurgy, food industry in some large-scale control system; communications and networking: PLC communication between the PLC with PLC and other communication and communication between intelligent devices. With the development of computer control, factory automation network have developed rapidly, the PLC manufacturers have attached great importance to PLC communications capabilities, have launched their own network. Have recently produced PLC communication interface, communication is very convenient