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YBJ200 立式 压饼机 设计 11 CAD

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YBJ200-5多位立式压饼机的设计含11张CAD图,YBJ200,立式,压饼机,设计,11,CAD

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外文翻译Programmable Logic Controllers A programmable logic controller (PLC) is a solid-state device used to control machine motion or process operation by means of a stored program. The PLC sends output control signals output and receive input signals through input/output (I/O) devices. A PLC controls output in response to stimuli at the inputs according to the logic prescribed by the stored program. The inputs are made up of limit switches, pushbuttons, thumbwheels, switches, pulses, analog signal, ASCII serial data, and binary or BCD data from absolute position encoders. The output are voltage or current level to drive end devices such as solenoids, motor starters, relays, lights, and so on. Other output device include analog devices, digital BCD displays, ASCII compatible devices, servo variable-speed drives, and even computers. Programmable controllers were developed (circa in 1968) when General Motors Corps, and other automobile manufacturers were experimenting to see if there might be an alternative to scrapping all their hardwired control panel of machine tools and other production equipment during a model changeover. This annual tradition was necessary because rewriting of the panels was more expensive than buying new ones. The automotive companies approached a number of control equipment manufacturers and asked them to develop a control system that would have a longer productive life without major rewriting, but would still be understandable to and repairable by the plant personnel. The new product was named a “programmable controller”. The processor part of the PLC contains a central processing unit and memory. The central processing unit (CPU) is the “traffic direction” of the processor, the memory stores information. Coming into the processor are the electrical signals from the input devices, as conditioned by the input module to voltage levels acceptable to processor logic. The processor scans the state of I/O and updates outputs stored in the memory of the PLC. For example, the processor may be programmed so that if an input connected to a limit switch is true (limit switch closed), then a corresponding output wired to an output module is to be energized. This processor remembers this command through its memory and compares on each scan to see if that limit switch is, in fact, closed. If it is closed ,the processor energizes the solenoid by turning on the output module. The output device, such as a solenoid or motor starter, is wired to an output modules terminal, and it receives its shift signal from the processor, in effect, the processor is performing a long and complicated series of logic decisions. The PLC performs such decisions sequentially and in according with the stored program. Similarly, analog I/O allows the processor to make decisions based on the magnitude of a signal, rather than just if it is on or off. For example, the processor may be programmed to increase or decrease the steam flow to a boiler (analog output) based on a comparison of the actual temperature in the boiler (analog input ) This is often performed by utilizing the built-in PID (proportional, integral, derivative) capabilities of the processor. Because a PLC is “software based”, its control logic functions can be changed by reprogramming its memory. Keyboard programming devices facilitate entry of the revised program, which can be design to cause an existing machine or process to operate in a different sequence or to different level of, or combinations of stimuli. Hardware modifications are needed only if additional, changed, or relocated input/output device are involved. 中文译文2 可编程序逻辑控制器可编程逻辑控制器（PLC）是一种固态电子装置，它利用已存入的程序来控制机器的运动或工艺的工序。PLC通过输入/输出（I/O）装置信号发出控制信号和接受输入信号。PLC依据以存入程序所规定的逻辑控制输出装置响应的激励。输入装置由限位开关、按钮、手轮、开关、脉冲、模拟信号、ASCII系列数据和来自于绝对位置解码的二进制或BCD数据组成。输出的是驱动电磁线圈、电动起动机、继电器、指示灯等设备的电压或电流电平。其他输出装置包括模拟装置、数字BCD显示、ASCII兼容装置、伺服变速驱动器、甚至计算机。 当通用汽车公司和其他制造商们正在试验看能否有另一种方法来销毁型号转变过程中机床的所有布线控制面板和其他生产设备时，PLC被研制成了（大约在1968年）。这种年度厉行工作是必要的，因为控制面板的重新布线比购买新的控制面板要贵得多。 汽车公司与许多控制设备制造商打交道，请他们开发一个控制系统，这个系统要有较长的生产寿命而无须主要线路重新布线，并且能被工厂人员所理解和维护。这个新系统被称作“可编程控制器”。PLC的处理器部分由中央处理器和存储器组成。中央处理器(CPU)是处理器的“交通控制器”，存储器储存信息。从输入装置来的信号进入处理器后，经输入模块整理成处理器逻辑单元可接受的电压电平。处理器监测I/O的状态，然后依据储存在PLC存储器中指令更新输出。例如，处理器可被编程以便当连接限位开关的输入位真时（限位开关闭合），连在输出上的输出装置被连通，例如，这个输出装置可以是电磁线圈。处理器通过存储器记录下这个指令并与每次检测相比较以确定限位开关是否真正闭合。如果闭合，处理器通过接通输出模块接通电磁线圈。诸如电磁线圈或电动机之类的输出装置被连接到输出模块的接线柱上，并从处理器接受它的位移信号。实际上，处理器在完成一系列长而复杂的逻辑判断。PLC按顺序并根据存储的程序来执行这样的判断。同样地，模拟 I/O装置允许处理器依据