基于PLC模拟量的直流电动机转速控制系统-毕业论文.docx

PAGE I PAGE PAGE 15 PAGE PAGE 16 本科毕业论文（设计） 基于PLC模拟量的直流电动机转速控制系统Speed control system of DC motor based on PLC 基于PLC模拟量的直流电动机转速控制系统 Speed control system of DC motor based on PLC Simulation quantity Phtotelectric sensor and its application Phtotelectric sensor and its application Phtotelectric sensor and its application 摘 要 电机通常用于工业控制、自动化和家用电器。它涵盖了从家用洗衣机、风扇、手持电动工具、汽车车窗提升机、牵引力控制系统、工业驱动等诸多领域。当改变带有负载的电动机的转速时，其仍可以均匀平滑的无极调速并可以在较小与较大的转速范围内自由变换。因此，直流电动机广泛的应用于大型轧钢机、卷扬机、电力机车等需要在很大的负载下起动或均匀调速的机械。没有控制系统，电机应用就不能完成。调速控制系统就是通过对电动机的控制，将电能转化成机械能，并通过控制工作机械按给定的运动规律运行的装置。可编程控制器（PLC）是为了达到工业自动化的目的而设计用计算机来操控的设备。由于PLC可以方便快捷的处理模拟量与数字量之间的转换，可使用范围广，编程简单，使其常被用来作为现场的数据采集与设备控制。本课题主要研究应用S7-200PLC模拟量对直流电机转速进行控制，以PLC作为核心控制器控制模拟量输出，从而控制直流电动机的转速。 关键词：直流电动机；调速系统；PLC  Abstract Motors?are?commonly?used?in?industrial?control,?automation?and?household?appliances.?It?covers?everything?from?home?washing?machines,?fans,?handheld?power?tools,?car?window?hoist,?traction?control?system,?industrial?drive?and?many?other?fields.?When?the?speed?of?the?motor?with?load?is?changed,?it?can?still?be?evenly?smoothed?by?the?infinite?speed?regulation?and?can?be?freely?transformed?in?a?small?and?larger?rotational?speed?range.?Therefore,?DC?motor?is?widely?used?in?large?rolling?mill,?hoists,?electric?locomotives?and?other?machinery?that?need?to?start?under?a?large?load?or?uniform?speed?regulation.?Without?a?control?system,?the?motor?application?cannot?be?completed.?Speed?control?system?is?through?the?control?of?the?motor,?the?electrical?energy?into?mechanical?energy,?and?through?the?control?of?the?working?machinery?according?to?a?given?movement?law?of?the?device.?Programmable?controller?(PLC)?is?a?computer-controlled?device?designed?to?achieve?the?purpose?of?industrial?automation.?Because?PLC?can?easily?and?quickly?deal?with?the?conversion?between?analog?and?digital?quantities,?can?be?used?a?wide?range,?simple?programming,?so?that?it?is?often?used?as?field?data?acquisition?and?equipment?control.?This?paper?ma