Teaching Reform and Exploration of Practical Courses Based on Programmable Control

As the country continues to promote the development of intelligent manufacturing,all industries are carrying out enterprise automation upgrading,the Pearl River Delta Intelligent Manufacturing Conference held in March 2024 provides a direction guide for each enterprise on how to integrate the intelligent manufacturing technology into each link and provide direction guidance for enterprises to create new models and new business formats.College teachers,in focusing on the teaching process,should closely match the enterprise and social needs and cultivate excellent students.As the core controller of automation control,the application of programmable controllers in teaching is particularly important.In practical classes,by setting progressive difficulty,project guidance,team collaboration,and other links,students can master the automation equipment design of programmable control in repeated practice.

Programmable Logic Controller Block Monitoring System for Memory Attack Defense in Industrial Control Systems

Cyberattacks targeting industrial control systems(ICS)are becoming more sophisticated and advanced than in the past.A programmable logic controller(PLC),a core component of ICS,controls and monitors sensors and actuators in the field.However,PLC has memory attack threats such as program injection and manipulation,which has long been a major target for attackers,and it is important to detect these attacks for ICS security.To detect PLC memory attacks,a security system is required to acquire and monitor PLC memory directly.In addition,the performance impact of the security system on the PLC makes it difficult to apply to the ICS.To address these challenges,this paper proposes a system to detect PLC memory attacks by continuously acquiring and monitoring PLC memory.The proposed system detects PLC memory attacks by acquiring the program blocks and block information directly from the same layer as the PLC and then comparing them in bytes with previous data.Experiments with Siemens S7-300 and S7-400 PLC were conducted to evaluate the PLC memory detection performance and performance impact on PLC.The experimental results demonstrate that the proposed system detects all malicious organization block(OB)injection and data block(DB)manipulation,and the increment of PLC cycle time,the impact on PLC performance,was less than 1 ms.The proposed system detects PLC memory attacks with a simpler detection method than earlier studies.Furthermore,the proposed system can be applied to ICS with a small performance impact on PLC.

Mine-Hoist Active Fault Tolerant Control System and Strategy

Based on fault diagnosis and fault tolerant technologies, the mine-hoist active fault-tolerant control system (MAFCS) is presented with corresponding strategies,, which includes the fault diagnosis module (FDM), the dynamic library (DL) and the fault-tolerant control module (FCM). When a fault is judged from some sensor by FDM, FCM reconfigure the state of MAFCS by calling the parameters from all sub libraries in DL, in order to ensure the reliabil- ity and safety of mine hoist. The simulating result shows that, MAFCS is of certain intelligence, which can adopt the corresponding control strategies according to different fault modes, even when there are quite difference between the real data and the prior fault modes.

Application of Programmable Controller in a Rail Welding Machine

An innovation is conducted on a K190πK rail auto welding machine because of its poor stability in quality of welding joints. A new control system based on a programmable controller is designed to replace the old one. The new control system is of higher accuracy in controlling sequence and good ability in anti disturbance, and is convenient to operate. The comparison tests are carried out. The experimental results show that the quality of welded joints is greatly increased by the improved welding mechine.

Application of PLC programmable control technology in the mine pit transportation system

This paper summarizes the definition, function, and characteristics of the programmable conlrol technology, and especially analyzes the operation mode of the 750V DC traction power supply system, the protection setting the defects of the original system and the factors influencing the safety of power supply. Aimed at the equipment of the PLC programmable control system used in the mine transportation system in recent years, combining parts of the PLC programmable control system equipment used and installed in Tong Ting Coal Mine, this paper introduces the role of the PLC programmable control system and the economic benefits and safety effect.

Design of 32 kbit one-time programmable memory for microcontroller units

A 32 kbit OTP(one-time programmable)memory for MCUs(micro-controller units)used in remote controllers was designed.This OTP memory is used for program and data storage.It is required to apply 5.5V to BL(bit-line)and 11V to WL(word-line)for a OTP cell of 0.35μm ETOX(EEPROM tunnel oxide)type by MagnaChip.We use 5V transistors on column data paths to reduce the area of column data paths since they require small areas.In addition,we secure device reliability by using HV(high-voltage)transistors in the WL driver.Furthermore,we change from a static logic to a dynamic logic used for the WL driver in the core circuit.Also,we optimize the WD(write data)switch circuit.Thus,we can implement them with a small-area design.In addition,we implement the address predecoder with a small-area logic circuit.The area of the designed 32 kbit OTP with 5V and HV devices is 674.725μm×258.75μm(=0.1745mm2)and is 56.3% smaller than that using 3.3V devices.

A novel fuzzy logic direct torque controller for a permanent magnet synchronous motor with a field programmable gate array

A high-performance digital servo system built on the platform of a field programmable gate array (FPGA),a fully digitized hardware design scheme of a direct torque control (DTC) and a low speed permanent magnet synchronous motor (PMSM) is proposed. The DTC strategy of PMSM is described with Verilog hardware description language and is employed on-chip FPGA in accordance with the electronic design automation design methodology. Due to large torque ripples in low speed PMSM,the hysteresis controller in a conventional PMSM DTC was replaced by a fuzzy controller. This FPGA scheme integrates the direct torque controller strategy,the time speed measurement algorithm,the fuzzy regulating technique and the space vector pulse width modulation principle. Experimental results indicate the fuzzy controller can provide a controllable speed at 20 r min-1 and torque at 330 N m with satisfactory dynamic and static performance. Furthermore,the results show that this new control strategy decreases the torque ripple drastically and enhances control performance.

基于5G多接入边缘计算的云化PLC系统架构设计与应用

随着工业控制系统对柔性化、扁平化的要求不断提升,以PLC为构建基础的传统工业控制网络在大规模接入、算力提升和部署灵活性方面均受到限制.针对这些问题,融合5G网络和边缘计算技术,设计了基于5G多接入边缘计算的云化PLC系统架构,阐述了该架构的运行机制和所涉及的关键技术;在此基础上,进行PLC系统的云化部署和调试,实现了工业现场、企业数据中心、5G网络和边缘网络的集成;最后,通过在某汽车制造公司产线改造过程中的应用,验证了所提架构的有效性.

基于PLC技术的联合收割机电气控制系统设计

以联合收割机电气控制系统为研究对象,利用可编程控制器(PLC)对联合收割机电气控制系统进行改进,以提高联合收割机运行效率和可靠性。通过对联合收割机的工作原理和液压作动系统进行分析,基于可编程控制器(PLC)进行联合收割机电气系统整体设计,并对电气系统的运行效果进行测试分析。试验结果表明:系统运行可靠,能够获得良好的收割效果,可将收割损失率控制在2%以内,验证了系统运行过程稳定性。

基于PLC反渗透海水淡化控制系统的设计与开发

针对反渗透海水淡化系统工艺复杂、运维繁琐、对操作人员专业技能要求高的特点,研发了一套反渗透海水淡化控制系统。详细研究整个工艺系统中预处理、反渗透等关键工艺环节的原理及自动控制过程。从系统的硬件设计和软件开发两个方面进行详细阐述。硬件设计方面,根据装置规模和控制需求完成控制系统设备选型。软件开发方面,完成控制器及人机交互界面多套软件的开发。该系统成功应用于高校反渗透海水淡化教学实践课。应用结果表明:该系统设计合理、操作界面简洁方便,在稳定安全运行的同时可实现教学培训、故障处理等目的。该系统在提高海水淡化操作人员专业技能的同时,也对高校创新其他专业的实操培训课程提供了借鉴和技术支撑。

面向学科交叉融合的综合性实训教学装置设计与教学实践

针对工程训练实训教学装置功能单一、缺乏多学科交叉与整合能力等问题,以多种特征的物料识别与分拣为应用背景,在综合应用PLC控制技术、传感器技术、气动控制与机电传动控制技术的基础上,结合数字图像处理与卷积神经网络技术,基于树莓派与Jetson嵌入式计算平台,自主研制了一种物料特征识别与分拣综合实训教学装置。与现有同类实训装置相比,该自制实训装置具有体积小,功能多和成本低的优势。实践教学表明,将传统PLC控制与人工智能技术元素有机结合,以及将课内教学延伸至创客活动和学生第二课堂,能有效提升学生的工程认知水平和工程实践能力,体现多学科交叉、多技术融合的高等工程教育特征。

基于DCS控制技术的造纸定量监测系统设计和实现

为实现对制浆造纸定量环节的自动化监测,提高造纸企业的自动化管理水平,基于抄纸工艺的一般流程和PID控制技术制订了一项水分定量解耦控制策略,并通过对角阵解耦法明确纸张定量控制策略的基本思路。在此基础上,基于纸机车速、上浆流量和上浆浓度3项指标来实现对纸张生产的定量管理,通过带有初始化功能的PSO算法对PID控制器进行参数整定。为实现上述算法的实地应用,基于SIMATIC S7-200 SMART可编程控制器建立了一套造纸定量监测DCS控制系统,并通过WinCC项目中的OPC驱动程序输入PID参数,最后运用Simulink完成数据交换。为验证该系统的有效性,在某造纸企业的造纸定量工序中随机提取了250个扫描点并输出相应的定量偏差曲线。经实际测量发现,该系统控制下的纸张定量波动处于±1g/m2的可接受范围内,实现了较为精准的定量检测。

脉冲式连续微波干燥树莓果浆的控制系统和品质优化

为改善微波加热均匀性,提高连续式微波干燥树莓果浆干后品质,在自行研制脉冲式微波输出可编程控制器(Programmable Logic Controller,PLC)控制系统上,采用中心组合试验设计方法,分析微波占空比、脉冲周期、风速和干燥时间四个实验因素对树莓果浆的平均温度、温度离散值、含水率、水分含量离散值、花青素保留率和花青素保留率离散值指标的影响规律,获得脉冲式微波干燥树莓果浆的最佳工艺。对比脉冲式微波干燥与常用的反馈控温微波干燥、间歇微波干燥和连续式微波干燥工艺的果浆干后品质及均匀性指标,进而研制连续式微波干燥树莓果浆品质优化控制系统。结果表明,脉冲式微波干燥通过PLC控制系统,使磁控管以脉冲形式输出矩形波形式功率,间歇性地开启磁控管比连续微波加热更有效,并且采用脉冲式微波干燥树莓果浆具有更优产品品质和加热效率,对比反馈控温系统成本更低可靠性更好。脉冲式微波干燥树莓果浆的最佳工艺为:微波占空比0.6、脉冲周期17 s、风速1.9 m/s、干燥时间12.5 min。相比于连续式微波干燥,脉冲式微波干燥果浆品质最优,脉冲式干后果浆花青素保留率提高35.31%±0.55%,反馈控温下提高33.59%±0.23%,间歇微波下提高16.42%±0.18%。脉冲式微波干燥通过控制功率降低果浆干后温度,改善干后品质均匀性,为树莓干制品工业化生产提供依据。

造纸机分布传动可编程控制器PCC系统的应用

PCC可编程控制器以其强大的数据处理能力、高运算速度和可靠网络连接等优势,在在造纸工业中得到广泛应用,充分发挥其优势有助于推进造纸机的智能化发展、提升造纸机的技术水平。对此,简述了PCC系统控制原理,设计了以PCC B&R 2005为主控制器、操作面板为人机界面、PROFIBUS现场总线为通信方式的造纸机分布传动控制系统,对系统中主要硬件选型与配置、系统通信方式、下位机软件设计等进行了详细说明,并基于组态王与PCC进行造纸机分布传动上位机监控界面的设计,以期提高造纸机分布传动控制系统的控制精度、实时性和稳定性。

自主可控可编程控制系统架构及关键技术分析

主要对自主可控可编程控制系统架构以及关键技术进行分析。首先,对可编程控制系统架构特点进行分析,包括:选用实时以太网总线具有高同步性特点,同时应用具有标准化特色的应用层协议;主站从站通用化水平持续提升;功能呈现出丰富化发展趋势。其次,对自主可控可编程控制系统关键技术及其实现进行分析,包括主站从站硬件标准化、实时以太网总线控制器、HMI组态编程、PLCopen功能库这4个方面的内容。希望能够通过自主可控可编程控制系统关键技术的综合应用,促进可编程控制系统优化发展,进而在工业控制产品自主化建设发展方面起到积极作用与价值。

基于PLC的气动搬运机械手自动控制系统设计

为提高气动搬运机械手在复杂工厂流水线中的运行效率,该文设计了一套基于PLC的气动搬运机械手自动控制系统。在分析通用气动机械手将物品在不同位点之间搬运的运动流程的基础上,设计了自动控制系统的硬件架构。其中包含了可编程逻辑控制器(PLC)、伺服电机、传感器和交互屏等器件,并根据气动搬运机械手的运动流程,设计了相应的软件控制程序及界面。仿真实验结果证明,所提出的气动搬运机械手自动控制系统可以稳定地完成实验预设的功能需求,自动化程度较高。

PLC在螺杆式启闭机预防螺杆压弯保护中的应用

螺杆式启闭机在日常使用下降过程中螺杆被压弯的现象时有发生,其主要原因是水闸门槽或闸室底板有较大坚硬异物一般不易被运行管理人员察觉,若异物没有被及时清理,会导致闸门运行缓慢甚至停滞。现有的保护系统很难做到及时、精准的动作,可能会造成螺杆被不同程度地压弯。通过直接跟踪闸门实时位移速度这一途径,利用PLC快速精准测量速度,并在螺杆启闭机发生异常时及时断电停机,可有效避免上述现象的发生。

PLC技术在电气设备自动化控制中的应用

阐述PLC技术在电气设备自动化控制中的应用特点,包括可编程、灵活性、可靠性、实时性和可视化界面。探讨PLC技术在开关量控制、闭环控制、顺序控制中的控制应用。

基于可编程序控制器和变频器的多段速控制系统

基于可编程序控制器和变频器设计了一套多段速控制系统。在分析多段速控制系统控制要求的基础上,进行可编程序控制器与变频器的硬件接线,分配可编程序控制器的输入输出地址,配置变频器的参数。设计多段速控制系统的时序图和顺序功能图,采用定时器指令为主体编写梯形图。通过调试确认,所设计的多段速控制系统能够满足控制要求,运行稳定可靠。