• Title, Summary, Keyword: PLC

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Design of a Vehicle Assembly Line Using PLC Simulation (PLC 시뮬레이션을 이용한 자동차 조립 라인 설계)

  • Lee, Chang-Ho;Wang, Gi-Nam;Park, Sang-Chul
    • Korean Journal of Computational Design and Engineering
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    • v.14 no.5
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    • pp.323-329
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    • 2009
  • Auto-makers can only remain competitive by producing high quality vehicles in an efficient way. In designing a production line, one of the most important objectives of digital manufacturing is to verify design errors as early as possible. In terms of the cost and time saving, it is very essential to start the construction of a production line with a proven design which is error-free. Likewise, this paper aims to implement PLC verification using an example. The verification in automobile manufacturing means verifying PLC program, which control automatic devices. In this paper, we built a virtual factory to implement PLC simulation and introduced verification procedure using PLC Studio. Finally, we can prove the availability for the PLC verification.

UML-based PLC Ladder Logic Design and Automatic Generation of Ladder Code (UML 기반 PLC 래더 로직 설계와 코드 자동 생성)

  • Han, Kwan-Hee;Park, Jun-Woo
    • Korean Journal of Computational Design and Engineering
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    • v.14 no.1
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    • pp.50-59
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    • 2009
  • There are two main problems in the current PLC ladder programming practices: First, currently there are no widely adopted systematic design methods to deal with PLC based control systems in the shop floor. So, the control logic design phase is usually omitted in current PLC programming development life cycle. Second, PLC ladder logic provides only microscopic view of system processes. As a result, it is difficult for FA engineers to have overall perspectives about the interaction of system components intuitively during the verification step of logic errors. To solve these problems, this paper proposed object-oriented design and automatic generation method of PLC ladder logic. Based on the proposed method, the computer software to assist the automatic ladder logic generation is also developed.

A Study on the Control of Solenoid Valve for Heating by using Power Line Communication (PLC) (전력선 통신을 이용한 난방용 솔레노이드밸브 제어에 관한 연구)

  • 신관우;김용태;이윤섭
    • Journal of Institute of Control, Robotics and Systems
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    • v.9 no.8
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    • pp.647-650
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    • 2003
  • PLC (Power Line Communication) is the communication method using the existing power line installed in houses and offices to convert and transmit high frequency communication signal from tens of KHz to tens of MHz, and receive the filtered signal using high frequency filter The advantage of PLC is that PLC uses the existing power line installed in houses and offices so it does not require separate power line. Easy and convenient access using electric outlets is another advantage of PLC. However, PLC has some disadvantages such as limited transmission power, high load interference and noise, variable signal attenuation, characteristic of impedance, and selective possibility of frequency property. We designed the boiler temperature control system unit by using the PLC modem. We can avoid unnecessary heating of separate temperature control unit, and save the cost accordingly control stability of the proposed system is proven through the experiment.

A Study on an Integer Frequency Offset Estimation and Compensation for DOCSIS 3.1 Downstream

  • Bae, JaeHwui;Song, JinHyuk;Ra, Sang-Jung;Choi, Dong-Joon;Jung, Joon-Young;Hur, Namho
    • IEIE Transactions on Smart Processing and Computing
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    • v.6 no.1
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    • pp.39-46
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    • 2017
  • In this paper, we propose an integer frequency offset estimation and compensation method based on PLC preamble correlation in DOCSIS 3.1 Downstream system. The proposed method determines the PLC preamble subcarrier location recovered from PLC data and the one obtained from PLC preamble correlation. We showed the performance of PLC preamble detection in the received signal through the maximum value detection of PLC preamble correlation. Thus we can estimate and compensate for the integer frequency offset by computing the difference of PLC subcarrier locations.

Design and Implementation of Web-based PLC Laboratory for Industrial Automation Training (산업 자동화 교육훈련을 위한 웹기반 PLC 실험실의 설계 및 구현)

  • Han, Earl;Park, Sung-Moo;Hong, Sang-Eun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.1
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    • pp.101-106
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    • 2010
  • Due to significant advances in Internet technology, there have been many e-learning courses offered by universities and academic institutes nowadays through the Internet. And these courses have benefited many students who might be constrained by distance and time. Nevertheless, most web-based courses are lecturing courses that cannot fulfill the needs for engineering technology education. In this paper, we propose the design and implementation of web-based programmable logic controller(PLC) laboratory to support learning and training for industrial automation. The proposed web-based PLC laboratory system consists of virtual labs and remote labs. This web-based PLC laboratory can be accessed by registered students to practice PLC experiments at their own home, enhancing the quality of education without much increasing in the overall cost. With the help of web cameras, the students can even have experience the live PLC experiments through the Internet.

Executable Code Sanitizer to Strengthen Security of uC/OS Operating System for PLC (PLC용 uC/OS 운영체제의 보안성 강화를 위한 실행코드 새니타이저)

  • Choi, Gwang-jun;You, Geun-ha;Cho, Seong-je
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.29 no.2
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    • pp.365-375
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    • 2019
  • A PLC (Programmable Logic Controller) is a highly-reliable industrial digital computer which supports real-time embedded control applications for safety-critical control systems. Real-time operating systems such as uC/OS have been used for PLCs and must meet real-time constraints. As PLCs have been widely used for industrial control systems and connected to the Internet, they have been becoming a main target of cyberattacks. In this paper, we propose an execution code sanitizer to enhance the security of PLC systems. The proposed sanitizer analyzes PLC programs developed by an IDE before downloading the program to a target PLC, and mitigates security vulnerabilities of the program. Our sanitizer can detect vulnerable function calls and illegal memory accesses in development of PLC programs using a database of vulnerable functions as well as the other database of code patterns related to pointer misuses. Based on these DBs, it detects and removes abnormal use patterns of pointer variables and existence of vulnerable functions shown in the call graph of the target executable code. We have implemented the proposed technique and verified its effectiveness through experiments.

A Study on the Programming/Application of PID Control Modules of a PLC (PLC의 PID제어 모듈의 프로그래밍 및 적용에 관한 연구)

  • 조도현;이창희;이상훈
    • Journal of the Korea Computer Industry Society
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    • v.2 no.4
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    • pp.425-434
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    • 2001
  • In this paper, a series of processes to configure a feedback control system by using a PID controller in a programmable logic controller (PLC). The PLC (SIMATIC S7-400) with a PID module (FM455C) is connected by online to an IBM PC with the Windows environment, which serves as a PLC programmer. PID controllers including P/PD/PI controllers have been designed in order to show design procedures, and finally, a PID controller for the plant of cart system. Performances of the control system have been investigated by the MATLAB simulation, the simulation in the PLC programmer. Physical performances have been recorded and examined for the real cart system.

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Channel Analysis of inside PLC (옥내 전력선 채널 분석)

  • Hong Duc-Pyo;Lee Jin-Mok;Kim Soo-Cheol;Choi Jae-Ho;Hong Hyun-Mun
    • Proceedings of the KIPE Conference
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    • pp.456-458
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    • 2006
  • Power line communication: PLC which easy to install at anywhere near outlet for electric machine. PLC uses transmission line for voltage of which is 60 Hz. Signals don't affect to electric machine in PLC because they are very small voltage. One of the important thing is the processes of adding signal to power line and extracting the signal from power line, the other is to choose the strong modulation method which sends signals long distance without loosing in PLC channel. but PLC channel have very high and variable noise and attenuation and then it is very hard to transmit optimally between the transmitter and the receiver. After all, impedance and noise problems of PLC channel must be overcame. Noises of 2 kinds which are AWGN abd impulse noise and attenuation are orated. To overcome the noise. Recently, Multi-carrier Modulation: MCM methods like as OFDM and DMT which are divide the channel into many sub-channel have been studied. those are powerful communication methods in PLC. In this paper, PLC channels made up of 3 numbers of noise and attenuation are simulated for getting BER by Matlab simulink.

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The Design and Implementation of a Mobile-agent System for SoftPLC (SoftPLC를 위한 모바일 에이전트 시스템의 설계 및 구현)

  • Bae, Hae-Gwang;Choi, Young-Hyun;Min, Gi-Sung
    • Proceedings of the Korea Information Processing Society Conference
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    • pp.31-34
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    • 2006
  • 최근의 PLC는 Ethernet 통신, Field Bus등 새로운 통신규약에 호환성을 갖고 있으며 점점 빠른 연산 속도의 초소형 PLC로 발전해 나가고 있고 공장 자동화와 FMS(Flexible Manufacturing System)에 따른 PLC의 요구는 과거 중규모 이상의 릴레이 제어반 대체 효과에서 현재 고기능화, 고속화의 추세로 소규모 정작 기계에서 대규모 시스템 설비에 이르기까지 적용되고 있다. 그러나 현재 사용되고 있는 PLC는 각 제조사마다 하드웨어형식은 유사하지만 소프트웨어형식인 제어 명령어들이 다르기 때문에 각각의 PLC마다 호환이 되지 않는다는 문제점을 가지고 있어 이 제어 명령어들의 호환성을 위한 솔루션이 필요하다. 이를 해결하기 위하여 본 논문은 IEC1131-3의 표준 언어를 중심으로 제어할 수 있는 Mo-aPLC라는 모바일 에이전트 기반의 softPLC시스템을 제안하였다. 이 시스템은 모바일 에이전트들이 지적 대리인으로서 IEC1131-3의 표준 언어를 제어시스템 제작자에게 활용되어 질 수 있는 코드인 IL언어로 변환하고 이를 랭귀지 프로그래머가 활용할 수 있는 코드인 표준 C코드로 변환하는 것이다. 이 시스템으로 인해 제어시스템 제작자와 랭귀지 프로그래머들이 활용할 수 있는 코드들이 생성되는 것과 표준 C코드로 변환함으로서 논리적인 디버깅(dubugging)이 용이하다는 것을 알 수 있었다.

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Altered PLCβ-1 expression in the gerbil hippocampal complex following spontaneous seizure

  • Lee, Saet-Byeol;Oh, Yun-Jung;Chung, Jae-Kwang;Jeong, Ji-Heon;Lee, Sang-Duk;Park, Dae-Kyoon;Park, Kyung-Ho;Ko, Jeong-Sik;Kim, Duk-Soo
    • BMB Reports
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    • v.44 no.9
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    • pp.566-571
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    • 2011
  • Although the phospholipase C (PLC)${\beta}$-1 isoform is associated with spontaneous seizure and distinctively expressed in the telencephalon, the distribution of PLC${\beta}$-1 expression in the epileptic gerbil hippocampus remains controversial. Therefore, we determined whether PLC${\beta}$-1 is associated with spontaneous seizure in an animal model of genetic epilepsy. In the present study, PLC${\beta}$-1 immunoreactivity was down-regulated in seizure-sensitive (SS) gerbils more than in seizure-resistant (SR) gerbils. The expression of PLC${\beta}$-1 within calretinin (CR)-positive neurons was rarely detected within the dentate hilar region of SS gerbils. PLC${\beta}$-1 immunoreactivity in the hippocampus was significantly elevated as compared to that in pre-seizure SS gerbil 3 h post-ictal. These findings suggest that alterations in PLC${\beta}$-1 immunoreactivity in the SS gerbil hippocampus may be closely related to the epileptic state of the gerbil brain and transiently elevated PLC${\beta}$-1 protein levels following seizure episodes. Such alterations may be compensatory responses in the SS gerbil hippocampus.