• 제어로봇시스템학회논문지
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• 제20권7호
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• pp.741-749
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• 2014

This paper proposes a machine vision module for PLCs (Programmable Logic Controllers). PLC is the industrial controller most widely used in factory automation system. However most of the machine vision systems are based on PC (Personal Computer). The machine vision system embedded in PLC is required to reduce the cost and improve the convenience of implementation. In this paper, we newly propose a machine vision module based on PLC. The image processing libraries are implemented and integrated with the PLC programming tool. In order to interface the libraries with ladder programming, the ladder instruction set was also designed for each vision library. By use of the developed system, PLC users can implement vision systems easily by ladder programming. The developed system was applied to sample inspection system to verify the performance. The experimental results show that the proposed system can reduce the cost of installing as well as increase the ease-of-implementation.

• 융합신호처리학회논문지
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• 제20권3호
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• pp.118-124
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• 2019

최근 산업현장에서는 생산성, 품질, 고객 만족도를 향상시키기 위해 정보통신기술(ICT)을 기반으로 한 스마트 팩토리 체제로 전환하고 있다. 스마트 팩토리를 실현함에 있어 가장 중요한 장치는 무인 반송차(AGV)이며, AGV의 도입이 증가하고 있다. 일반적으로 AGV은 범용 PLC를 이용하여 개발하고 있으나, 범용 PLC로 개발된 AGV의 가격은 고가이며, 부피 또한 크다. 한편, 산업현장에서는 작업장의 공간적 제약 때문에 소형화, 용이한 재구성 등이 가능한 저가의 AGV를 요구하고 있다. 따라서 본 연구에서는 이러한 문제점을 해결하기 위해 PLC 내장형 AGV 제어기의 설계법을 제안하고, 그 성능을 평가하였다. 그 결과, 우수한 속도제어와 주행 정밀도(속도제어 오차=0.021[m/s], 주행자세제어의 평균오차 = 2.1[mm])를 보였다. 이와 같이 제안된 AGV 제어기를 산업현장에 적용한다면, 저비용으로 소형화와 재구성 등이 가능할 것이다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 B
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• pp.1189-1192
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• 1996

In this paper, a fault diagnosis method is proposed for self-diagnostics of PLC(Programmable Logic Controller), process controller in industrial fields, and diagnosis of its external devices such as sensors and actuators. The aim of this research is proposition of systematic method of fault diagnosis of PLC control system and development of its equipment. A PLC fault diagnosis algorithm consists of self-diagnostics given by PLC makers, Inpuot/Output tracking method by analyzing sequence PLC programs, searching method of past fault cases in database using an expert system, and diagnosis of PLC units such as CPU, DI, and DO board. Finally usability of PLC fault diagnostic system is verified by testing a MELSEC PLC.

• 정보보호학회논문지
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• 제29권2호
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• pp.365-375
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• 2019

PLC(Programmable Logic Controller)는 안전 지향 제어시스템(safety-critical control system)을 위한 실시간 임베디드 제어 애플리케이션들을 지원하는 고신뢰성의 산업용 디지털 컴퓨터이다. PLC의 실시간 제약조건을 만족시키기 위하여 uC/OS 등의 실시간 운영체제들이 구동되고 있다. PLC들이 산업제어 시스템 등에 널리 보급되고 인터넷에 연결됨에 따라, PLC 시스템을 대상으로 한 사이버 공격들이 증대되고 있다. 본 논문에서는, 통합 개발 환경(IDE)에서 개발된 프로그램이 PLC로 다운로드 되기 전에 실행 코드를 분석하여 취약성을 완화시켜 주는 "실행코드 새니타이저(sanitizer)"를 제안한다. 제안기법은, PLC 프로그램 개발 중에 포함되는 취약한 함수들과 잘못된 메모리 참조를 탐지한다. 이를 위해 취약한 함수 DB 및 이상 포인터 연산과 관련된 코드 패턴들의 DB를 관리한다. 이들 DB를 기반으로, 대상 실행 코드 상에 취약 함수들의 포함 여부 및 포인터 변수의 이상 사용 패턴을 탐지 제거한다. 제안 기법을 구현하고 실험을 통해 그 유효성을 검증하였다.

• 산업공학
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• 제18권4호
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• pp.412-417
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• 2005

This paper describes the development of on-line Programmable Logic Controller(PLC) laboratories to teach the detailed operation of a PLC using distance learning approach. The PLC has become a key component to provide intelligence for machines in CIM environment. This study introduces a case study that teaches PLC programming in distance learning environment. The study describes the contents of PLC laboratories and workstation set ups. The study concludes with problems found and proposes the ways to improve the on-line laboratories.

• 산업경영시스템학회지
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• 제19권37호
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• pp.171-178
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• 1996

The programmable logic controller(PLC) programming has been manually carried out, which might cause the productivity decrease by omission and repetition of instruction. Recently, the knowledge-based automatic programming system is introduced. In the system, input/output(I/O) addresses are input by user. In this study, we developed the prototype system for automatic I/O addressing using knowledge-based technology, With the developed system, the PLC addressing task can he consistently and effectively performed.

• 한국CDE학회논문집
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• 제14권4호
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• pp.225-233
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• 2009

The objective of this paper is to examine a construction method and verify PLC logic using the logical modeling and simulation of a virtual plant has complex manufacturing system and the domain of application is car body assembly line of automotive industrial operated by PLC Program. The proposed virtual plant model for the analysis of the construction method consists of three types of components which are virtual device, intermediary transfer and controller is modeled by logical model but it the case of the verification of PLC program, HMI and PLC logic in the field substitute for the controller. The implementation of the proposed virtual plant model is conducted PLC Studio which is an object-oriented modeling language based on logical model. As a result, proposed methods enable 3D graphics is designed in the analysis step to use for verification of PLC program without special efforts.

• 한국생산제조학회지
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• 제22권2호
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• pp.331-336
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• 2013

The purpose of this study is to visualize the characteristics of ER fluids as preceding step of developing 3 port ER valves. As the strength of the electric field increases, more clusters in flow are made and these clusters are thought to be the reasons of the load flow rate being increased and the outlet flow rate being decreased. The ER Valves and load and outlet flow rate check method are considered to be applied to the fluid power control system. Using the manufactured pressure control valve, a one-link manipulator with FHA in robot system is driven. As a result, it is experimentally confirmed that the pressure control valve using ER fluids is applicable to use in driving actuator. If it applies characteristics of the ER fluids, it will be able to apply in the control system for the ER Valve which occurs from industrial controller(PLC).

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.575-579
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• 2005

In this paper, the development of an IMM(Injection Molding Machine) controller is discussed. Presently, the Mold Close and Open Control Method of a toggle-type IMM is open-loop control. Through the development, a PC based control system was built instead of an existing controller and a closed-loop control replaced the previous control method by using PC based PLC. To control the nonlinear system of toggle type clamping unit, a fuzzy PI control algorithm was selected and it was programmed by an IL(Instruction List) and a LD(Ladder Diagram) on a PC based PLC. The application of fuzzy algorithm as the control method was also considered to change a control object like a mold replacement or an additional apparatus. For the development of an IMM controller, PC based PLC of PCI card type, distributed I/O modules with CANopen and Industrial PC and HMI (Human Machine Interface) software were used.

• 한국산학기술학회논문지
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• 제10권12호
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• pp.3574-3580
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• 2009

본 논문에서는 IEC 61131-3 국제표준언어에 근거한 PLC 프로그래밍 개발환경을 지원해 주는 임베디드 모션 제어기를 개발하였다. 이 모션제어기에는 모션시스템 개발자가 PC 개발환경은 물론, PLC 개발환경에서도 손쉽게 모션제어 프로그래밍이 가능하도록 IEC 61131-3 개발 도구인 CoDeSys가 탑재되었으며, 직선 및 원호보간 제어와 같은 다양한 모션제어 함수들이 PLCopen 표준에 부합되는 모션 펑션블록으로 구현되었다. 또한 실시간 운영체제하에서 이더넷 기반 원격제어 및 모션 프로그래머를 위한 모션 시뮬레이터가 구현되었다.