• Proceedings of the KIEE Conference
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• 1998.07g
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• pp.2402-2404
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• 1998

This paper proposes a translation method that converts ladder diagrams to binary executable codes for PLC (programmable logic controller)s. A PLC based on general purpose DSP(digital signal processor) validates the method. We performed a benchmark on the system that compares the execution time of the interpretation method and ours. Experimenal result shows how fast this method executes programs that consist of codes generated.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.752-755
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• 1997

In this paper, a scheduling algorithm is proposed for a programmable logic controller(PLC) with remote I/Os, assuming the multi-tasking facilities. Since sequence programs are executed on the application processor and I/O data are transmitted by the network processor concurrently, the proposed algorithm schedules the data transmission as well as the sequence program execution. The suggested algorithm guarantees the bounded WCRT(worst case response time), which is the one third of the WCRT in the absence of scheduling. Computer simulation shows that the algorithm can be easily applied to a real PLC without critical constraints on utilization of resources and inter-relation among tasks.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.10
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• pp.1117-1123
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• 2014

Nuclear industries have faced unfavorable circumstances such as an obsolescence of the instrumentation and control system, and therefore nuclear society is striving to resolve this trouble fundamentally. FPGAs are currently highlighted as an alternative means for obsolete control systems. Because of the obsolescence-unaffected characteristics, FPGA should be highly reliable in order to be a replacement for PLC (Programmable Logic Controller). Therefore, it is necessary to establish a software development aspect strategy that enhances the reliability of an FPGA-based controller. The reliability analysis including the MTBF (Mean Time Between Failures) is carried out based on the MIL-HDBK-217F. MTBFs are compared with the FPGA-based controller COMMON-Q PLC. As an analysis result, it shows that the reliability of the FPGA-based controller is better than or equal to that of PLC.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2000.12a
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• pp.209-212
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• 2000

This paper describes the design and implementation of a hard- wired AGV controller using CPLD(Complex Programmable Logic Device). The proposed controller manages a guidance equipment, motor and I/O sequence controller for a self-control traveling. Compared with a conventional $\mu$-processor, the CPLD controller using a hard-wired control method can reduce a difficult programming process. Also, the total costs of production are reduced, such as development time, product's size and difficulty because memory, combinational logic and sequential logics are implemented by CPLD. The Controller designed using behavioral description method with VHDL and was synthesized by MAX＋Plus II of the ALTERA co. We implemented controller using EPF10K10LC84-4 device.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.1
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• pp.47-52
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• 2000

Redundant programmable logic controllers are used in practice with the aim of achieving a higher degree of availability or fault tolerance. Redundancy system is fault tolerant programmable logic controller for machine and plant. It is event synchronized master-standby system with a 2 channel(1-out-of-2) structure. A data link connects line the master to the standby controller.Fault tolerant systems should always be used when it is necessary to keep the probability of a total control system failure to a minimum. The objective of using high availability programmable logic controller is a reduction of losses of fault tolerant system are quickly compensated by the avoidance of loss of production.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.4
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• pp.265-269
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• 2009

Formal specification plays important roles in guaranteeing software safety of safety-critical systems such as nuclear power plant's digital control systems. We had developed a technique [1] which synthesizes Function Block Diagram(FBD) programs from NuSCR formal requirements specifications, but it did not be used widely as it had no automatic tool support. FBD is one of the programming languages for Programmable Logic Controllers(PLC) based system. This paper introduces a CASE tool, NuSCRtoFBD, developed to automate the synthesis procedure. The CASE tool NuSCRtoFBD can reduce a number of errors occurred in the process of manual FBD programming.

• Journal of Korea Society of Digital Industry and Information Management
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• v.16 no.1
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• pp.99-109
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• 2020

In the past, conservative concepts have been applied in terms of the characteristic of nuclear power plants(NPPs), resulting in analog-based equipment and closed networks. However, as digital technology has recently been applied to the design, digital-based facilities and communication networks have been used in nuclear power plants, increasing the risk of cybersecurity than using analog-based facilities. Nuclear power plant facilities are divided into a safety system and a non-safety system. It is essential to identify the difference and cope with cybersecurity threats to the safety system according to its characteristics. In this paper, we examine the cybersecurity regulatory guidelines for safety systems in nuclear power plant facilities. Also, we analyze cybersecurity threats to a programmable logic controller of the safety system and suggest cybersecurity requirements be applied to it to respond to the threats. By implementing security functions suitable for the programmable logic controller according to the suggested cybersecurity requirements, regulatory guidelines can be satisfied, and security functions can be extended according to other system requirements. Also, it can effectively cope with cybersecurity attacks that may occur during the operation of nuclear power plants.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.11a
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• pp.986-988
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• 2022

본 연구는 전기전자기기를 비접촉 ON/OFF제어와 기기의 수명연장을 개선 시키기위해 전기전자기기에 다용도로 활용되는 제어컨트롤러 모듈인 PLC(Programmable Logic Controller)의 입력측에 마이크로컨트롤러와 AI 비젼카메라를 설치하여, 비접촉 ON/OFF 제어에 관한 아이디어 제시하고, 이를 기반으로 구현하였다. 구현 결과 단순 I,O 신호에 의한 제어와는 다르게 이미지 인식을 구체적으로 구분하여 센싱하고, 다양한 인식 구분을 위해 머신러닝 기반으로 AI 비젼카메라를 학습시킨 결과 물체 및 색깔 구분에 따라서 전기전자기기를 제어 할 수 있었으며, 접촉이 아닌 비접촉 ON/OFF 제어가 간단하게 구현되어, 전기전자기기 수명연장도 기대 할 수 있게 되었다..

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.1110-1115
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• 1991

Tne mathematical modeling and analysis results of a dataflow logic solving processor(DFLSP) for programmable logic controller(PLC) are proposed in this paper. The logic program language is formalized using a dataflow graph model. From this dataflow graph, the instruction precedence relationship, and deadlock problems, which are major properties of a logic program, are described.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.8
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• pp.834-841
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• 2006

Recently, many enterprises are installing AMSs(Automated Manufacturing Systems) for their competitive advantages. As the level of automation increases, proper design and validation of control logic is a imperative task for the successful operation of AMSs. However, current discrete event simulation methods mainly focus on the performance evaluation. As a result, they lack the modeling capabilities for the detail logic of automated manufacturing system controller. Proposed in this paper is a method of validation of the controller logic for automated material handling system using an object-oriented design and simulation. Using this method, FA engineers can validate the controller logic easily in earlier stage of system design, so they can reduce the time for correcting the logic errors and enhance the productivity of control program development Generated simulation model can also be used as a communication tool among FA engineers who have different experiences and disciplines.