• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.10
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• pp.4618-4625
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• 2011

This paper suggests a specific model that could efficiently improve the interaction and the interface between MES(Manufacturing Execution System) server and POP(Point Of Production) Terminal through RFID(Radio Frequency Identification) system in Automative Module Assembly Line. The proposed model shows that the new method by RFID can more efficiently perform to receive work order informations and transmit work performances, compared with the current approach by proximity sensor. As a result of the certain test among the MES server, RFID system, PLC(Programmable Logic controller) and POP terminal, it is noted in case of the automatic control by RFID that the effects of proposed model are as follows; (a) While the processing time per truck for carrying by the current method was 10 minutes, the processing time by the new method was 1 minutes. (b) While the error rate by the current method was 20 %, the error rate by the new method was 1 %.

• Journal of Astronomy and Space Sciences
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• v.17 no.2
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• pp.211-220
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• 2000

Korea Astronomy Observatory(KAO) is working to retrofit its 1m robotic telescope in collaboration with a company (ACE, Astronomical Consultants & Equipment). The telescope system is being totally refurbished to make a fully automatic telescope which can operate in both interactive and fully autonomous robotic modes. Progress has been made in design and manufacturing of the telescope mount, mechanics, and optical performance system tests are being made for re-configured primary and secondary mirrors. The optical system is designed to collect 80% incident light within 0.5 arcsec with f/7.5 Ritchey-Chretien design. The telescope mount is an equatorial fork with a friction drive system. The design allows fully programmable tracking speeds with typical range of 15 arcsec/sec with accuracy of $\pm5$ arcsec/hour. The mount system has integral pointing model software to correct for refraction, and all mechanical errors and misalignments. The pointing model will permit positioning to better than 30 arcsec RMS within $75^{\circ}$ from zenith and 45 arcsec RMS elsewhere on the sky. The software is designed for interactive, remote and robotic modes of operation. In interactive and remote mode the user can manually enter coordinates or retrieve them from a computer file. In robotic mode the telescope controller downloads the coordinates in the order determined by the scheduler. The telescope will be equipped with a CCD camera and will be accessible via the internet.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.9
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• pp.125-132
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• 2002

We use a compound-cam twin arm structure and random tool access method to achieve a faster ATC (Automatic Tool Changer) system for the accurate position and rotation control of a tool magazine and an exchange am. Based on the data obtained from various sensors, it is possible to follow the sequence of commands in each control step for an exchange arm. However, it is not so easy to reduce the exchange time of the system because of the slow responses of the sensors and execution mode delays of PLC (Programmable Logic Controller) scan time. In this paper, we propose a new programmed limit-switch position control method to obtain the shortest possible delays for the random tool access method and compound-cam twin arm structure. With some experimental results, we have achieved below 0.9sec tool exchange time with the proposed method.

• 한국가시화정보학회:학술대회논문집
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• 2004.12a
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• pp.1-13
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• 2004

A scanning stereo-PIV system was developed to measure the three-dimensional distribution of three-component velocity in a turbulent round jet. A laser light beam produced by a high repetition rate YLF pulse laser was expanded vertically by a cylindrical lens to form a laser light sheet. The light sheet is scanned in a direction normal to the sheet by a flat mirror mounted on an optical scanner, which is controlled by a programmable scanner controller. Two high-speed mega-pixel resolution C-MOS cameras captured the particle images illuminated by the light sheet, and stereoscopic PIV method was adopted to acquire the 3D-3C-velocity distribution of turbulent round jet in an octagonal tank filled with water. The jet Reynolds number was set at Re=1000 and the streamwise location of the measurement was fixed at approximately x = 40D. Time evolution of three-dimensional vortical structure, which is identified by vorticity, is visualized. It revealed that the existence of a group of hairpin-like vortex structures was quite evident around the rim of the shear layer of the jet. Turbulence statistics shows good agreement with the previous data, and divergence of a filtered (unfiltered) velocity vector field was $7\%\;(22\%)$ of root-me an-squared vorticity value.

• Journal of Biosystems Engineering
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• v.29 no.3
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• pp.243-250
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• 2004

본 연구에서는 국내 미곡도정공장의 도정기계 작동상태와 가공된 발 품질의 원격감시를 위해서 인터넷기반 감시시스템을 개발하고자 하였다. 인터넷 감시시스템은 Laboratory Virtual Instrument Engineering Workbench(Lab VIEW)를 이용하여 개발되었으며 Hypertext Transfer Protocol(HTTP)을 제공할 수 있는 중앙서버, 현장제어용 Programmable logic controller (PLC) 및 각종 센서 등으로 구성되었다. 비상상태를 대비하기 위하여 도정기계를 원격으로 제어(ON/OFF)할 수 있도록 제어알고리즘을 설계하였다. 개발된 인터넷기반 감시시스템은 미곡 도정공장에 설치한 모든 도정기계의 작동상태, 백미 탱크내의 백미 무게와 백미의 온도 및 평형상대습도를 실시간으로 감시할 수 있었으며, 원격으로 측정한 백미탱크내의 평형온도 및 평형상대습도를 이용하여 백미의 함수율도 예측할 수 있었다. 거리 및 인터넷속도에 의해 발생된 시간지연의 측정과 원격으로 수집된 자료의 검증을 통해 인터넷 감시시스템의 성능을 평가하였다. 인터넷상의 시간지연(서울-광주간)은 약 1.2$\pm$0.2s 이었다.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1994.05a
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• pp.64-77
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• 1994

현재 건설중인 3톤/일 규모의 석탄가스화기 운전제어를 위한 콘트롤시스템은 각종 하드웨어와 소프트웨어로 구성된다. 하드웨어는 운전자가 접하게되는 컴퓨터 화면(Operator Console), 운전 제어용 판넬(Hardwired Console), 본 시스템의 핵심인 콘트롤러(PLC; Programmable Logic Controller), 폭발성가스와 분진이 있는 환경하에서의 안전운전을 위한 본질안전 장벽(Intrinsic Safety Barrier) 및 운전정보 수집과 운전 제어를 위한 각종 전/계장품(Field Instrument) 등으로 구성된다. 본 시스템에 포함되는 소프트웨어에는 운전자와 콘트롤러간의 통신을 위한 운전제어화면(GUI;Graphical User Interface), 전체적인 제어를 위한 콘트롤로직(Control Logic)등이있다. 한편 각종 펌프 및 보일러 등 보조설비로의 전기공급을 위한 MCC(Motor Control Center)도 하나의 구성원이 된다. 본 논문은 석탄가스화 반응기의 운전에 관한 전반적인 검토와 콘트롤시스템을 구성하는 각 요소와 각각의 특징 및 그 개발 현황에 대한 검토를 그 내용으로 한다. 본 연구과제를 통해 제작, 설치될 석탄가스화기는 차세대 발전 시스템으로 주목을 받고있는 석탄가스화 복합발전시스템의 핵심부분으로, 본 반응장치의 제어에 관한 경험은 상용 규모의 석탄가스화 반응기에도 유사하게 적용될 것으로 기대된다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.10
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• pp.5134-5139
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• 2013

Ladder Diagram(LD) or Sequential Function Chart(SFC) is used for the design of complex modern control system with Programmable logic controller(PLC). LD is the most widely utilized among PLC standard language. But recently, SFC is used frequently. SFC is very easy to grasp the sequential flow of control logic but is difficult for describing combinational logic. When the interrupt factor is occurred, the main program is stopped. And after the interrupt program is completed, the main program is restart. Therefore the more complex the interrupt program, the main program is interrupted downtime will be that much longer. In this paper, we propose the method for interrupt implementation without the dwell time of the main program by SFC language and confirm his feasibility through the simulation.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.5
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• pp.1-11
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• 2000

A control system using a programmable logic controller (PLC) has been developed for a dual tower dryer (DTD) in a canadian deuterium natural uranium reactor (CADND) type nuclear power plant. This system will replace the existing DTD control system which was implemented with mechanical timers and relays. The new control system makes it possible for an operator to perform more precise time and dew point control for the DTD, thanks to the high efficiency and flexibility of the PLC. The operational cost for the control system is much reduced compared to the existing system.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.6
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• pp.689-694
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• 2014

An SPLC (Safety Programmable Logic Controller) must be designed to meet the highest safety standards, IEEE 1E, and should guarantee a level of fault-tolerance and high-reliability that ensures complete error-free operation. In order to satisfy these criteria, I/O modules, communication modules, processor modules and bus modules of the SPLC have been configured in triple or dual modular redundancy. The redundant modules receive the same data to determine the final data by the voting logic. Currently, the processor of each rx module performs the voting by deciding on the final data. It is the intent of this paper to prove the improvement on the current system, and develop a voting system for multiple data on a system bus level. The new system bus protocol is implemented based on a TCN-MVB that is a deterministic network consisting of a master-slave structure. The test result shows that the suggested system is better than the present system in view of its high utilization and improved performance of data exchange and voting.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.6
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• pp.952-958
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• 2009

The International Maritime Organization (IMO) has adopted the ballast water management convention at a diplomatic conference in early 2004 that all ships should be equipped with a treatment system from 2010 gradually. In this paper, the disinfection characteristic of ultra-violet (UV) rays was studied and a ballast water treatment system (BWTS) which can treat $50m^3$/h sea water was manufactured. The system consists of a disinfection chamber with six 3.5 kW UV lamps which are operated by magnetic ballasts, a programmable logic controller (PLC) and set of pipe lines. The biological disinfection efficacy of the prototype BWTS was evaluated following the IMO rules using zooplankton such as Artemia and Rotifer species for the size over $50{\mu}m$, and phytoplankton such as Tetraselmis and Thalassiosira species for the size between 10 to $50{\mu}m$. From the experimental results, the disinfection efficacy was 99.99 % that meets the IMO requirement. However, more studies on an energy saving system are needed because the consumption power of the prototype system is as high as over 21 kWh for $50m^3$/h.