• Korean Journal of Computational Design and Engineering
• /
• v.14 no.3
• /
• pp.176-185
• /
• 2009

Modern manufacturing systems consist of highly automated manufacturing devices, and they are controlled by complicated PLC programs. To make sure the achievement of the control objectives of a manufacturing system, it is very important to monitor the dynamic system behaviors of the manufacturing system. In this paper, we propose a monitoring methodology of a PLC program based on the Software In the Loop Simulation(SILS), which makes use of the time gap information between PLC signals. The errors relevant with PLC signals can be found using the proposed methodology, comparing a normal PLC signal trajectory with a target PLC signal trajectory. The proposed methodology has been implemented and tested with simple examples.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
• /
• 2001.05a
• /
• pp.26-31
• /
• 2001

Petri nets(PN) have been introduced as a poweful analyzing and design tool for the discrete systems such as sequential control systems. However, one of the important problems in its applications is that the model can not be analyzed easily when we deal with large scale systems because of increase of the number of components of the systems. To overcome this problem, some methods for dividing or reducing of PN have been suggested. In this paper, an approach for hierarchical expression of PN based on Sequential Function Chart(SFC) and Bottom Up oriented Mehodology(BUM) is proposed. Especially, some definition and rules are defined in order to divide and compose sub PN. A measuring tank system will be described as a typical kind of discrete systems and modeled by some sub PN based on the SFC and BUM by the proposed method in this paper.

• Proceedings of the KIEE Conference
• /
• 1998.07g
• /
• pp.2390-2392
• /
• 1998

In this paper, we discuss the development of monitoring system with data process equipment which transfers data from Remote Terminal Unit(RTU) to monitoring computer. The RTUs sense temperature, pressure and PLC(Programmable Logic Controller) nodes conditions of scrubber in semiconductor manufacture processing. The data Process equipment is connected every RTU and a monitoring computer through serial communication. This equipment receives informations from RTU, process data, and transfers them to monitoring computer. To avoid congestion in data communication, task scheduling algorithm used RT O/S(Real-Time Operating System) is embedded in ROM which is a part of data Process equipment.

• Proceedings of the KIEE Conference
• /
• 1998.11b
• /
• pp.475-477
• /
• 1998

In this paper, the implementation of a virtual Plant simulator for the PLC programming is presented. A virtual plant simulator that replaces function of transducers (e.g. pumps and valves) consists of a personal computer and a PLC(Programmable logic controller). Input/output conponents are edited on the monitor and are operated as the field transducers. The timing process for input/output components is analyzed. The data flow between a PLC system and a virtual plant simulator is carried out.

• Proceedings of the KIEE Conference
• /
• 1995.07b
• /
• pp.880-882
• /
• 1995

The systematic function of the PLC (Programmable - Logic Controller) has been enhanced immensely due to the various special modules that consist of the conventional I/O control contants plus special function, which enables the flexible application to highly advanced systems. Position control module is one of the various PLC special module. In this paper, we proposed new synchronized operating method and implemented 8 - axis servo control system. The validity of proposed method is verified througth experimental results and it will be possible to expand 32 - axis servo control system by RS - 485 communication spec.

• Journal of Communications and Networks
• /
• v.18 no.1
• /
• pp.40-49
• /
• 2016

In this paper, we present a symbol-level iterative source-channel decoding (ISCD) algorithm for reliable transmission of variable-length codes (VLCs). Firstly, an improved source a posteriori probability (APP) decoding approach is proposed for packetized variable-length encoded Markov sources. Also proposed is a recursive implementation based on a three-dimensional joint trellis for symbol decoding of binary convolutional codes. APP channel decoding on this joint trellis is realized by modification of the Bahl-Cocke-Jelinek-Raviv algorithm and adaptation to the non-stationary VLC trellis. Simulation results indicate that the proposed ISCD scheme allows to exchange between its constituent decoders the symbol-level extrinsic information and achieves high robustness against channel noises.

• Proceedings of the KIEE Conference
• /
• 2005.07c
• /
• pp.2465-2467
• /
• 2005

In this paper, we propose the system that can monitor and control the camera in the remote place using the PDA. The server PC attached to the PLC (Programmable Logic Controller) acquires the current status (On/Off) of the devices through the RS-232 serial communications. Also, the moving image frames captured from the wireless camera is compressed in the JPEG format and is stored in the server. The PDA, which is connected to the server through wireless internet, receives the data about the status of the devices and controls the devices according to the circumstances of them. Also, it can receive the images from the server simultaneously. So, we can monitor and control the specified area in the remote place using the PDA through the wireless communication.

• Proceedings of the KIEE Conference
• /
• 2003.07d
• /
• pp.2432-2434
• /
• 2003

노내 중성자 분포 측정 설비는 원자로 내부의 중성자 분포를 측정하는 설비로서 원자로 내부를 이동하는 검출기의 구동 메커니즘 제어와 측정 데이터 취득을 위한 제어시스템이 요구된다. 이 설비는 발전소 건설 당시 도입되었던 제어시스템으로 운전되고 있으나 노후되어 디지털 제어시스템으로의 설비 개선 연구가 착수 되었다. 개발된 제어시스템은 산업표준 Programmable Logic Controller 및 소프트웨어 기반으로 설계되어 기능개선, 설계변경 및 예비품 확보에 유연하게 대처할 수 있고, 진보된 검출기 구동 메커니즘 제어와 검출기 데이터 취득 기능을 통하여 측정 작업의 완전 자동화가 가능하다. 특히, 다양한 진단 기법을 통하여 작업상황 및 설비의 상태를 파악하여 필요한 보호기능과 경보기능을 제공함으로써 설비의 안정적 운영과 정비가 편리하다. 현재 개발된 시스템은 고리1호기에 설치되어 주기적으로 노내 중성자 분포 측정 작업을 수행하고 있다.

• Proceedings of the KIEE Conference
• /
• 2003.07b
• /
• pp.726-728
• /
• 2003

A linear induction motor conveyance system with longitudinal and transverse rails is manufactured. which is controlled by programmable logic controller(PLC). The linear induction motor has a cage-type secondary and the total number of the installed primaries is 10. Four secondaries are installed on the below surface of the moving carrier. In this paper, the developed conveyance system is introduced and its PLC control characteristics for the longitudial and transverse moving directions are presented.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2006.05a
• /
• pp.462-466
• /
• 2006

In industrial control system used by Programmable Logic Controller(PLC), Ladder Diagram(LD) is the about widely utilized and plays an important role in industrial control system. But recently, the study about Sequential Function Chart(SFC) is performed actively. When we program by SFC, generally, we design one routine from start to end. This method is difficult to design, and we often make mistakes. In this paper, we propose the method that we compose each sub-system after we design each sub-system and we analysis the difference of the method used this paper from conventional method.