• 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.

• International Journal of Safety
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• v.3 no.1
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• pp.38-46
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• 2004

This paper introduces the software life-cycle V&V (verification and validation) tasks for the KNICS (Korea nuclear instrumentation and control system) project. The objectives of the V&V tasks are mainly to develop a programmable logic controller (PLC) for safety critical instrumentation and control (I&C) systems, and then to apply the PLC to developing the prototype of an engineered safety features-component control system (ESF-CCS) in nuclear power plants. As preparative works for the software V&V, various kinds of software plans and V&V task procedures have been developed according to the software life-cycle management. A number of software V&V tools have been adopted or developed to efficiently support the V&V tasks. The V&V techniques employed in this work include a checklist-based review and inspection, a requirement traceability analysis, formal verification, and life-cycle based software testing.

• KSBB Journal
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• v.20 no.3
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• pp.149-163
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• 2005

Recently preparative liquid chromatography (PLC) has been used more frequently to separate drugs and natural substances. This modern separation methodologies require reliable tools that perform on a high level in terms of efficiency and reproducibility. However, large-scale PLC easily tends to reduce the yield and purity of the product. To promote the separation efficiency of PLC, we need to properly understand the controlling effects of the process, which may enable to predict the process and to improve the design and operation of PLC. Progress in computer technology allows the use of sophisticated models, provided their parameters can be measured. Some hardwares as well as softwares for PLC were already commercially available. In this work, the separation characteristic of PLC will be reviewed and compared on both the software and the hardware.

• Journal of KIISE:Software and Applications
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• v.32 no.2
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• pp.108-118
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• 2005

The software of the nuclear power plant digital control system is a safety-critical system where many techniques must be applied to it in order to preserve safety in the whole system. Formal specifications especially allow the system to be clearly and completely specified in the early requirements specification phase, therefore making it a trusted method for increasing safety. In this paper, we discuss a systematic method, which generates PLC-based FBD programs from the requirements specification using NuSCR, a formal requirements specification method. This FBD programs takes an important position in design specification. The proposed method can reduce the possible errors occur in the manual design specification, and the software development cost and time. To investigate the usefulness of our proposed method, we introduce the fixed set-point rising trip example, a trip logic of BP in DPPS RPS, which is presently being developed at KNICS.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.801-802
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• 2006

The present study purposes to develop HMI software that runs on Windows CE .NET platform without being bound to specific HMI equipment and accesses data in PLC equipment through interoperation with an OPC-DA server. As the OPC-DA server reads data in PLC equipment, HMI system does not need to be configured differently for different equipments. In addition, when the interface environment of specific equipment changes, it does not require the application of new equipment or the change of communication protocol. As HMI system runs on Windows CE .NET platform, it can be configured using common embedded devices based on Windows CE .NET platform. HMI software reads data in PLC equipment through RS-232C communication interface. In addition, because it connects to an OPC-DA server through Ethernet communication interface, it can access data in PLC equipment as long as Ethernet is usable.

• Nuclear Engineering and Technology
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• v.38 no.3
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• pp.259-276
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• 2006

As the use of digital systems becomes more prevalent, adequate techniques for software specification and analysis have become increasingly important in nuclear power plant (NPP) safety-critical systems. Additionally, the importance of software verification and validation (V&V) based on adequate specification has received greater emphasis in view of improving software quality. For thorough V&V of safety-critical systems, V&V should be performed throughout the software lifecycle. However, systematic V&V is difficult as it involves many manual-oriented tasks. Tool support is needed in order to more conveniently perform software V&V. In response, we developed four kinds of computer aided software engineering (CASE) tools to support system specification for a formal-based analysis according to the software lifecycle. In this work, we achieved optimized integration of each tool. The toolset, NuSEE, is an integrated environment for software specification and V&V for PLC based safety-critical systems. In accordance with the software lifecycle, NuSEE consists of NuSISRT for the concept phase, NuSRS for the requirements phase, NuSDS for the design phase and NuSCM for configuration management. It is believed that after further development our integrated environment will be a unique and promising software specification and analysis toolset that will support the entire software lifecycle for the development of PLC based NPP safety-critical systems.

• Journal of Korea Multimedia Society
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• v.20 no.3
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• pp.491-499
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• 2017

The Information & Communication Technology (ICT) and the Internet of Things (IoT) have become the major issues in Republic of Korea recently. While RS-232, Zigbee, and WiFi-related technologies are used in the ICT-based systems, we focus on the Power Line Communication (PLC) in this paper. By carrying out OPNET simulations, we've implemented the PLC Router Node Model, PLC Terminal Node Model, PLC Link Model, and PLC Palette Model and executed the simulations arranging 20 holds within the range of 400m (20m apart). As a result, we confirmed that the slient node problem had occurred at the point of 200m-2000m (as of 2016) distance preventing further communications. However, the control group, by contrast, was able to carry out the communications by installing a router. We expect that this paper will contribute to the development of a foundation technology which will saves costs by performing the simulation prior to building actual large-scale ICT Complex in the future work.

• Journal of KIISE:Software and Applications
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• v.37 no.1
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• pp.54-59
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• 2010

Special-purpose microcontrollers PLCs have been widely used in the area of industrial automation. For the research of analysis and verification for PLC programs, first of all we have to specify formal sematics of PLC programming languages. This paper defines formally the operational semantics of LD language. After we transform the graphical language LD into its textual representation Symbolic LD, we give semantics of Symbolic LD since LD language is a graphical language. This paper defines the natural sematics of Symbolic LD and formalizes it in Coq proof assistant.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.84.2-84
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• 2001

To remove the logical error inexpensively, in this paper, we propose new concept of VPLF(Virtual PLC Framework) which consists of VPLE(Virtual PLC Editor), Virtual Machine(Virtual Machine), VMC(Virtual Machine Control panel), Virtual PLC Program Editor(VPLPE) and Object Inspector. VPLC is for PLC hardware and software and VM is for the target to be controlled. VPLC has an individual editor and the screen of configuration. With using individual editor in VPLC, we can edit and compile to PLC ladder program. In VM, there are many kinds of object for machine elements, actuator, sensor and so on. The VPLC and VM are interlinked each other and controlled by the PLC program in real time. So, we can get the powerful realization as the machine is ...

• Journal of the Korea Society of Computer and Information
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• v.27 no.1
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• pp.61-67
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• 2022

In this paper, we propose a model that can convert some of the simulation program resources to a mobile environment. Recently, smart factories that use PLCs as controllers in the manufacturing industry are rapidly becoming widespread. However, in the situation where it is difficult to operate due to the shortage of PLC operation personnel, the actual situation is that a platform for PLC operation education is necessary. Currently most PLC-related educational platforms are based on 2D, which makes accurate learning difficult and difficult. When a simulation program is applied to distance learning in a general PC environment, many elements are displayed on the monitor, which makes screen switching inconvenient. Experiments with the proposed model confirmed that there was no frame deterioration under general circumstances. The average response time by the request frame was 102 ms, and it was judged that the learner was not at the level of experiencing the system delay.