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Safety enhancement for basic process control using 4-20 milliampere signal transmission
(2021-08-01)
Julsereewong, Amphawan
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Muangmool, Phongphiphat
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Thepmanee, Teerawat
To enhance safety of basic process control using traditional 4-20 mA current loops with/without transmitting a return signal of actual actuator position back to a host, this article presents a useful technique to provide fault-state and fault-recovery actions in four patterns. The proposed technique is a design of control drawings configured in a distributed control system (DCS) host for conventional proportional-integral-derivative (PID) loops with/without feedforward path to improve actions of the control loops in response to sensor and actuator failures. The configuration design based on functions of failure status propagation and failure mode shedding for eight control drawings that contain software function blocks for running on the DCS host modeled CENTUM VP is described. Simulation results by employing the DCS virtual test function verify that all designed control drawings can successfully perform the desired fault-state and faultrecovery actions for process safety enhancement.
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Comparative analysis between control in the host and control in the field in terms of safety and availability for foundation fieldbus-based process control
(2018-04-01)
Julsereewong, Amphawan
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Whatphat, Nopthawach
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Sangsuwan, Thaksin
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Chanwutitum, Jirasak
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Thepmanee, Teerawat
Design work of process control to provide necessary performance requirements must be based on capabilities and limitations of the technology used. This paper aims at analyzing possible safety and availability enhancements of basic process control based on Foundation Fieldbus (FF) technology in which the control function blocks can be assigned either in the host system controller, called ‘Control in the Host’ (CIH), or in the field devices, called ‘Control in the Field’ (CIF). Implementing the control loops with CIH and CIF strategies for water tank process is utilized as a case study to demonstrate the proposed analysis. The major configuration details of field devices, control strategies, and function blocks are described. Experimental results were analyzed for examining the parameter options as well as the control loop actions in response to invalid measurements to compare the safety and availability improvements between the CIH and the CIF. The proposed analysis can be useful to enable economical solutions for design phase of the FF-based control loops.
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Petri net modeling for performance analysis of FF-based process control in terms of safety and availability enhancement
(2017-12-13)
Sangsuwan, Thaksin
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Whatphat, Nopthawach
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Chanwutitum, Jirasak
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Thepmanee, Teerawat
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Julsereewong, Amphawan
In case of device and communication failures, a basic process control using Foundation Fieldbus technology can be configured to provide either safety improvement for preventing hazards or availability enhancement for minimizing production losses. The purpose of this paper is to introduce a system modeling with Petri Net technique for representing the behaviors of the proportional-integral-derivative (PID) and cascade loops with 'Control in the Field' (CIF) and 'Control in the Host' (CIH) architectures in response to instrument and communication failures. The proposed modeling is useful for performance analysis of the interested control loops in terms of safety and availability improvement. Stakeholders of both brownfield and greenfield projects in process industry sector can select a proper solution to their necessary performance requirements.
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Safety and availability of basic process control using foundation fieldbus with control in the field - An experimental analysis
(2017-08-01)
Sangsuwan, Thaksin
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Thepmanee, Teerawat
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Julsereewong, Amphawan
Detailed knowledge of how to balance between safety and availability for instruments is essential to successful design and implementation in fieldbus-based process control systems. The configuration correctness is crucial to actually obtain the benefits of digital fieldbus technology used. In actuality, a number of device parameters must be set to provide the required functionalities. This paper focuses on improving safety and availability for the proportional-integral-derivative (PID) and cascade control strategies using Foundation Fieldbus (FF) with control in the field. The aim of this paper is to analyze the logical behaviors of PID and cascade loops in two conflicting purposes for studying how different configuration options affect the interlocks between function blocks located in instruments as well as the initialization and fail-safe mechanisms in response to invalid measurements. For safety purpose, the interested control loops are configured to bring the process to a safe state in the presence of a fault. For availability purpose, the interested control loops are configured to keep the process running in the event of a failure. A water tank process is utilized as a case study for control loop implementations. Interactions between the status propagation and mode shedding for demonstrating the studied control loop behaviors are examined experimentally in Petri net models. In addition, the function block options for bumpless transfer and setpoint tracking are also described. The proved configuration method for proper operations in balancing the interests of safety and availability is proposed.
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Reliability modeling of emergency shutdown function for heat recovery steam generator control
(2016-10-01)
Chairuan, Chaichan
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Julsereewong, Amphawan
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Thepmanee, Teerawat
This paper presents a method for evaluating reliability and unreliability of emergency shutdown function for a control system of heat recovery steam generator (HRSG), which is operated with active redundant for providing safety and protection. The studied triple-pressure HRSG for driving the steam turbine in a power plant consists of three sections: high pressure section, intermediate pressure section, and low pressure section. A safety shutdown is based on level and pressure sensing system with three pressure transmitters and three level transmitters in each section for implementing a voting algorithm in order to tolerate the failure ofone sensor. Fault tree analysis (FTA) is employed as a tool for analyzing probability functions ofsuccess and failure for three possible voting algorithm configurations. Based on the obtained modeling, complex data of the studied system are transformed to accurate prediction of its reliability and unreliability.
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Potential of bacteriocin-producing lactic acid bacteria for safety improvements of traditional Thai fermented meat and human health
(2015-11-01)
Swetwiwathana, Adisorn
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Visessanguan, Wonnop
Lactic acid bacteria (LAB) are very important in converting of agricultural products into safe, delicious and shelf stable foods for human consumption. The preservative activity of LAB in foods is mainly attributed to the production of anti-microbial metabolites such as organic acids and bacteriocins which enables them to grow and control the growth of pathogens and spoilage microorganisms. Besides ensuring safety, bacteriocin-producing LAB with their probiotic potentials could also be emerging as a means to develop functional meat products with desirable health benefits. Nevertheless, to be qualified as a candidate probiotic culture, other prerequisite probiotic properties of bacteriocin-producing LAB have to be assessed according to regulatory guidelines for probiotics. Nham is an indigenous fermented sausage of Thailand that has gained popularity and acceptance among Thais. Since Nham is made from raw meat and is usually consumed without cooking, risks due to undesirable microorganisms such as Salmonella spp., Staphylococcus aureus, and Listeria monocytogenes, are frequently observed. With an ultimate goal to produce safer and healthier product, our research attempts on the development of a variety of new Nham products are discussed.
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Reserch and development of the city commuter installed ICT functions in consideration of usability
(2015-01-01)
Okumura, Kohei
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Sararuengpong, Kitipat
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Chaweechan, Charoen
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Ishida, Koji
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Ishigami, Kazuyuki
It is commonly believed that the development of ICT contributes in various fields. Accordingly, the Ministry of Internal Affairs and Communications of Japan has promoted «ICT community development business». In local area where does not have enough public transport facilities, it is hard for elderly people who cannot drive a car to go out. Additionally, it is supposed that the time national disasters like earthquakes happen all of transport would be stopped. To solve these problems is the one of the goal of the business, and we research and develop a vehicle called city commuter that has convenience ICT functions. Its design is based on three-wheeled electric bicycle. This paper shows the way we decided the design of the city commuter. After that, it explains the detail of the method to create each ICT system. At the end, it describes the conclusion and the future prospects of this study.
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Applying conceptual schema to the design of knowledge management for safety activities
(2010-12-01)
Pornphol, Putsadee
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Chittayasothorn, Suphamit
At present, both small and medium size (SME) and large industries utilize machinery and modern production facilities to gain production advantages. Facilities, environment and safety management become a serious challenge. In developing countries, many workers have minimum education backgrounds and not all of them are safety conscious. Even workers with higher education sometimes have problems dealing with advanced complex equipments. High staff changing rate is also a major cause of the challenge. Knowledge management (KM) is a supplementary solution to the challenge. This paper presents a knowledge management system for safety activities and the application of the NIAM conceptual schema model to design the repository database of the system. The application of KM for safety helps both the management and qualified staff collects and organize explicit and tacit knowledge on the safety issues so that they and less experienced workers can utilize the knowledge to create better working environment. A web-based software tool has been developed to promote two way communications that finally leads to higher safety awareness, lower-risk environment and in-time accident management.

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