Reliability Analysis of Safety Grade Programmable Logic Controller
This paper focuses on the random hardware failures necessary for the safety assessment of the reactor protection system (RPS). A prediction method of the hardware failure rate for safety assessment is suggested, and applied to the safety grade programmable logic controller (PLC) to identify design weak points from a safety point of view
Overlay Architecture for Field Computing Systems
Conventional production systems have mainly focused on production practices. Future production system is required to have more flexibility to deal with various problems for production auxiliary tasks in addition to production practices. In order to solve these problems, the use of field data from devices on the factory floor is required in many cases. For using the field data more effectively for auxiliary tasks, an approach to add functions to field devices is increasingly required. However, for building a computing environment that achieves this approach, it is necessary to solve the following two issues. (1) Provide field devices with the common computing environment independent of the device type. However, this environment should not adversely affect the original device functions for production practices. (2) Allow multiple persons in charge of auxiliary tasks to use the common computing environment concurrently. In other words, persons in charge can select necessary devices and build distributed applications on top of them without interfering with other activities. This paper presents FOA (field overlay architecture) that allows building the computing environment on top of the production system to deal with various problems for production auxiliary tasks, and also describes a new operating model of FOA-based production system
Accurate measurements of output characteristics and detonations of motorbike high-speed racing engine and their optimization at actual atmospheric conditions and combusted mixture composition
Abstract At a motorbike high speed racing engine there is very important an output engine characteristics which depends significantly on a detonation combustion rate, atmospheric conditions and a combusted mixture composition. The combustion process has got a relevant influence on a wear degree of main engine parts or on their damage eventually. The detonation combustion rate is very important because this kind of burning can be not only destructive but a useful phenomenon, as well. If the process of detonation burning is kept on a certain level, it can help significantly to the next increasing of an engine power output. In this article there is described the measurements of output characteristics of a high-speed racing engine which were performed by means of a data-recording system and the detonation combustion was evaluated using a quantitative method. The actual values of atmospheric conditions and the mixture composition were added to the measured values. Then the obtained values are compared visually with a damage degree of an engine piston caused by the detonation burning. The result is a limit value expressed in a number of detonation units related to a run distance interval of the vehicle driven by the high-speed racing engine. In framework of this run distance interval there is the process of detonation burning profitable. As well as it increases an engine power output and together it is not destructive with regard to engine design parts.