Program logicalcontrollers(PLCs) are the kernel equipment of industrial control system(ICS) as they directly monitor and control industrial processes. Recently, ICS is suffering from various cyber th
ISBN:
(纸本)9781467389808
Program logicalcontrollers(PLCs) are the kernel equipment of industrial control system(ICS) as they directly monitor and control industrial processes. Recently, ICS is suffering from various cyber th
An ordinary Petri-net (PN) based approach is proposed to design a programmable logical controller (PLC) that prevents collisions among vehicles in an automated guided vehicle (AGV) system. First, a procedure is propos...
详细信息
An ordinary Petri-net (PN) based approach is proposed to design a programmable logical controller (PLC) that prevents collisions among vehicles in an automated guided vehicle (AGV) system. First, a procedure is proposed to model an AGV system as a control-hardware PN. Second, a method is formulated to design a PN supervisor (the closed-loop PN) for collision prevention. This paper defines the line, merge, divide and intersection alignments, and then adds the transitions and arcs for these four alignments into the control-hardware PN, respectively. As a result, a closed-loop PN is obtained as the supervisor for preventing collisions among vehicles in an AGV system. Finally, a method is introduced to automatically translate a closed-loop PN into a ladder diagram by Boolean expressions. Consequently, the closed-loop PN can be implemented by a PLC. An example is used to illustrate this methodology.
The failure mechanism was postulated as a combination of the high level of loading during normal activities and a non-conforming contact mechanism between the femoral condyles and the tibial insert. The question that ...
详细信息
The failure mechanism was postulated as a combination of the high level of loading during normal activities and a non-conforming contact mechanism between the femoral condyles and the tibial insert. The question that arises is: could be this phenomenon evaluated quantitatively a priori, e.g., could be the failure due to delamination wear predicted? In order to do some finite element simulations were performed to dynamically determinate the contact area and contact pressure for three different activities. The results obtained using VIPRO platform lead to the conclusion that many clinically reported failures of the tibial tray are caused by the adhesive and fatigue wear.
An ordinary Petri-net (PN) based approach is proposed to design the programmable logical controller (PLC) for preventing collisions between vehicles in an automated guided vehicles (AGV) system. First, method is propo...
详细信息
An ordinary Petri-net (PN) based approach is proposed to design the programmable logical controller (PLC) for preventing collisions between vehicles in an automated guided vehicles (AGV) system. First, method is proposed to model an AGV system as an ordinary PN, called the plant PN. Second, for collision prevention in an AGV system, module control methods are proposed to design the PN supervisor (the closed-loop PN) by augmenting the plant PN. In detail, three modules are defined the line, divide, and merge modules, in the plant PN, and the control module methods are presented for each of these three modules. As a result, the closed-loop PN of an AGV system is obtained and can be analyzed using the PN theory. Finally, method is proposed to translate a closed-loop PN into a ladder diagram. Consequently, the PN supervisor is implemented by a PLC using these proposed methods. A laboratory AGV system is used to illustrate this approach.
In this paper, we propose a network-based remote diagnosis system for ion nitrogen furnace. This system consists of the site measurement, control and diagnosis end, GPRS communication module, and remote fault diagnosi...
详细信息
ISBN:
(纸本)9783038353140
In this paper, we propose a network-based remote diagnosis system for ion nitrogen furnace. This system consists of the site measurement, control and diagnosis end, GPRS communication module, and remote fault diagnosis end. This system can collect and transmit data for the remote fault diagnosis. Experiments demonstrate that the proposed system can satisfy the user-specified requirements.
PFC (Predictive Functional Control) is a simple but very effective SISO (Single-Input Single- Output) predictive controller which does not require any matrix inversion or numerical minimization of a cost function, the...
详细信息
PFC (Predictive Functional Control) is a simple but very effective SISO (Single-Input Single- Output) predictive controller which does not require any matrix inversion or numerical minimization of a cost function, therefore it is easy to realize in a PLCs (programmable logical controllers) or a DCS (Decentralized Control Systems). The manipulated variable and/or its increment, as well other variables can be constrained easier than when using PI(D) (Proportional, Integrating, and Derivating) controller. Furthermore PFC handles the dead time process better than with PI(D) controller. Three industrial applications of PFC for two distillation columns and a reactor in a petro-chemical plant were implemented and the experiences are presented here.
A new visual monitoring communication algorithm model is described in this paper which can improve the communication efficiency between the PLC(programmable logic controller) and its programming software. The model co...
详细信息
ISBN:
(纸本)9781784660468
A new visual monitoring communication algorithm model is described in this paper which can improve the communication efficiency between the PLC(programmable logic controller) and its programming software. The model consists of dynamic packaging algorithm and scrolling view algorithm aiming at meeting real-time visual monitoring. It is described in detail that how to adjust the length of communication data frame and refresh the data of current scrolling view of the programming software concerning the algorithm model. The experimental results show that the communication efficiency and the interface refreshing properties of visual monitoring will be improved with the increase of communication traffic load which proves that the algorithm modelling is effective.
This paper deals with problems of using an autonomous system for measuring temperature profiles inside boreholes. This system is a practical result of integrating various available approaches (i. e., using digital sen...
详细信息
This paper deals with problems of using an autonomous system for measuring temperature profiles inside boreholes. This system is a practical result of integrating various available approaches (i. e., using digital sensors of Dallas DS18B20 and analogue sensors of Pt1000, communication interfaces/buses of RS-232 and 1-Wire, a programmable logical controller of B&R X20 CP1484, and own developed software applications) into a compact measurement device. During our thermal response test (TRT) experiments, measurement of the temperature profiles is now an integral part of them, so the developed device must be not only quite simple, but also robust. This paper also includes summarizing existing practical experiences in the field of temperature profiles – measurement technology, data acquisition, data analysis, data presentation, and their role in connection with realizing the TRT experiments.
The article analyses the automatic control systems in modern wood drying facilities as well as their functions and possibilities. The analysis of the publications available [1, 2, 3] indicates that nowadays there are ...
详细信息
ISBN:
(纸本)9781634398015
The article analyses the automatic control systems in modern wood drying facilities as well as their functions and possibilities. The analysis of the publications available [1, 2, 3] indicates that nowadays there are widely applied in our country various types of wood drying facilities with different level of automation. Although the possibilities of the fully computer-assisted control systems at the wood drying facilities are considered to be rather extensive, but in the scientific publications available there has been noticed the shortage regarding the information on the structure of the systems, the algorithm concerning the manufacturing processes, programs, sensors and their interrelation and correlation.
It becomes a tendency that the application of copper pipe and aluminum pipe welding joints in the field of refrigeration. Based on analysis of Cu-Al pipe welding process, a PLC automatic control system was developed t...
详细信息
It becomes a tendency that the application of copper pipe and aluminum pipe welding joints in the field of refrigeration. Based on analysis of Cu-Al pipe welding process, a PLC automatic control system was developed to accurately control the resistance welding machine. The executive mechanism is composed of pneumatic components and controlled by the PLC system to complete the Cu-Al pipe welding process. Under the PLC control, the welding time parameter can be changed, according to the pip size. And the time error of the control system is limited in 0.01s. When the coil temperature rises up to 90 degrees C or the network voltage fluctuates more than +/-10%, the control system alarms the operator and the welding process can not be started. (C) 2011 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of [CEIS 2011]
暂无评论