Research and design of computer interlocking syste

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Research and design of railway signal computer interlocking system

Abstract: This paper introduces the control requirements and design scheme of signal computer interlocking system suitable for enterprise owned railway, and focuses on the application and implementation of fault safety principle in railway signal system

key words: railway signal fault - Safety redundancy technology combined circuit

abstract:this paper introduces the control requirement and design plan of MLS which can be the same with the enterprise railway provided for itself, how to apply and implement the fail safe theory in the railway signal system is my paper emphasis

Keywords : railway signal fail--safe redundancy link circuit

1. Introduction

with the development of railway transportation towards high density, heavy load and high speed, the existing station railway signal interlocking device has been unable to meet the higher requirements of railway signal for reliability and fault safety. In terms of technology, railway signal system has gone through two stages: mechanical interlocking and electrical interlocking (relay interlocking). At present, the vast majority of interlocking systems used in China's trunk railways or enterprise owned railways are still relay interlocking systems. In the late 1970s, the emergence of new microprocessors and the gradual improvement of fault-tolerant theory and technology encouraged people to form computer interlocking system with microcomputer as the core

however, the conventional computer control system does not have the fault safety feature, that is, it does not have the ability to distinguish whether the external input information is correct or not or to guide the system to safety in case of system failure, which is greatly limited in application. At present, most of the computer interlocking systems equipped on China's trunk railways are fault-tolerant computer signal control systems of foreign railway signal companies. The scraping is to use a metal ruler to stand at the first end of the test mold top at an approximate angle. The price is quite expensive. Therefore, in recent years, many domestic railway research institutes have taken the development of fault safe railway signal control system as their main work in the near future

2. Performance requirements analysis of railway signal computer interlocking system

2.1 The basic structure of computer interlocking system

as the comprehensive performance of computer interlocking system far exceeds that of relay interlocking system, the transformation of station interlocking system from relay device to computer interlocking system has become an irreversible trend. Specifically, the advantages of computer interlocking system are mainly manifested in timeliness, safety, reliability, maintainability and cost performance

the computer interlocking system uses the existing industrial control computer to develop a set of special hardware and software systems to realize the interlocking relationship between signals, routes and turnouts. Therefore, it is essentially an interlocking logic operation system that meets the fault safety signal principle. The role of the computer in the system is to read in the operation commands and various input information on site, Then, according to the internal state of the computer and other conditions, the logic operation is carried out, and the control information is output to the actuator after judgment, so as to realize the transformation of such a complex transfer function as multivariable digital input and multivariable digital output

2.2. The real-time performance requires that the

interlocking system must seize the opportunity to collect the changes of input variables, refresh all kinds of station information in time, and output the control commands of switches and signals in time, Moreover, the export share of control commands involving safety (dangerous side [1) to emerging countries will also be greatly increased and must be output in the form of fault safety features.

2.3. reliability and fault safety

signal interlocking system is a real-time control system, which must be highly reliable. Usually, the MTBF of relay interlocking system can reach 1.3 on the premise of preventive maintenance measures × 105h[2 (about 15 years) The new molding composite machine and fault-tolerant technology for rugged components using industrial level control calculation can fully meet and exceed this index

specifically, two main problems must be solved for the computer interlocking system

reliability and safety of information transmission in the system: since the industrial computer itself does not have fault safety characteristics, the information transmitted in the system does not have safety. Affected by various interferences, radiation and faults, information distortion is inevitable, resulting in logic operation errors and possible dangerous side output

safety of information transformation and logic operation in the system: as far as the interlocking program is concerned, no matter how strict the design and commissioning method is, it is difficult to eliminate all hidden defects, which requires the introduction of error avoidance and fault tolerance mechanisms to make the probability of output of operation results at the dangerous side of the fault meet the specified requirements

2.4. Structural modularization and standardization

the scale and operation requirements of railway stations and yards are different. Therefore, both hardware and software must have the characteristics of modular structure. Hardware modularization and software truly realize the effective separation of program and data

2.5. Economy

another important reason why the computer interlocking system replaces the relay interlocking system is to reduce the system cost. Generally speaking, the system cost is reflected in the design, production, construction, commissioning and construction costs. Therefore, the computer interlocking system must fully display its advantages in the above aspects

2. The electronic universal material experimental system and the hydraulic universal material experimental system can be used to test the steel wire rope 6 Function expansion

the old relay interlocking system can only provide basic interlocking function and operation interface. In addition, the new computer interlocking system should also have fault diagnosis and analysis, replay, remote communication and other management functions

3. Overall design scheme and key technology

based on the careful analysis of the performance characteristics of the computer interlocking system and the special requirements for fault safety, the author puts forward a system architecture suitable for the enterprise owned railway, which is actually applied to the two owned railway yards of Yangzi Petrochemical Company (the total number of turnouts is about 80 groups, belonging to a large marshalling yard). The system is named hj04a railway signal computer interlocking system, Hereinafter referred to as hj04a system

3.1. System structure and working principle

from the perspective of hj04a system architecture, it belongs to a Two-Level Distributed Control System (see Figure 2 for system structure), which breaks through the old centralized signal system mode and has the characteristics of modularization and hierarchy. Modularization refers to the main module of interlocking machine, PLC and signal combination module, etc., and layering refers to that the system has operation representation layer and connection

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