Computer interlocking graduation thesis 1
Discussion on common faults and treatment methods of computer interlocking system
Computer interlocking system is the guarantee system of railway traffic safety technology, which is of great significance to ensure the reliable, long-term and stable transportation production in security team. This paper introduces the common faults and their treatment methods from four aspects: computer unit fault, communication line fault, switching fault and power supply guarantee.
Computer interlocking; Fault; job operation
With the rapid development of modern railway, computer interlocking system gradually replaces electric interlocking system. How to ensure the safe, reliable and long-term stable operation of computer interlocking system and how to maintain and deal with faults in time is of great significance to railway transportation and traffic safety. From the maintenance point of view, this paper puts forward some reference opinions on the fault treatment and maintenance of computer interlocking, and introduces the fault types and treatment principles of computer interlocking equipment, common faults and treatment, as well as specific computer unit faults, communication line faults, switching faults, power supply faults, etc.
1. Computer interlocking equipment fault handling steps
After receiving the failure notice of computer interlocking equipment, it is forbidden to move the equipment blindly.
First of all, we should grasp the fault phenomenon, the influence scope and the influence degree on vehicle service, analyze the interlocking relationship and rule out the possibility of misoperation of vehicle service.
Then check the running status of interlocking machine, console (display) and control display machine (upper computer) in the computer room, check whether the information indicator lights on the acquisition board and driving board of interlocking machine are normal, then preliminarily grasp the information, then decide how to deal with it, and report the situation to the section scheduling and workshop in time.
Then, according to the fault phenomenon, the location of the fault is preliminarily analyzed, and the indoor fault or outdoor fault is distinguished, and the interlock machine, control display machine fault or relay partial fault is distinguished. If the fault cannot be identified immediately, simple faults, such as turnout and red light belt, etc. It can be skipped and handled like a common fault, and judged and handled with the help of console ammeter, track test board, microcomputer monitoring and other equipment.
2. Fault types and treatment principles of computer interlocking equipment
2. 1 fault type
The faults of computer interlocking system can be divided into hardware faults and software faults according to their nature. According to the time characteristics of hardware failure, it can be divided into permanent failure # intermittent failure and instantaneous failure. Once a permanent hardware failure occurs, it will exist forever. Before troubleshooting, the faulty equipment cannot resume normal operation. Permanent hardware failure is usually caused by component failure, disconnection or short circuit of connecting wires, etc.
Intermittent faults are repeated faults, which can be eliminated automatically without elimination. They are usually caused by component performance changes, poor connector contact and solder joint virtual connection. Transient faults are usually accidental events caused by external interference factors. Software fault is caused by defects in software design, which is exposed under specific station conditions and special operation combinations.
2.2 handling principles
For the treatment of permanent faults and intermittent faults, firstly, the standby equipment is used to replace the faulty equipment, so that the faulty equipment is out of operation and the system returns to normal. Then analyze the fault phenomenon, check the faulty equipment, find out the cause of the fault, and solve it by replacing the circuit board or eliminating the fault point. If it is difficult to find out the reason in a short period of time, the system should be reset first to restore the system operation, and then the environment, signal equipment and console operation before and after the failure should be thoroughly investigated and recorded in detail, and the regular situation should be found out in combination with the previous records of fault handling. Attention should be paid to the analysis of environmental conditions such as temperature, power supply, grounding state and weather conditions of the computer room, so as to improve environmental conditions and prevent failures. The software running in the field is usually stored in a solidified way, and the field personnel have no methods and means to view and modify the program. The design unit is responsible for the lifelong maintenance of the software. The target program code executed in the computer is extremely readable and logical, and an instruction or a code error may cause the system to crash. Therefore, strict protective measures must be taken. Software defects will exist forever if they are not eliminated, and faults can reappear under the same conditions. Regularity factors can be found from repetition and provided to design units, which will improve software design and eliminate errors in programs.
3. Common faults and treatment methods
Computer interlocking system is a distributed system composed of multiple microcomputers. Each microcomputer is composed of a plurality of circuit boards, and the microcomputers are interconnected through a network to exchange information. In response to the first operation, many components are needed to complete the first control function, so the failure of a function may be caused by many different reasons of different components in the system. The faults of different components have different influence ranges on the system functions, and the probability of multiple faults of 1 or above occurring in the system at the same time is extremely small. After the fault location is determined, the main and standby systems should be switched to restore the system operation as soon as possible to reduce the impact on transportation, and then the fault part should be stopped for maintenance and troubleshooting. The following are common faults and solutions.
3. 1 Computer unit fault and its treatment method
(1) Interlocking machine: STD board failure, which is embodied in that the running light on STD floor stops flashing, the receiving light and the interrupt light go out, the indicator lights on acquisition floor and driving floor stop flashing, and the failure indication is CPU board failure.
Treatment method: replace the CPU board; STD layer interrupt 2 lights go out, flashing lights run, but some lights go out when receiving and sending lights flash. Replace STD-0 1 board (communicating with monitoring machine and interlocking machine) according to the position where the light goes out. BJ-A0 board failed, STD running light, interrupt light and alarm light did not flash, and the acquisition work light was normal. Solution: Replace BJ board or fasten socket.
(2) Monitor: PC-0 1 network card is out of order, and the transceiver lights on STD layer 1 group of its interlocking machine are not flashing normally, while other lights are normal. Interlock and interrupt communication? Tips; When the Ethernet card fails, the communication between the monitoring machine and the maintenance machine is interrupted. When the VGA graphics card fails, the display screen does not display or the graphics are defective.
Solution: Replace the PC-0 1 network card to return to normal. The graphics card needs to be replaced or the plug-in is not strong.
3.2 Communication Line Faults and Handling Methods
The bus plug is loose or poorly plugged, so the interlocking machine cannot communicate with the monitoring machine. However, the LS plug is loose or not properly inserted, and the working machine and standby machine of the interlocking machine cannot be synchronized.
Solution: Check whether the plug is loose. Only when the contact is completely good can you synchronize by pressing the online button.
3.3 Switching failure and handling methods
When the switch board of the zero floor of the interlocking machine fails, the switching inspection gives an error, and the communication between the monitor and the interlocking machine is interrupted. The above faults are eliminated. The failure of the switch board of the console display and digitizer will cause the console display and digitizer to be unable to switch to the working display with the switch of the display, and may also cause the display to be non-displayed.
Solution: At this time, to eliminate the influence of external power factors, it is necessary to replace the switch board and troubleshoot.
3.4 Power failure and treatment methods
The failure of dynamic regulated power supply will lead to the failure of all dynamic relays and the inability to drive outdoor equipment. After the computer is powered off, UPS is powered off, STD is powered off, acquisition is powered off, drive is powered off, and display is powered off, all loads cannot be turned on.
Solution: Check the working condition of the input power supply. If the output power supply works normally, it is necessary to replace the power board according to the fault point to restore the fault phenomenon.
4. Concluding remarks
No matter how the fault causes and fault phenomena change, as a qualified interlocking system maintenance worker, as long as he seriously summarizes the fault phenomena encountered in his usual work, insists on continuous learning and is familiar with the working performance of the equipment, he can accurately judge the fault, maintain the computer interlocking system and ensure the safety of railway transportation and the normal operation of the equipment.
Computer interlocking graduation thesis II
Discussion on the transformation scheme of computer interlocking system
The safety of railway transportation is becoming more and more important. The original railway computer signal interlocking device can no longer adapt to the development of the present form, so it is necessary to effectively transform the computer interlocking system. This paper first analyzes the performance requirements of railway signal computer interlocking system, and then introduces the equipment layout and computer room conditions of computer interlocking system. At the same time, combined with the engineering example, the reform of computer interlocking system is deeply discussed, and my own suggestions and opinions are put forward, which has certain reference value.
Keywords: computer; Interlocking system; modification works
I. Introduction
With the rapid development of China's railway transportation, China's railway mileage has ranked first in the world, and it is developing in the direction of high speed, heavy load and high density. Therefore, the safety of railway transportation is becoming more and more important. The original railway computer signal interlocking device can no longer meet the current development, so it is necessary to effectively transform the computer interlocking system.
Second, the railway signal computer interlocking system performance requirements analysis
With the advantages of computer interlocking system becoming more and more obvious, the relay interlocking system widely used in the past has lagged far behind the comprehensive performance of computer interlocking system, so it is undoubtedly an inevitable trend for railway signals to develop into computer interlocking system. The performance requirements of railway signal computer interlocking system mainly include the following aspects: high cost performance, safety, reliability, timeliness and maintainability.
(a) real-time requirements
Computer interlocking system must output signals, switches and other control commands in time. By collecting the changes of input variables, we can refresh all kinds of station representation information in time and output it in a safer form.
(2) Economy
An important reason of computer interlocking system is its economy, which is also the reason why it can replace relay interlocking system. Computer interlocking system can effectively reduce the cost of construction, debugging, design, construction and production.
Modularization and standardization of structure
Because each railway station is large and small, and its operation requirements and scale are different, the software and hardware of computer interlocking system must have modular structural characteristics, which can effectively separate data and truly realize programming.
(D) Functional expansion
Generally speaking, the relay interlocking system used in the past can only provide users with basic operation interface and interlocking function, and there is no other follow-up function, while the computer interlocking system does not. In addition to the above characteristics, it also has management functions such as remote communication, fault analysis, fault diagnosis and fault recurrence.
Three, computer interlocking system equipment layout and room conditions
The microcomputer equipment of this system is installed in three 19 inch standard cabinets. These three cabinets are interlocking cabinet A, interlocking cabinet B and monitoring cabinet respectively.
Cabinet size: length? Wide? Height =600? 750? 1800mm. The occupied machine room area is not less than15m2. Anti-static floor is set indoors. Doors and windows are dustproof. Air conditioning, indoor temperature should not exceed 25℃ in summer. The operating room is equipped with a driving console and a graphic display. Install relay combination frame and power supply screen in mechanical room. The environmental conditions of the machine room and operation room are the same as those of the relay interlocking machine room and operation room.
The microcomputer equipment of this system adopts AC 220V power supply. The voltage value is 220V? 10%。 The total capacity does not exceed 2 kva. The single power supply is led out from the signal power supply panel. Two sets of 1.4KVA UPS are used, and 2.0KVA UPS is used in the big station. One working machine supplies power to all equipment, and the other is standby. Under the control of the power control box, two UPS can be switched automatically or manually. You can also supply power directly without UPS.
I/O interface adopts DC 24V power supply. Voltage range 24V? 10%。 It is powered by DC 24V power output from signal power board. When the dynamic board is used, another local power supply with 30V voltage is needed.
The system requires a separate grounding wire for the microcomputer system, and the grounding resistance should be less than 4 ohms. The distance between the buried ground and other grounding wires shall not be less than 20m. This line should not overlap any other equipment.
Fourth, the transformation of computer interlocking system
(1) Project Overview
In 2002, the Italian ANsALD0 computer interlocking system of Bajin Line was replaced by JD-I A computer interlocking system of North Jiaotong University. The outdoor equipment is not moving, the indoor combined rack equipment is reformed, and the computer and its I/O interface are replaced with new equipment.
(2) Construction survey
Before the formal transformation, it is necessary to master the use and working principle of the old equipment in the original computer interlocking system, so that the physical objects and drawings can be combined and correspond to each other; Take effective protection measures for those old equipment that are prone to traffic accidents and problems in construction projects; The purpose of this is to avoid sudden failure.
(3) architecture
The reconstruction and construction of computer interlocking system mainly includes the construction on the day of opening and the construction before opening.
(1) It is impossible to directly build the computer equipment of the old system, because many relays were fixed on the computer equipment and were in operation before they were dismantled. Therefore, it is precisely because of this that an interface cabinet is specially added in the reconstruction project of computer interlocking system. The new interface cabinet introduces spare contacts and relay contacts, while the old contacts that the relay is using do not touch them.
(2) Effectively assemble the wiring of relay coil, mainly from computer interlocking drive to interface cabinet. Because these relays are all working before switching on, in order to avoid the problem of wire mixing, this part of the wiring can not be directly connected to the coil, but can only be temporarily distributed to the side terminals.
(3) In the JD-IA computer interlocking system used in the past, the circuit combining the directional circuit with the system is complicated, and there are many places that need to be reformed. Therefore, in the whole transformation process, we temporarily stopped using it and closed the circuit combining the directional circuit with the system.
(4) All cables between the computer lightning protection cabinet and the interface cabinet should be constructed in advance, mainly including public loop cables, driving cables and collecting cables.
(5) All kinds of wiring related to microcomputer monitoring must be done in advance, and protection units and isolation sensors should be installed nearby. The monitoring contents that can be involved in microcomputer monitoring include: main filament broken alarm circuit, coded current, cable insulation, coded voltage, received voltage/interval frequency shift transmission, switching current, track voltage, output/input voltage of power board, etc.
(6) Do a good job in the overall construction of equipment protection grounding wire and lightning protection grounding wire in computer interlocking system. This is because computer communication, sampling and other equipment belong to high-frequency equipment, and these high-frequency equipment are prone to generate strong induced voltage. If it is not controlled, the consequences will be unimaginable. Personal protective ground wire must be 1500mm copper plate? l000mm？ L0mm, the cross section of the lead-out wire shall not be in the same groove or ditch as the grounding wire of other equipment, the area shall not be less than 40 square centimeters, and the grounding resistance shall not be greater than 4 ohms. Compared with personal protective grounding wire, lightning protection grounding wire is less dangerous, so ordinary graphite grounding wire can be used. In the process of construction, in order to avoid other equipment, PVC pipe can be used to protect lightning protection grounding wire, and the resistance to ground should not be greater than 8Q.
(7) Improve the construction of new power circuits. These new power supplies mainly refer to KF and KZ power supplies in relay cabinet and interface cabinet of repeater newly added in computer interlocking system. Point? Architecture. For the repeater relay combination cabinet, external wiring is required. Point? During construction, the internal wiring can be constructed in advance.
(8) After completing the first seven construction steps, the relay wiring can be changed in time during the opening process, and attention should be paid to the computer drive. The purpose of this is to minimize the impact of the transformation on the application.
(D) The transformation process of introducing computer interlocking teaching and training system.
In practice, we often find that after computer interlocking equipment is put into use, electrical maintenance personnel are not familiar with computer interlocking equipment, which leads to inadequate maintenance and long delay after failure, which affects driving; Due to improper operation of computer interlocking equipment department, train operators have mastered things that should not affect train operation, which has brought serious interference to railway transportation and posed a serious threat to railway transportation safety. In order to avoid the recurrence of this problem, we introduced the computer interlocking teaching and training system in the transformation process. The teaching and training system can simulate on-site computer interlocking equipment and realize the consistency of computer interlocking equipment operation, computer network and computer software. Using this teaching and training system to train electric and vehicle operators can greatly improve the technical level of on-site maintenance personnel and users.
The application of computer interlocking teaching and training system is of great significance for learning, familiarizing with computer interlocking equipment and operating procedures, analyzing and finding computer interlocking equipment faults, and effectively preventing and reducing the fault delay caused by users' unfamiliarity with equipment and operating functions. The teaching and training system can be used in the telecommunications sector to analyze unexplained failures, prevent the recurrence of similar signal failures, play an active preventive role in reducing computer interlocking equipment failures, improve the overall level of safe use of railway equipment, improve the overall business level of telecom maintenance personnel and station attendants, and ensure the safety of railway transportation. It has good economic and social benefits and prospects for popularization and application.
(V) The use effect after the transformation
The reformed computer interlocking system adopts highly reliable industrial control microcomputer and uses network communication technology to form a multi-computer distributed control system. Interlocking subsystem adopts dynamic redundant dual-machine hot standby structure, which has the functions of automatic fault switching and manual switching, and meets the requirements of high availability of the system. Interlocking software adopts double coding, modularization and structural design. Standardization of programming. The safety output is driven dynamically. The indication information is input in a dynamic coding mode, which meets the fault-oriented safety requirements. The control and display subsystem adopts dual-machine hot standby structure, and the control and display machine conversion box is used for manual switching to meet the requirements of high availability of the system. Man-machine interface has many optional operation methods and manifestations. You can select the operation method from the button panel, digitizer or mouse. The station display device can be selected from a graphic display (CRT) or a light strip display panel. The system has perfect self-checking and fault diagnosis functions, and can provide remote monitoring, providing strong technical support for equipment maintenance. The system has the ability to exchange information with other information systems.
References:
Wang Yongxin. Automatic control of station signals [M]. Beijing: China Railway Publishing House, 2002.
China Railway Communication Signal Company. Technical Manual of Railway Engineering Construction: Signal [M]. Beijing: China Railway Publishing House, 1996.
[3] Meng. Computer interlocking information management system [D]. Research Institute of Ministry of Railways, 2000
[4] Zhu Geng Research on fault model establishment and fault diagnosis method of railway signal computer interlocking system [D]. Hefei University of Technology, 2003
[5] Tang Tiantian. Research on the application of reliability design method of computer interlocking system software [D]. Hefei University of Technology, 2004
Wang Feng. Discussion on some technologies of railway station computer interlocking system [D]. Nanjing University of Technology, 2005
[7] Li Xi, Wei Zhen, Yang Lu. Research on centralized communication protocol for enterprise railway dispatching [a]. Proceedings of the 13th National Symposium on Automation Application Technology in 2008 [C].2008
Computer interlocking graduation thesis 3
Discussion on testing method of computer interlocking software
Abstract: Safety is the eternal theme of railway transportation production. Interlocking software is the key software to ensure the safety of trains or locomotives in railway stations, and efficient and sufficient testing plays an important role in ensuring its safety. This paper describes the architecture of the interlocking system under test and the design of the automatic test system. The structure test and function test of computer interlocking software are completed by using white box method and black box method, and the structure test example and black box test block diagram are given.
Keywords: software testing; White box method; Black box method
1, Automatic Test Method for Interlocking Software
The basic structure of 1 1 interlocking software
The content of this paper is mainly the routing control module of pin lock operation layer (see figure 1). The main functions of this module are:
1) route establishment;
2) Check the consistency of line selection;
3) route locking;
4) the signal is open;
5) Keep the signal unblocked;
6) Route unlocking is normal;
7) The abnormal route is unlocked;
8) Switch sheet operation.
White-box test of 1 2 interlocking software
As a structural testing method, white-box testing is also called structural testing, logic-driven testing or program-based testing. Using this testing method, testers can see the tested source program, analyze the internal structure of the program, and design test cases according to the internal structure. White-box testing fully understands the internal logical structure of the program and tests all logical paths. This is a detailed path test. When using this scheme, testers must check the internal structure of the program and obtain test data from the logic of the program.
Its main advantages are:
(1) can test the coverage of specific parts inside the program;
② The following types of errors can be found: the internal control structure of the program is incorrect and the internal data structure of the program is incorrect.
The main disadvantages of white box testing are:
(1) only pays attention to the internal structure of the program, and it is impossible to detect the functions that have been clearly defined in the software requirements specification but omitted in the software implementation;
② Unable to check the external features of the program.
Whether each path in the white-box test program runs correctly according to the predetermined results. This paper takes the route search process in route establishment as an example to illustrate.
1.2. 1 test case design
The normal exit path is AB-DG, and the abnormal exit path is ABCEH. The other three paths are intermediate results. Therefore, in the design of test cases, it is enough to cover these five paths and supervise the input parameters, intermediate results and output results.
Black box test of 1 3 interlocking software
Black-box testing is usually used for functional testing, black-box testing or specification-based testing. When testing in this way, the program under test is regarded as a black box that cannot be opened, and its internal structure cannot be understood. Regardless of the internal structure and characteristics of the program, the tester only knows that the input-output relationship of the program or the function of the program conforms to a certain functional relationship. It must rely on the requirement specification that can reflect this relationship and program function to consider and determine the test cases, and infer the correctness of the test results, that is, it can only be based on the external characteristics of the program. Black-box testing method can be tested from the standpoint of users, and it is easy to find the following types of errors: incorrect or missing functions, interface errors, data structure or external database access errors, performance errors, initialization and termination errors, etc.
However, the black-box testing method has the following main shortcomings: ① It depends on the correctness of the software requirements specification. But we can't guarantee that the software requirement specification is completely correct. For example, specifying redundant functions in the software requirements specification or omitting some functions is totally powerless for black-box testing. (2) can't test the specific part of the program. The block diagram of automatic black box test for interlocking software is shown in Figure 4. In this system, the interlocking software under test runs in its own host environment, and the whole system under test is connected to the test platform through the network interface. The test platform consists of test software system and station signal equipment simulation system. The test software system consists of a test case database, a running result record database, an analysis and judgment module and a network communication module, as shown in Figure 5.
Working principle:
1) Automatically generates a test command queue according to the specified station signal plan (data file).
2) The test case database outputs the simulated operation command to the tested interlocking software and sends it to the operation result recording database for recording. After the operation result record database also receives the output driving command of the tested interlocking software and the state information of the station signal equipment simulation system, the analysis and judgment module compares the pre-stored results with the input results. If they are consistent, the next simulation operation command is output. If not, the analysis and judgment module designs a new simulation test command according to the fault phenomenon and retest. If there are three failures, the analysis and judgment module will not design a new test command, but return to the original test command queue to continue execution. All consistent results will be deleted from the running result record database, while inconsistent results will be recorded.
3) Set the equipment status module, which can inject faults into the designated signal equipment, simulate various abnormal state transitions, and achieve the purpose of safety testing under fault conditions.
2. Safety test of interlocking software
Interlocking software can not only complete the interlocking control function that interlocking software should complete under normal input conditions, but also contain basic safety requirements.
1) The software system of computer interlocking must meet the reliability and safety requirements of software standard detection.
2) The safety improvement grade of computer interlocking software should be divided into four grades, from high to low, which are 4~ 1 respectively. Classification is equivalent to the provisions of EN50 128 (railway control and protection system software) and EN50 129 (railway safety electronic system).
3. Conclusion
The purpose of software testing is to find out as many errors as possible, but it involves how to design test cases reasonably. The system uses path coverage method in white box test, equivalence class division method in black box test and FTA technology in security test. Only when the software is fully and reasonably tested can the interlocking software achieve higher reliability and safety and truly serve the society.
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