Railway large-scale road maintenance machinery electrical control system based on PPC, PLC and field bus

PLC (Programmable Logic Controller), referred to as programmable controller, is a new type of industrial control device based on microprocessor, integrated computer technology, communication technology and automatic control technology. It came out in the 1960s and still maintains a strong momentum of development. It has the advantages of small size, rich functions, flexible configuration, adapt to harsh environment, strong anti-interference, high reliability, convenient programming and low price. It is widely used in various industrial processes such as electric power, machinery, metallurgy, chemical industry and textile industry. Controlled. It can not only replace the traditional relay control system, but also constitute a complex process control network.

Fieldbus technology was developed in the late 1980s. It is a hot spot in the field of automation. It is the development direction of the new generation of control systems. It integrates digital communication technology, computer technology, automatic control technology, network technology and intelligence. Various technical means such as instruments have fundamentally broken through the limitations of traditional "point-to-point" analog signals or digital-analog signal control, forming a fully distributed, fully digital, multi-variable, multi-node communication and control system. . The fieldbus is a digital, two-way transmission, multi-branch communication network connecting field smart devices and automation control devices, based on digital intelligent field devices. Digital intelligent field devices dispersed in various sites are connected by field bus and connected to the control room

The controller and monitor together form the Fieldbus Control System (FCS).

The fieldbus technology actually uses the serial data transmission and connection method to replace the traditional parallel signal transmission and connection method. It sequentially realizes the data transmission between the control layer and the fieldbus device layer, while ensuring the real-time transmission. Realize the reliability and openness of information in the case. The general field bus has the following characteristics: (1) simple wiring; (2) openness; (3) real-time; (4) reliability; (5) efficient diagnosis; (6) hardware flexibility.

At present, there are many kinds of field buses in the world, and unified international standards have not yet been established. Among them, there are strong strengths and influences: FF (Foundation Fieldbus Foundation Bus), HART (Highway Addressable Remote Transducer), CAN (Controller Area Network), Profibus (Process Field Bus), INTERBUS, LonWorks (Local Operating Network), WorldFIP, MODBus, DeviceNet, ControlNet, ASi (Actuator Sensor Interface Sensor Interface).

Electrical control systems based on PPC industrial computers, PLCs and fieldbuses have been obtained in the field of industrial automation such as metallurgy, electric power, petrochemicals, mining, cement, water treatment, dairy beverages, beer canning, tobacco processing, mechanical assembly, product packaging, etc. Widely used, but not widely used in the electrical control system of railway large-scale road maintenance machinery. According to the characteristics of railway large-scale road maintenance machinery control system, this paper proposes a design scheme of railway large-scale road maintenance machinery electrical control system based on PPC industrial computer, PLC and INTERBUS field bus.

2 status

Road maintenance mechanization is an important technical means to realize the modernization of railway maintenance and maintenance, and to ensure uninterrupted railway transportation and driving safety. In order to meet the technical development requirements of rapid and heavy railways and heavy rail structure, railways in developed countries have adopted large-scale road maintenance machinery for railway line maintenance. By the end of the 1980s, the pattern of large-scale road maintenance machinery was basically formed. . At this time, China still relies on manual, small machinery and non-standard self-made equipment for line maintenance, poor quality and low efficiency, especially in busy trunk lines, and the contradiction between line maintenance and operation is particularly prominent.

In the early 1980s, China introduced advanced large-scale road maintenance machinery manufacturing technology from the Austrian Plasser-Taylor Company, and established the development of large-scale road maintenance machinery to adopt “technical introduction—digestion, absorption—localized production—development and innovation. "The way." Through more than 20 years of imported technology and localized production, we have learned the advanced technology of foreign large-scale road maintenance machinery, updated the traditional design concept, broadened the development ideas, and enhanced the ability to develop products with independent intellectual property rights.

With the leaping development of the railway and the intensification of market competition, accelerate the process of introducing, digesting and absorbing foreign advanced technologies for large-scale road maintenance machinery, speed up research and development of products with independent intellectual property rights, speed up the development of new products, develop core technologies, and innovate and Beyond has become the top priority of the current work, and it is urgent.

Railway large-scale road maintenance machinery is a railway-specific machinery integrating mechanical, hydraulic, pneumatic, electrical, computer, laser and other technologies. According to the function, there are the following series: cleaning machine, tamping car, matching car, stabilizing car, rail grinding car, rail inspection vehicle, track inspection vehicle, trolley car, welding rail car, switch shop and so on. For the electrical control system of railway large-scale road maintenance machinery with different functions, the essential difference lies in the operation monitoring control system. So far, the technology of China's large-scale road maintenance machinery such as cleaning machine, tamping machine, smashing car and stabilizing car is mainly based on the introduction, digestion and absorption of the large-scale road maintenance machinery technology of the Austrian Plasser-Tayier railway. Developed, it belongs to the analog centralized control system, which is mainly composed of the following subsystems:

(1) vehicle power subsystem; (2) diesel engine monitoring and control subsystem; (3) high-speed running monitoring and control subsystem; (4) operation monitoring and control subsystem; (5) auxiliary equipment subsystem: including lighting, communication, Heating and air conditioning.

Among them, the operation monitoring control subsystem is the core of various railway large-scale road maintenance machinery electrical control systems, which completes the monitoring of the state of the operating mechanism and completes the control of the operation of the operating mechanism. The complexity of the operation monitoring and control system of railway large-scale road maintenance machines with different functions is very different. Such as the cleaning machine and the matching vehicle, its operation monitoring control system is relatively simple. The tamping car, the stabilizing car, the rail grinding car, the rail detecting vehicle, the track detecting car, the line car, etc., their operation monitoring and control subsystem is more complicated. The following is an example of the operation monitoring and control subsystem of the stable car. It consists of the following parts:

(1) Computer control part: It consists of the upper computer control board, keyboard and display; (2) Program control part: It consists of the microcomputer system consisting of the lower computer control board, I/O board and power output board; (3) Analog quantity Control unit: It consists of A/D converter board, D/A converter board, frequency measurement board, and analog control board of various functions; (4) Measurement part: left and right flat level sensor, acceleration sensor, vibration frequency sensor, etc. Composition; (5) Track parameter recording part: consists of recorder, front and rear electronic pendulum, positive vector sensor, measuring wheel and so on.

The characteristics of the Plass-Taylor simulation centralized control system are as follows:

(1) The monitoring part of each subsystem uses analog instruments or digital displays or indications and warning lights; (2) complex functions

The control part of the model operation monitoring control subsystem uses a plug-in analog circuit board and a microcomputer system composed of a plug-in circuit board; (3) the wiring mode of each I/O signal in the operation monitoring control subsystem is " Terminal (switch, sensor / solenoid valve, relay) - operation main control cabinet" or "terminal components (switch, sensor / solenoid valve, relay) - intermediate transition box - multi-core cable - operation main control cabinet" traditional wiring ( Figure 1); (4) The track parameter recording system is a stand-alone system with no communication and data exchange with the microcomputer and computer system.


Figure 1: Traditional wiring

Plasser-Taylor's analog centralized control system has the following deficiencies:

(1) The monitoring instrument, indication and warning lamp installation position is dispersed; the analog instrument signal is only used for display and does not enter the process control; (2) The anti-vibration performance, impact resistance and dustproof performance of the plug-in board are not good. The adjustment of the analog circuit board (such as calibration “0”, calibration) is completed by multiple potentiometers, which is more complicated; the analog system uses analog quantity to convert and transmit the transmission and control signals, and its accuracy is poor and affected by the interference signal. Large, so the control effect and system stability of the entire control system are poor; (3) centralized control mode makes the main control cabinet larger; I/O signal traditional wiring, so that there is a large number of connections in the main control cabinet Cables increase breakpoints and joints and increase the point of failure, complicating service and maintenance.

3 system requirements

In view of the deficiencies listed above, it is necessary to design a new electrical control system that meets the following requirements.

3.1 Basic requirements

The new large-scale road maintenance machinery electrical control system should have a unified display, indication and alarm, with process control function; with high reliability and stability, with good anti-vibration performance, impact resistance, dustproof performance, Experience high temperature, high humidity environment.

3.2 Specific requirements

The new railway large-scale road maintenance machinery electrical control system is mainly designed for the diesel engine monitoring and control subsystem, high-speed running monitoring and control subsystem, and operation monitoring and control subsystem. For the vehicle power subsystem and auxiliary equipment subsystem, they are point-to-point. Simple control, no redesign. The various input and output signals of these three subsystems are described in detail below.

3.2.1 Diesel engine monitoring and control subsystem

3.2.1.1 Diesel engine monitoring section

Input DI signal: oil pressure switch signal, cylinder head temperature (water temperature) switch signal, air filter switch signal, DC generator power generation status switch signal, etc.; input AI signal: speed sensor signal, oil pressure sensor signal, cylinder head temperature (water temperature) sensor signal, battery voltage signal, diesel oil level sensor signal, etc.; output DO signal: preheating indication signal, etc.;

3.2.1.2 Diesel engine control section

Input DI signal: idle speed sensing switch signal, high speed running position sensing switch signal, working position sensing switch signal, etc.

Output DO signal: throttle motor drive signal, etc.;

3.2.2 High-speed running monitoring and control subsystem (hydrostatic transmission mode)

3.2.2.1 High-speed running monitoring section

Input DI signal: each axis hanging, off the sensing switch signal, etc.; input AI signal: speed - mileage sensor signal;

Customized Cleaning Machine

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