At present, the coal mine well into the prevailing difficulties in personnel management, management of staff it is difficult to grasp the dynamics of underground distribution and operations, once the accident occurred on the mine rescue personnel lack of reliable information, emergency rescue and disaster relief, security, low efficiency of the ambulance. The introduction and use of coal mine staff positioning system, the staff to wear an electronic tag through the underground control center to monitor the nodes send their location information, real-time to master each person in the underground track of the location and activities of coal mine safety in production will have a positive role, to a certain extent reduce casualties. Normally, upload location information can also be used for staff attendance records.
1 radio frequency identification technology
111 Radio Frequency Identification development
RFID is the rise of the 20th century, 90's a new type of non-contact automatic identification technology, which uses two-way wireless data communication means, thus automatic identification and exchange of information purposes. In recent years, automatic identification technology is a rapid popularization and promotion of a variety of automatic identification method: bar code is a widely used, low-cost automatic identification operation, but a small bar code information can not be rewritten; have contact IC card row electronic data carriers the most common structure, but in many cases, mechanical contacts access is unreliable; RF ID so that items can achieve true automation management, its advantages are very clear: the amount of information storage, and each product has a unique ID number; reading and writing do not need light, you can read data through the external materials; long life in harsh environment; can be easily embedded or attached to the different shapes, types of products; reading distance is more far, you can write and access data, the realization of dynamic change labels; able to handle multiple labels; labeling data access is password protected, security higher; can RF ID tags are attached to objects to track location .
112 radio frequency identification system
Radio frequency identification system is mainly composed Tag, reader, antenna and so on, generally also require additional hardware and software support.
1) reader. Reader can be simplified into two basic functional blocks: high-frequency interface module (transmitter and receiver) and the control unit in two parts. RFID reader to read the information, and then send the information to a ground control center.
2) passive electronic labels. Electronic label from coupling components and ASIC (IC) components. Passive electronic tags that do not have their own power supply of the electronic label, issued by the reader and provide high-frequency energy. Analog front-end demodulator with RFID antenna absorption from the current, so after rectifier capacitance charging, and then by the regulator for the electronic tags after the power supply.
2 CAN bus technology
CAN is defined by the ISO serial communications bus, was originally used in the late 80's in the automotive industry. It has a high rate, high resistance to electromagnetic interference, high reliability and can detect any errors. CAN in the microcontroller need to communicate with each other, or between the microcontroller and remote peripheral device to communicate with each other circumstances is an ideal solution, in a variety of control system has been widely applied.
CAN has adopted a new technology and unique design, compared with RS485 outstanding reliability, real-time and flexibility. CAN has a multi-node network of the main characteristics of the high bus utilization, data transmission speed, scalability, and long distance communications, plus communications repeater distance of up to tens of kilometers, with reliable error handling and error mechanisms, individual node failure does not affect the operation of the entire communication network, real-time and good. In addition, CAN make up two-way communications half-duplex RS485 communication deficiencies, not only to achieve the upload location information when the need to also amend the underground in a real-time monitoring of contact information. Comparison, we can see, RS - 485 network in addition to hardware costs, the development of the difficulty of CAN-bus network than a bit of other performance advantages are not comparable. In the product updates particularly fast pace of today, if the time-to-market products towards the end of the maintenance of software development in terms of degree of difficulty with, RS - 485 hardware cost advantages also become very obvious, thus using CAN bus to replace the RS -- Bus 485 is a more thorough program.
3 coal mine personnel positioning system design
311 constitute the basic positioning system
Inoue underground system consists of two parts and equipment. Inoue equipment mainly by the Control Center (including servers) and shared network terminals composition; downhole equipment CAN bus as the main transmission channels, the development of the corresponding coal mine personnel monitoring node, with antenna, electronic label, transmission medium, in Following the browser, such as R and Monitoring Center articulated in order to achieve the positioning of underground work personnel and security management. System network structure as shown in Figure 1.
Figure 1 Positioning System network structure
312 Positioning System Principle
Positioning System Underground main security personnel and equipment monitoring. In the trenches, the operating side of the installation of monitoring交叉道口node, into the wells of staff in accordance with the requirements of the installation of an electronic tag to wear belts, or wearing a helmet fitted with electronic tags. RF ID reader through the fixed-frequency RF carrier signal to send to the electronic labels, electronic labels (staff wear) into the reader antenna work area was activated, and containing personal information via radio frequency signals to send and receive cards module launch; reader antenna to receive the electronic tag of the RF signal sent through processing, to extract personal information, through the Fieldbus Control Center sent Inoue, records Underground staff after location, time, activities such as track real-time information can be automatically generated attendance statistics and operations management, information reporting, improve management efficiency.
313 core components of positioning system monitoring node-RF ID
1) RF ID monitoring node hardware design. Monitoring node by the reader, microcontroller (MCU), CAN nodes. The design of RF reader chip is used in RI - STU - 650A, it has a strong anti-interference ability, communication, high speed, low power consumption, stable performance advantages. Taking into account the cost of such issues, the design of RF ID used in operating frequency is 915MHz, after a test to prove the reliability of transmission distance and data, etc., can achieve the functional requirements of the system. Reader with a microcontroller 89C51 between the use of SP I serial interface for communication. CAN node posed by the three parts: an independent CAN controller SJA1000, CAN drive 82C250 and high-speed optocoupler 6N137, as shown in Figure 2. CAN nodes in order to enhance anti-interference ability, SJA1000 is not linked directly with the 82C250, but by high-speed optocoupler 6N137 connected with the 82C250, thus achieved a very good on the CAN bus electrical isolation between nodes.
Figure 2 Monitoring node internal function modules Figure
2) RF ID monitoring node software design. Monitoring node is the use of single-chip software design and assembly language C51 mixed programming, including the reset module, anti-collision module, reading and writing module, communication module, the flow chart of Figure 3. When Tag be verified as legitimate, the reader was formally read / write Tag data, through information processing after upload by the CAN bus to the ground to monitor the heart. When Tag proven to be illegal, the reader response to the direct reset state, waiting for the beginning of the next read and write operations.
314 system to achieve the main function of
1) attendance management functions. Operating platform through a dedicated management software to go down on the number of personnel to go down, stay underground disaggregated statistics and other information to facilitate assessment, the achievement of staff attendance statistics and related management functions of the print statements.
2) safety and security features. Are stored in a database system based on historical data from the information, can quickly know the underground staff and the distribution of critical equipment, in the event of mine disaster, may be trapped on-site staff to locate and search for effective ambulance.
Figure 3 RF ID monitoring node software flowchart
3) production scheduling function. By calling the data in the database, you can query the distribution of underground staff and personnel in accordance with the need for rapid deployment to achieve Underground optimize the allocation of limited resources, to achieve a multiplier effect.
4 Conclusion
Coal mine safety is the eternal theme of production, personnel monitoring and positioning is to achieve the production of coal mine safety, one of the important guarantee. To this end this paper, time and attendance management system for mine personnel conducted a research and analysis on the current positioning technology research, put forward a RF ID as the core, CAN - bus communications network as a link to the coal mine personnel positioning system . After tests, reaching the desired objective, the system greatly to meet the real-time master personnel mine well into the dynamics of distribution and security management needs, enabling attendance management functions and
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