Third International Workshop on Advanced Computational Intelligence August 25-27,201 0 - Suzhou, Jiangsu, China

Design and Research on Monitoring and

Alarming System for Mine

Panfeng Chen , Lei Shi, Jianfeng Wang, Lidong Chen, Shiguang Liu

Abstract-In this paper, the configuration character

-istic of the safe parameter measurement and alarm

system used in a new type mine is introduced. The system

is made up of wire communication and radio

communication with a topological structure. Then, it

respectively introduces the hardware and software

construction, the working principle and the method of

design, which makes the enhanced single chip

microcomputer STC12C5612AD as the core of detecting

instrument, the STC12C5630AD as the core of

coordinator and IPC (Industrial Personal Computer) as

CPU. The three-class computer communication system,

which integrates measurement, alarm and management,

has reliable operation and convenient using, and it

especially adapts to the system of parameter detecting

and alarm in the mine with decentralized monitoring and

centralized management.

I. INTRODUCTION

THE quality of mine safety parameters (mainly gas and other harmful gases, temperature and humidity,

ventilation, etc.) of monitoring and alarm system directly relates to the safety of mine. Currently, monitors

widely used in mine are single monitor detecting with manual observation and recording, which bring great

inconvenience for users, especially in the data management and analyzing. In addition, it is not convenient to analyze the distribution gradient and identify the source direction of the harmful gases. Therefore, aiming to the conditions of

different mine structure and scale, to enhance the quality of monitoring and management the harmful gases, it is practical to design a topology structure for monitoring and alarm system of safety parameter of mine.

II. SYSTEM HARDWARE DESIGN

Hardware topology of the system is shown in Figure I. For the IPC (Industrial Personal Computer) has a strong

analytical capacity and a high speed processing [1], and its interface can display rich information, especially its high

reliability is easy for centralized management in the central control room, the central control computer of the system

uses an IPC. The coordinators of the system are placed in a appropriate work surface, and many of them are connected

with the IPC in a wired communication way, at the same

Panfeng Chen and Lei Shi et aI. are with the Electrical and Mechanical Engineering College, Hebei Normal University of Science and Technology, Qinhuangdao, Hebei Province,China(email: chenpanfeng1980@126.com}.

Jianfeng Wang is with the Mathematics and Iinformation Science and Technology College, Hebei Normal University of Science and Technology, Qinhuangdao, Hebei Province,China( email:wjfqhd@126.com}.

978-1-4244-6337-4/10/$26.00 @2010 IEEE 389

time ,each of them is connected with lower coordination or stand-alone monitoring instruments (the bit from the

machine) in a wireless communication way. The hardware and software of the topology structure of the whole system

all adopt modular structure, so that the users can select reasonable hard and soft resource to achieve flexible

configuration and high cost performance according to the actual situations.

A. Monitoring Instrument Design

It is not only a whole terminal of the system, but also a relatively independent monitoring instrument. Moreover, it

can be portable carried and also can be put in a fixed shelter

as a fixed monitoring points. Thus, the monitoring data can be readily observed and recorded by the users; at the same

time, the data are transmitted to a central monitoring room through the coordination by wireless communication devices.

Instrument hardware structure Monitoring instrument hardware block diagram is shown in Figure 2.

One of the significant characteristics of the design is adopting a high performance microcontroller

STCI2C5612AD [2], which has a 4-way on-chip lO-bit A / D converter, compared with the high cost performance

microcontroller AT89C52. The chip can be used for detection and treatment including gas and other harmful gases, temperature and humidity, ventilation, etc, which can directly or indirectly improve the reliability and

miniaturization of the monitor. A machine cycle of the monitor takes up only a clock cycle, which makes it run 8 to

12 times faster than the latter, so that it can give a stable transmission for large data stream. In addition,

STC12C5612AD series of microcontrollers have several pins package (20, 28, 32, 40, and 44), so we can select it

flexible according to need. It can not only meet the use but also make the system minimized. The wireless

communication device is nRF401 transceiver [3]. In this

paper, we mainly introduce the principle of nRF401 and

connection method with MCU.

The working principle and the connection method of nRF401 transceiver The nRF401 wireless transceiver chip is produced by Norway Nordie Company, and the chip can receive wireless data transmission and emit signals in one chip, which works in the two frequency bands of

433.92MHZ and 434.33MHZ, and send data by using FSK modulation and demodulation techniques. The maximum

operating speed of it is 20Kbitls. The typical transceiver circuit is shown in Figure 3, in which TXEN is transmit /

receive control terminal, PWR _ UP normal/standby control terminal, CS frequency selection terminal, TXD

RS-485

IPe

Sensor

node

IIPI

Sensor

node

IIPQ

Sensor node

nmPI

Sensor node

nmPQ

Fig.l. The topology diagram of monitoring and alarming system for mine

P2.0-3 Keyboard

PO•O-7

P2'4-6

rJ). � n P2'7 �

P3-7 N n U'I 0'1 �

N > P3.4 � P3.5

P3.2-3 nRF401

transceiver

Fig.2. Block diagram of monitoring instrumentation

data receiving terminal, RXD data sender terminal, and

TXD and RXD can be directly connected to serial port of microcontroller.

B. Coordinator Design

As shown in Figure 1, the coordinator is the main passage of the entire system information. It is a relatively independent monitoring instrument, meanwhile, it collects

the data of all monitors of next level by a wireless communication way and transmits the data from itself and

the collected by wire communication and interrupt mode to the IPC. Compared several solutions, it is appropriate to

choose the STC12C5630AD as the coordinator of the MCV. The diagram of the coordinator connecting with IPC is

shown in Figure 4. Considering the bad environment in mine, the failure rate

of the terminal instruments might be higher. If the coordinator has not received any signal from terminals

several times, it will send the report to the higher IPC, and the failure location of the terminal devices can be seen on

390

Fig.3. nRF401 transceiver peripheral circuits

the IPC screen, so that it can be timely dealt with.

Backup power is very important for the coordinator. In the sudden accident, power supply system of the mine may be affected, but backup power can start in such circumstances, and the system switches to power-saving

mode. So that it can provide data for the recovery and

rescue incidents to provide security guarantees even in the case of no external power supply.

There has RS-232 serial standard interface in IPC [4], but its transmission distance does not exceed 15m, which is not

enough for the safety parameters of the mine detection and alarm system. The communication distance is usually far

away, therefore, a RS-485 serial communication card is designed for IPC in the system in order to obtain the change

from the RS-232 serial interface standard to the RS-485 serial interface standard [5]. After the protocol conversion

of the sending terminal and receiving terminal, RS-485 protocol is relatively transparent for data transmission, so

the data sending and receiving can be still carried out by RS-232 serial interface for remote transmission and control.

OJ RS-485

interface

circuit

The monitoring instrumentation

of taking STC l2C5630AD as the

MCU

Fig.4. coordinator and its IPC connection diagram

III. SYSTEM SOFTWARE DESIGN

Software system mainly consists of operation procedures

of monitoring instrument, communication procedures and

running program of IPC.

A. The monitoring program design of the monitoring device

The application program of the instrument uses modular structure, which goes with the hardware configuration. The key and difficult point of the software is how the main

program completes a full functional system monitoring program combined the subroutine of different hardware

configurations. It is mainly composed of the main program, the subroutine of data peripatetic collection and disposal, the subroutine of displaying and the communication interrupting service program and so on.

The main subroutine of interrupting service is in respond to the interrupting request of the major relay station, which

will send the four parameters collected in this node to the relay, according to the appointed structure. Due to the time

asynchronous transmission of the coordinator and the terminal devices, in order to improve the reliability of

wireless communication, the leading symbol 55H+FFH is added before sending the valid data. If the received leading

symbols are correct, the valid data can be received with the frame of 55H+FFH plus the terminal code and valid data. The terminal devices and the coordinator communicate in

time-sharing through digital addressing coding, and each terminal device has its own addressing code. If using 8 bit

encoding, each coordinator can link 256 terminal devices. Usually, the terminal devices are monitoring the state

parameters of circuit by cyclic detecting. When the serial port receives the same addressing data with the machine,

then it relies on the collected data in the form of interruption. The coordinator circuit receives data from its

terminal devices.

B. The software design of master-slave mode

Both the IPC and the coordinator or the coordinator and the monitoring devices, are both based on master-slave mode to communicate. The upper computer (the IPC in the

wire communications and the coordinator in the wireless communication) is the host machine, and the lower machine

(the coordinator in the wired communication and the monitoring instrument in the wireless communication) is the

slave machine. In the communication, although they have differences between wireless communication and wire

communications in the hardware, the software flow is same.

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The host machine asks for the data from the machine again and again according to a fixed sequence in proactive manner in the main program, and the slave machine answers the request of the host by interrupting.

IV. CONCLUSION

The monitoring and alarm system of the mine safety

parameters (mainly includes the amount of gas and other harmful gases, the temperature and humidity, and the

ventilation) is still in a developing stage, but the advantages have been exposed in many ways: the modular structure is

adopted by its hardware, software and other parts, which will makes the system flexible to adapt to different mines in

size condition and requirement. The combination of wired and wireless communication according to features of mines

makes the system reliable and the layer is clear and easy to manage. Every aspect is designed to be a minimum system

in premise of the reliability and choose the low-power device to make the system portable, energy saving, and low

price. The field test shows that the mine monitoring and alarm

system introduced in this paper has some characteristics such as low power (battery power for up to 2 years), stable and reliable in work (in 2-year trial period it is error free and reliable operation), and the system flexible setting up.

These advantages will enable it to have a bright future

and a broad prospect.

REFERENCE

[I] R. Jin, D. Yan and G. Li, "New method of orientation and calibration for gas detector", Coal Science & Engineering, vol. 10, no. 2, pp. 11l-1l3,2004.

[2] J. Li, J. Shao and Z. Zhang, "Programs for DSI8B20 Based on STC12C Single-chip Computer", Foreign Electronic Measurement Technology, vol. 28, no. I, pp. 23-26, Jan. 2009.

[3] Z. Liang, G. Hua and D. Yu, "A Cutting Temperature Measurement System Based On nRF401", Techniques of Automation and Applications, vol. 27, no. 4, pp. 92-94, 2008.

[4] L. Zhang, "Multi-MCV Serial Communication Based on the RS-232 Protocol", Techniques of Automation and Applications, vol. 28, no. 4, pp. 54-55, 2009.

[5] J. Li, J. Shao and Z. Zhang, "A Design and Debugging on Master­slave RS485 Applications System", Electronic Technology, pp. 44-46, Feb. 2009.