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Aiming at the problems of short distance, slow speed, large loss and weak anti-electromagnetic interference ability of traditional cable in data transmission of coal mine monitoring system, this paper studies the optical fiber transmission technology and the principle of optical transceiver module, and puts forward a single-mode single fiber optical fiber module transmission scheme between the monitoring equipment terminal such as underground sensors and the monitoring substation. The paper introduces the overall structure of the optical fiber transmission module, the sending and receiving principle of the optical module, and the application of the optical module in the sensor. Combined with the practical application, the signal transmission performance of the optical fiber transmission between the sensor and the monitoring substation is tested, which meets the actual application requirements.

A main fan monitoring system based on inverter control is designed. This paper introduces the working principle and working mode of data exchange between the inverter and the main controller. This paper analyzes in detail the problems and basic principles in the data exchange from the aspects of the monitoring mode of the master controller, the control mode of the inverter, the function setting of the inverter, and the external wiring of the inverter. The problem of stepless speed regulation of inverter in the demand is analyzed deeply, and the solution is provided and implemented.

A monitoring system for mine main fan is designed and built in Xudong Coal mine. This paper introduces the working principle of the monitoring system based on PLC controller and inverter control technology. This paper analyzes the problems in the design and construction of the monitoring system from the aspects of the main equipment composition, principle and structure, as well as the basic principles. This paper makes an in-depth analysis of the problem of non-stop wind switching in the actual demands, and introduces in detail the solution of the starting and stopping curve of the inverter in conjunction with the control of the butterfly valve, and implements it.

Starting from the perspective of method principle, system application, and technical characteristics, this paper systematically discussed the research progress of intelligent monitoring and early warning technology concerning fire risk of belt transportation, including inspection technology, distributed optical fiber temperature measurement technology, machine vision technology, wireless communication network technology and data-driven technology. Moreover, the advantages and disadvantages of those monitoring and early warning technologies were discussed. Based on the existing monitoring means of coal mine roadway and the development hotspot of digital intelligence, we proposed a new intelligent monitoring and early warning system for mine belt transportation fire and early warning: “Big-Intelligent-Mobile-Cloud” (big data, intelligent, mobile internet, and cloud computing respectively) coal mine belt fire monitoring system and multi-method coupling, three-dimensional, continuous monitoring system.

Aiming at the problem of improving the communication efficiency of RS485 bus, this paper analyzes the advantages and disadvantages of four measures: increasing baud rate, controlling transceiver control timing, multi-master communication and software improvement communication strategy, and proposes a strategy of group call and queue response for RS485 bus communication. This strategy is a bus communication software strategy, which does not change any hardware, uses group call and sequential response to reduce the number of host calls, sets priority queue to reduce the slave response time, uses simplified coding to reduce the data frame length without changing information, further shortens the polling cycle and greatly improves the communication efficiency. Through the RS485 communication test between substation and sensors, compared with the traditional method, the polling cycle and the response time of sensor transmitting emergency information are greatly shortened.

In view of the underground fusion of safety monitoring system and the emergency linkage demand of "man-machine-environment” in the direction of safety prevention and control under the development trend of intelligent mine construction, by studying the service characteristics, fusion methods and emergency linkage strategies of common downhole monitoring systems, combined with the safety prevention and control construction suggestions in the smart mine construction plan recently issued by National Energy Administration and local coal supervision bureau, a sub-station of edge coordination control was designed and developed to realize the underground fusion and emergency linkage of smart mine safety prevention and control system based on the sub-station of edge coordination control. This paper analyzes the key problems existing in the multi-system fusion and emergency linkage of common downhole monitoring system, discusses the technical design of multi-system fusion and emergency linkage method, and gives the technical route of “man-machine-ring” emergency linkage of three states.

A coal mine dangerous gas inspection system based on multi-sensor fusion technology is designed. The overall architecture of the system is divided into execution layer, network layer and decision layer. The monitoring platform and server in the decision layer and the mobile inspection robot in the execution layer realize data transmission through the network layer. This paper introduces the process of dangerous gas inspection and the module composition and function classification of inspection robot. The intelligent sensing module of the robot has the corresponding environmental parameter monitoring function. The robot can realize autonomous navigation and obstacle avoidance and dangerous gas concentration data acquisition by carrying a variety of sensors. The BP neural network algorithm is used to realize multi-sensor fusion, The real-time monitoring of various dangerous gas concentrations in coal mine underground environment is completed.

Taking the secondary sub node system of industrial Internet as the platform and the coal mine monitoring system as the access object, this paper analyzes the structure of the industrial Internet system and the key technologies required for the monitoring system to access the industrial Internet, and designs and develops an access gateway. The gateway is applied to the connecting end of the switch and industrial Internet in the monitoring system. The data sent by the monitoring sub-station of the switch is analyzed and processed, then packaged in JSON format, and passed into the industrial Internet cloud software through MQTT protocol. The practical application shows that the scheme has reasonable architecture design, good stability and superior performance, and provides a feasible scheme for monitoring system to access industrial Internet.

In order to solve the problem existing in coal mine safety monitoring system, the remote power-off based on the ground host computer is limited by the inspection cycle, which causes a long response delay and cannot be implemented normally when downhole communication with the surface network fails. This paper designs a method for autonomously realizing rapid remote power-off based on underground substations. This method is based on UDP network protocol with high real-time performance and the characteristics of multi-node data transmission. The application layer software implementation is to increase the response mechanism to ensure communication data accuracy and reliability, realize that when the environmental parameters of the coal mine are abnormal, the substations can independently realize the remote power failure. Laboratory tests and on-site industrial experiments show that the power-off method is faster and more stable than existing implementations.

This paper introduces the application of a monitoring system for multi-level lifting of inclined roadway in Tianzhu Coal Mine, and briefly expounds the system structure, working process and innovative application. The application of this system can effectively reduce the hidden danger of equipment in the track transportation of inclined lane and the hidden danger of pedestrians breaking into the rules and regulations during the lifting process, solve the problem of “pedestrians without driving, driving without pedestrians” from the technical level, and provide a good operation and management platform for the safety management of inclined shaft lifting.

This paper designs a wireless measurement system based on Wave Mesh. The system uses a 26 GHz high-frequency radar-type level sensor to collect coal level data. The radar sensor automatically converts the microwave signal into a coal level signal through its own electronic circuit part, and sends the output coal level signal to the STM32F104 single-chip microprocessor for conversion and storage. The Wave Mesh wireless ad hoc network technology is used to achieve long-distance wireless transmission between the ground measurement device and the upper computer. The system application shows that the coal level measurement system can facilitate the staff to monitor the changes of the coal level in real time, adjust the switch of the coal conveyor in time, control the coal level in a normal range, and ensure the safe and normal operation of the mine.

Based on the problem of weak remote power supply capacity of intrinsically safe power supply in coal mines, according to the centralized power supply mode of point-to-point power supply in the field, this paper analyzes the fault phenomenon caused by insufficient power supply capacity of intrinsically safe equipment when working in the field, and analyzes the reasons for the reduction of intrinsically safe power supply capacity. Based on the transient characteristics of intrinsically safe equipment and the internal resistance of power supply cable, the methods of restraining the impulse current of intrinsically safe equipment and raising the voltage through the middle of the line to reduce the line loss are proposed to improve the remote power supply capacity of intrinsically safe power supply. The experiments show that the remote power supply capability of the intrinsically safe power supply system can be effectively improved by the methods, and the power supply distance can be effectively extended under the same output power condition.

In view of the difficulties in the field program upgrade of mine sensors in underground coal mines, a remote program update method based on CAN bus and IAP function is designed to get rid of the dependence of embedded software upgrade on the programmer. By designing the Flash programming method and program starting and guiding mode of STM32F103 microprocessor, the on-line upgrade of mine sensors in underground coal mine is realized. This paper introduces the overall implementation framework, upgrades program structure and process, and elaborates the IAP program update principle. The mine bus sensor program can be updated online by field application verification.

This paper designs a kind of power integrated regional fire-fighting Internet of Things optical port substation, introduces the system architecture, discusses the analog signal isolation anti-interference, switching value and communication isolation circuit, power integrated power supply strategy, network optical port and other key technologies. Take STM32F429 as the control core, combined with the output circuit and control strategy of the sensor, the substation realizes the regional fire-fighting function of full isolation, patrol detection and early warning of the object connection, and integration of power supply and photoelectric port, which improves the anti-interference ability of the monitoring system.

To deal with the complicated environmental conditions of the coal mine, in order to improve the flexibility, accuracy and timeliness of information interaction between coal mine safety monitoring system and equipment, in this paper, a monitoring sub-station based on CAN bus multi-master communication technology is designed. Firstly, the hardware circuit of the monitoring sub-station is designed as a whole, and then the communication protocol of CAN bus is optimized. The optimized protocol can realize multi-master communication of monitoring sub-station through reasonable design of address domain and address arrangement. Multi-master communication monitoring sub-station can effectively support bus multi-master communication, and the communication efficiency and flexibility of the system have been greatly improved.

In view of the poor underground environment of coal mines, the difficulties in fiber welding, and the safety accidents caused by sparks generated by hot fused fiber at high temperature, a renewable fiber cold connection device was developed. Through the device, the underground optical fiber is cold-connected to eliminate sparks from the root source and reduce the underground coal mine safety accidents; through the OV slot of the device, the cold connection device is filled with the matching liquid for many times to ensure the reproducibility of the device. Starting from the structure, method, how to reduce the loss and how to realize the regeneration of the fiber cold connection in underground coal mine, this paper expounds the regeneration of the fiber cold connection in detail. Through field tests, it was found that the device has the functions of reducing the fusion time of optical fibers in coal mines, reducing safety accidents in coal mines.

Based on the drawbacks of wired sensors, a sensor based on wireless transmission technology is designed in this paper, which is applied in the belt transportation system of coal mine. Through the sensor design, wireless base station design, ZigBee network design, WiFi network design, the design requirements are met. The feasibility, reliability and real-time performance of the system are verified by wireless network analysis and network performance test.