Research And Experimental Study On Without The Order Of Distributed Electrode Switching Device

This study of this paper is a part of "Eleventh Five-Year" national technical supportplan "old mine empty area detection and disaster prevention key technologies andequipment". The transient electromagnetic method, pseudo-random multi-frequencydetection method and high-density electrical method are used in project to a variety ofgeological exploration. According the water hazards situation and characteristics of ourcountry, the prevention planning are presented.Tunnel excavation engineeringwater-irruption is the phenomenon of a large water suddenly rush into underground cavernand mining in the process of mining and ore deposits. Tunnel water-irruption is a leadinggeological disaster about engineering and mining, it is also engineering geologicalproblems. In recent years, the accident of water bursting tunnel significantly increased, theharm of it is also more and more serious. Tunnel water-irruption has become the maingeological disasters of mine. Tunnel water-irruption not only seriously impact on people’slives and economic development, but also damage to the impact of mining enterprises, andthe influence of the damage the mining enterprise, making follow-up the momentum ofdevelopment of the mining enterprises restricted.For this reason, the national science andtechnology support project plan to study the mine old mined-out area detection andequipment and the key technology of disaster prevention. The content of this paper is abouthigh density resistivity. The main research is distributed without the order of the electrodeswitching device design and combination of several field experiments, the imperfectaspects of the instrument to improve the design.Distributed electrode switching device is a intermediate carrier of emission current istransmitted to the earth, the whole system way of working is controlled by it. For thosequestion which are electrode switching device number fixed, the location of a unified workordered and not interchangeable between the survey lines and the survey lines. The paper presents the electrode switching device based on the series without order. Distributedwithout the order of electrode switching device is composed of the main electrode,electrode and RS-485bus. The control MSP430microcontroller in the electrode deviceused the serial port and RS-485bus transceiver SN65HVD08communication interface tocomplete the signal communication between the electrode and the electrode and theelectrode with the host. Each RS-485bus on top of it is primarily electrode, others areordinary electrode. The host signal to the main electrode when RS-485bus in the workhave connected, the main electrode analysis which signal is to pass or to control theelectrode in section line after the host on the main electrode number. So the signals sentdown in the series electrodes to control the switching of each electrode. Reliability andstability of the electrode switching signal directly affects the high density electricalinstrument field exploration.The high density electrical instrument devices measure only collects the voltagesignals which are inspired by the launch on the earth, but earth resistivity inversioncalculation needs to know the current size, according to this problem paper puts forwardimproving design and research. It includes the launch of the current design and feedbackcalibration constant current control research. The two improved devices solve the problemof using estimated values but not accurate when inversion current data. The instrumentincreased current collection calibration in order to explain the results more accurately. Thecurrent transformer make the current in the circuit change to the easy measurement voltagesignal, using MSP430F1611microcontroller to own A/D module transform it into value andsend it to PC through a serial port, Stored in the Excel spreadsheet by VB. Constant currentcontrol is another solution which is on the basis of detecting emission current, it put currentvalue back to the MSP430F1611microcontroller, the microcontroller judges the size of thecurrent value and controls the size of the resistance of the following digital potentiometerMCP42010, changing duty cycle of the PWM regulator-UC3846in instrument power tofeedback control supply voltage and current for keeping the stability of the emission current.But the rise and fall of the supply voltage can not be completed in a launch period, whichwe need to increase the number of launch cycle to ensure the power supply have enoughtime to complete the adjustment. Such the instruments in the field exploration work time will increased exponentially, this method is not desirable from the angle of the instrumentand an economic point of view.The result obtained by the high-density electrical instrument is consistent with thedetection results of seismic wave method on AnTu mine joint exploration experiment withseismic method instrument. The experiment has achieved good results.Through theexperiment, the function of the instrument is verified, we also found that some areas in theinstrument is need to improve, it provide the basis for the next step design work.The testing part mainly include electrode device test and improve device testinginstruments, electrode device test contains roll call response test and grounding resistancetest, the test results show that distributed without the order of the electrode device meetrequirements of the design, the RS-485bus meet the reliability of signal communication.The instrument improved device test includes current sensor testing, amplifier circuittesting, absolute value circuit testing and digital potentiometer testing. Test results show themodules performance is good, meeting the design requirements.Thesis mainly completed the distributed without order of electrode switching device,to the instrument not perfect place puts forward improving design, to mine field explorationexperiment and put forward some suggestions for improvement of high-density resistivitytesting device.