Research And Design Of Transmitter On Underground Pipeline Inspection System

Underground pipelines are the main tools for long-distance transmission of oil,natural gas,and other energy,it plays an important role in the development of the national economy.The problems such as pipeline corrosion and damage seriously affect the energy transmission efficiency of pipelines,causing waste of resources.Prevention of pipeline corrosion is particularly important.The application of anti-corrosion coating on the steel pipes of pipelines is the most common pipeline anti-corrosion measures.The anti-corrosion coating can prevent and reduce the corrosion of buried pipelines.Regular detection and evaluation of pipeline anti-corrosion layer can detect pipeline problems early and reduce the incidence of pipeline accidents.The underground pipeline inspection system generally consists of transmitting and receiving parts.The emitting part mainly produces sine wave positioning detection signals and AC corrosion detection signals applied to the pipeline;the receiving part mainly detects the attenuation of positioning detection signals and corrosion detection signals to evaluate the pipelines.The degree of damage to the anti-corrosion layer and the location of damage to the pipeline.The paper based on ARM architecture Cortex-M3 core microprocessor STM32F103 on the underground pipeline detection system launch circuit research and design,launch circuit is divided into the power circuit,alternating current circuit,sine wave voltage generation circuit,human-computer interaction circuit in four parts.sub-module method to achieve the controller IP core,the main work is as follows:1.The power supply circuit uses a current-mode PWM(Pulse Width Modulation)control chip UC3842 as the main control chip to design a switching power supply to convert the 220V mains power into the system's required operating voltage(48V?15V?5V DC voltage).2.The alternating current circuit uses SPWM inverter technology and PID control technology to output a stable alternating current with a frequency of 4Hz and amplitudes of 100mA?300mA?600mA?1A?2A?3A,respectively.The signal is used for the corrosion detection of the corrosion of the underground pipeline and the positioning of the damage point of the anticorrosion layer.3.Sinusoidal voltage generation circuit adopts DAC(Digital to Analog Converter)of STM32F103 microprocessor to generate sine wave voltage signal with frequency of 4Hz?128Hz?640Hz.It is passed through low-pass active filter circuit and OCL power amplifier circuit to filtering and power amplification,the outputting sinusoidal voltage for pipe positioning.4.The human-computer interaction circuit consists of output mode selection,LED fault indicator,LCD screen display and touch control circuit.Through simulation tests,the underground pipeline detection system emission circuit can generate stable alternating current signals with an output frequency of 4HZ,current values of 100mA?300mA?600mA?1A?2A?3A,and can generate frequencies of 4Hz?128Hz?640Hz sine wave voltage signal,to achieve the basic functions of the underground pipeline detection system launch circuit.The stable circuit performance and low cost make a useful exploration for the nationalization of related products.