Research And Development Of Distributed Online Monitoring Device For Safe Operation Of Motor

As an important driving equipment in the production process,the normal working condition of the motor is related to the stability of the production system.Solving the diagnosis and maintenance problems of the motor can effectively prevent the occurrence of motor faults.It is understood that some domestic enterprises generally lack the ability to equip the workshop production equipment with testing instruments and complete maintenance tools,and still adopt the way of planned maintenance and operation personnel patrol inspection to maintain the motor.The work task is heavy and can not prevent the sudden failure of the motor.Therefore,this paper presents a design scheme of distributed online monitoring device for safe operation of motor based on embedded processing technology.In view of the characteristics of motor failure,such as temperature rise,vibration amplitude increase and working current increase,three physical quantities of temperature,vibration and current are selected as monitoring indexes,and the corresponding sensor and conditioning circuit are used to realize signal acquisition and processing.For temperature monitoring,PT100,DS18B20 and infrared temperature transmitter are respectively provided with three kinds of temperature measurement components conditioning circuit and interface.Users can select and switch according to the temperature measurement range,temperature measurement points,non-contact temperature measurement and other requirements by pressing the button.In vibration monitoring,an IEPE piezoelectric acceleration sensor HN600A100 which can output the original signal is selected.In addition to the vibration amplitude,its spectrum information can be obtained by Fourier transform.For the current monitoring,instead of the traditional system integration solution,the Hall current sensor chip ACS712 with simpler peripheral circuit is selected to convert the current of the secondary side of the current transformer into voltage signal,which is convenient for sampling and processing.The monitoring device is developed based on high performance STM32F407ZGT6 processor,with rich peripheral resources and strong data processing capacity.In order to make more reasonable and effective use of the embedded processor resources,the software in this paper is developed based on the FreeRTOS operating system.According to the system functions,the program is divided into multiple tasks,such as temperature,vibration,current signal processing,key scanning,display interface processing,communication processing,etc.In the process of temperature measurement of three kinds of temperature sensors,adjustable variables are used to determine the implementation of the temperature measurement function of the selected sensor.For the AC signal output by vibration and current sensor,sampling is carried out by means of triggering ADC with timer and implementing data handling with DMA.The sampling data is calculated by square mean root value to get the effective value.In addition,the signal spectrum is obtained by FFT processing and displayed.The monitoring device finally realizes the functions of online monitoring,parameter setting,spectrum display and bus communication under the mutual cooperation of various tasks,which is convenient for users to understand the running condition of the motor from the perspective of time domain and frequency domain respectively,and has certain reference value for the online monitoring of electromechanical equipment.There are 46 figures,3 tables and 63 references in this paper.