Design Of Low Power Data Acquisition And NB-IoT Transmission System

When data collection and transmission are carried out in unattended situations such as industry and agriculture and without a stable supply of mains power,the system often uses battery power supply.Therefore,the battery life is a key factor for the data acquisition and transmission system to maintain long-term stable operation.In addition to choosing a large-capacity battery,reducing the power consumption of the system circuit as much as possible is the main technical route to prolong the service life of the battery.In order to meet the data collection and transmission needs of unattended for a long time,no stable supply of mains power and unable to use solar cells,This dissertation designs and implements a low-power data acquisition and NB-IoT transmission circuit system,and makes an engineering prototype,which can remotely collect on-site analog signals and digital signals,and upload the collected data using NB-IoT wireless communication technology to server cloud platform for remote monitoring and management.The system focuses on the research and realization of data acquisition and transmission technology under low power consumption from the following three aspects:(1)Hardware circuit design.The system is powered by a disposable lithium battery or optional solar battery.In order to ensure the endurance of the disposable lithium battery when it is powered alone,Reasonably carry out hardware circuit design on the basis of fully considering the power consumption of each functional module and the low power consumption performance of the chip;Design a power supply circuit that is easy to switch and control to reduce the response time of system state transition;Design lithium battery voltage detection circuit,real-time monitoring of lithium battery power information.(2)Software design.The system can dynamically adjust power consumption according to load changes during analog data collection.Perform refined management of each functional module,and immediately disable related peripheral interfaces such as ADC,SPI,USART,etc.after the module's work is completed.Enable the MCU sleep strategy,control the MCU to enter standby mode when the system is in the idle state,and reduce the discharge current of the lithium battery.Select GPS hot start boot mode to reduce system timing and positioning power consumption.Before the MCU enters the standby mode,set the relevant I/O line to high impedance state.(3)Dynamic power management.Analyze the power consumption of each circuit function module,reasonably schedule high power consumption function modules such as NB-IoT communication,RS-485 communication,GPS timing positioning,and reduce their working frequency.The system uses dynamic power management technology to dynamically allocate resources to each functional module/chip when the system is running.When the module is required to work,the system turns on the power supply of the module to complete the corresponding task;when the module enters the idle state,the power supply of the module is turned off,and the module enters the shutdown mode to avoid unnecessary power loss.This system realizes the functions of data collection and processing,data verification,data storage,data transmission.Through the software and hardware joint debugging of the system engineering prototype,the function and power consumption of each module are tested and analyzed,it is proved that the design meets the functional requirements of the system,and can work for a long time in an environment where there is no one on duty,without a stable supply of electricity,and solar cells cannot be used.