Research And Implementation Of PIC Microcontroller-based The LNG Cryogenic Equipment Monitoring System

The paper mainly discusses the research process of the LNG low-temperature equipment monitoring system based on PIC microcontroller, the system is achieved by PIC16F1939 microcomputer as the main control chip produced by MICROCHIP company, the collection, treatment and display of the low-temperature equipment monitoring data of LNG can be realized by bringing the sensor, LCD display, and touch screen chips in the coordinated control. This paper expounds requirements analysis of the LNG low-temperature equipment monitoring system, the hardware circuit design and presents theory, method and design scheme of the upper computer and lower computer system software in detail.The LNG low-temperature equipment monitoring system including two parts: a upper computer and a lower computer. The lower computer mainly includes acquisition control system module and hubs system module two parts. Acquisition control system module is mainly responsible for acquiring liquid level, hydraulic and temperature data of each tank, and then the collected data will be smoothed to realize error reduction, after that it will be sent to the hubs system module by I2C buses; Hubs system module is mainly responsible for receiving the state data which was sent by acquisition control system module and collecting engine pressure data, after processing the data it will send the data Bitwise transmission by MAX485 chip to the upper computer. The upper computer mainly includes three parts: the upper computer control system module, LCM display module and touch screen response module. The upper computer control system module is responsible for receiving information packets from the lower computer, and by means of the critical calibration equipment to minimize the processing data errors due to reasons such as process equipment. LCD module is responsible for displaying the data according to the state of tank accurately and presenting the corresponding operation buttons. Touch screen response module is to response to the touch events and realize the interaction of user and equipment.This paper firstly analyzes the background and the developing situation of the LNG low-temperature equipment monitoring system, and then introduces concretely something about hardware design scheme such as chip selection, data acquisition theory, and interface circuit design. Combining with hardware design, this paper gives a detailed description of the design idea of the upper computer and the lower computer, data processing technology, communication mode; data display mode and the collaborative operation between modules, and makes a deep research into the concrete realization method of the system. At last the software simulation test and hardware test is made and something about the system's practicability, stability and accuracy are also taken in to consideration.The research and implementation of LNG low-temperature equipment monitoring system is fully complied to the fast development tendency of our country civil'demand for LNG low-temperature equipment monitoring systems , it solves the prominent problems lie in the Similar equipments : big System error, the low efficiency , the use of inconvenient etc. the systems have been adopted in the auto industry which now has been in the testing phase, it is well believed that it will get better economic benefits and social benefits in future.