The Research Of Remote Monitoring And Control System For Water Temperature And Level Based On CAN Bus

With the social development and progress, the fieldbus technology is widelyused in various measurement and control field. Temperature and water levelmonitoring and control system has better solved the inherent shortcomings of the solarhot water project. However, the current system is a stand-alone work or using theRS-485 bus. They cannot meet the new requirements for monitoring and control ofsolar hot water. Fieldbus-based distributed measurement and control system hasbecome the development direction of the temperature and water level monitoring andcontrol system. This paper designs a set of monitoring and control system for solarhot water project, to achieve distributed control of solar hot water. The system ismainly composed of the master, slaves, and CAN network.The introduction part of this article first introduces the background of topics andresearch significance, then introduces the two stages of temperature and water levelmonitoring and control system development. Analysis of the shortcomings anddeficiencies of the existing system, and concentrated summarizes the advantages ofthe fieldbus system. We propose that the fieldbus application to temperature andwater level measurement and control system.The next one is the overall structure of the system design, detailed illustrates thefunction of each part and gives the block diagram of the various parts. In the busselection, this paper compares several common fieldbus and details the characteristicsof the CAN bus. In view of the versatility, development costs and openness, thesystem uses CAN bus. This part provides a basis for hardware and software design.The third part is a brief introduction to the CAN bus, including LLC and MACfunctions, signal bit value indicates and data frame structure. Finally, according to the system design requires, we design CAN high-level application protocol andcommunication processes for this system.The fourth part is the design of the hardware. This part designs a microcontrollerperipheral circuit, power circuit, the CAN interface circuit, liquid crystal displaycircuit, the water temperature measuring circuit, the water level measurement circuit,the relay control circuit, as well as real-time clock circuit. And test the temperatureand water level measurement modules then analyze the test results. Finally discuss themaximum distance of the bus, and analyze the four main factors of communicationdistance.The fifth part of this paper is the design of the software. First, paper brieflydescribes the software development environment. Second, paper gives CAN receiveand transmit subroutine. The master and slave software are designed, then paper givesthe work flow chart and the main segment of the program.Finally, solutions and suggestions are proposed towards defects in the design.