Multichannel Intelligent Flow Recorder Based On C8051F020

In the engineering detection, flow measurement is improtant. Grasping the message of flow is the basic of the production running safely and economicaly. With the development of social and science, flow measurement becomes more important to the national economy. The technology of flow measurement has been applied to agriculture and industry, energy management, national defense construction, aerospace, scientific reserch, biological engineering,environmental protection and all fields of people’s life.The flow measurement is a complicated technology, it is not only because the demands of accuracy and reliability become higher, but also the principle and methods of flow measurement are different when the fluid is different because of the objects that are measured being diverse and complex. The article analysis the method of how to compsensate the density of liquid, gas, saturated stream and overheated stream according to the physical characteristics of fluids that are measured:the density of liquid changes little when the temperature or pressure changes, it can be compsensated by multiply a coefficient; the cofficient of compressed gas can be get by the ideal-gas equation; the density of saturated stream can be segmentally compsensated through least square method according to the table of density of saturated stream; the density of overheated steram can be compsensated through the method of isothermal curve and interpolation. The formulas of flowmeters are different when the measuring principle of sensors is different. Knowing the volume flow, the mass flow can be get by multiplied a coefficient.Based on the principle of measurement that introduced above, the multichannel intelligent flow recorder based on MCU C8051F020is designed. The instrument can measure and record flow, it not only can measure the parameters of liquid, but also can obtain the historical curve and data at length365days. The multichannel intelligent flow recorder set three flow measurement channels. each channel can be connected with Pt100, signal of pressure transmitter and signal of flowmeters. the signal of flowmeters can be analog voltage, current and square wave, and can finally measure the volume flow rate, the mass flow rate and the accumulated flow. The instrument uses LCD to display, it not only can display flow in the form of digital, but also can observe the change of flow in the form of graph. According to FLASH and DS1302that connected to the MCU, the user can obtain the historical curve about flow and the historical data. In addition, the insturment can exchange data with computer, the centralized management of the data can be realized.