Remote Flow Measurement System Design Study

With the constant development and ripeness of industrial automation, computer technology and communication technology, metering method of flowmeter points to automation, intelligence and network. The measure system of long-range flow is an important subject for research of the industry of the instrument and apparatus at present because of its important practical value. At present, RS-485 serial communication way is mainly adopted in practical application, which can't meet the request for remote transmittion of data. So, this thesis focused on achieving the measure of long-range flow by adopting the remote communication technology of MODEM.This thesis has summed up the basic principle and methods of the communication of long-range flow measure system and the variety of communication network of it. On the basis of investigation and analyse of the current application and development trend of the technology, the measure of long-range flow was realized.The long-range flow measure system consisted of one PC and single chip microcomputer, which adopts PIC with high cost performance, mainly gathering the data of the long-range flowmeter. According to the different communication module between the flowmeter and the environment, three methods were adopted, i.e parallel communication, serial communication and single chip microcomputer receiving 4~20mA electric current signal from flowmeter. PC mainly showed and managed the data from flowmeter. The system utilized MODEM, public telephone network and accumulation, examining the communication algorithm to transmit the data. Utilizing VB6.0 to develop the friendly man-machine interface, which reads and stores the data of long-range flowmeter in real time. This thesis described the interference sources of the hardware and software of the system and anti-interference measures, which ensure the reliable running of the system.The experimental result of study shows: this system was reasonable in design, reliable in work, and easy to operation. Furthermore, it's anti-interference ability was so strong that it achieved the purpose of gathering and transmission of data by the slave controller and receiving of the data by the master controller exactly.