Design And Implementation Of Ultrasonic Flowmeter Digital Communication System

The fast development of Internet technology and computer technique makenetworked instruments be outstand from traditional instrument, it has become a trendsof intelligent instrument, and is emerged in the digitized instrumentation and controlsystem of nuclear reactor.While measuring the molten salt flow rate of the TMSR, data acquired by thedigitized ultrasonic flowmeter needs to be firstly converted into analog4-20mA signalby additional DAC, then it can be read by the dedicated ADC of PLC, and finallytransferred to the network of DCS.Based on the previously finished ultrasonic flowmeter prototype with basicprinciple of transit-time difference measurement, an Ethernet interface is designed andextended for flowmeter’s network connection with the DCS. Considering the controlsystem of TMSR molten salt loop is developed by using EPICS, a dedicated EPICSdata interface for flowmeter is designed and implemented in IOC/OPI PC to ensureeffective communication between the flowmeter and the EPICS IOC/OPI under theserver/client infrastructure. While designing network interface, the DM9000is chosenas network chip of the ultrasonic flowmeter, and the digital signal controller (DSC) ofthe ultrasonic flowmeter (TMS320F28335) is utilized to control the communicationprocess. Device driver for DM9000chip was developed on DSC together with the uIPprotocol’s transplantation. A client program for data transmission is developed on theclient side. In the remote IOC/OPI computer, a server program for data reception isimplemented together with a widget for real-time flow rate monitoring. In addition,Hamming window is used for filtering the interference noise of the ultrasonic, thusimproving the accuracy and reliability of flowmeter measurement.