The Design Of Safety Valve On-line Testing System Based On Ethernet

Safety valve is running as a high pressure protection device in the production,which is applied in a wide range of industrial production and operations.In order to ensure that any accident would not be occurred in the production process,calibration of safety valve should be at least once a year.At present,the main method for application is offline verification method,it can conduct an overall check of the safety valve,but the production equipment needs to be stopped when using this method,and it needs to dismantle the safety valve before overall check,the production efficiency would be low,and it would leads to economic losses.Aiming at the problems like complication of removal,long time to check,Comprehensive cost high,which are happened in offline verification method,the design scheme of on-line testing system which possesses network interface function,combined with existing online safety valve testing technology was designed in this paper.The modular circuit such as sensor signal conditioning circuit,AD conversion circuit,the flow of clock frequency division string and transformation logic,data storage logic were designed by 16 bit high precision AD converter,FPGA+ARM architectural pattern and Ethernet data transmission and so on.Finally,an online testing system of safety valve which is based on Ethernet was designed,it has advantages such as convenient to dismantle,high precision of acquisition.The solution to conduct long distance data transmission use Ethernet after considering safety production.The drive of related network card hardware which is based on embedded operating system was researched in this paper,the function of Ethernet remote data transmission was realized via the call of the upper correlation function in embedded operating system.Aiming at the demand that the high accuracy of the safety valve related parameters,offering clock to AD converter only by FPGA was selected,the design of control was in charge of ARM,it ensure acquisition accuracy,avoiding the influence of executive command time of CPU.Aiming at the question that it hard to measure displacement,the method based on polynomial fitting to remove trend term was researched,displacement was solved quite accurate by acceleration.Experimental results show that,the design of safety valve on-line testing system based on Ethernet can be used for the correlation parameters of the safety valve jumping tests,fully meet the needs of this application,it has advantages such as high precision and easy disassembly,low-cost as well as merit.