The Research Of Differential Pressure Transmitter Detection Devices With High Static Pressure

Differential pressure transmitter has been widely used in various industries because of its advanced design principles, completed specification and easy-to-use installation. Due to the workplace of differential pressure transmitter generally exist the static pressure, and has a certain degree of influence on its performance, so JJG882-2004"Verification Regulation of the Pressure Transmitter" give a supplementary regulations of differential pressure test of the differential pressure transmitter with high static pressure, it is said that "Static pressure checks of the differential pressure transmitter that compulsory verificated should be maintained at a working pressure of state". In response to this situation, this paper designed and developed a new differential pressure transmitter detection devices with high static pressure.Firstly, the development status of the domestic and foreign high static pressure detection device was analysised and compared at home and abroad, taked the metal capacitive differential pressure transmitter for example to introduce the reason of the static pressure effects, and proposed the design of the device through the analysis of the previous similar device. Secondly, pressure enclosure design, interface design, and hardware structure are introduced, then according to the test requirements of pressure differential pressure transmitter with high static, the corresponding lower machine control system and upper machine calibration system were developed. The lower machine control system used PLC as the core to achieve the control of stepper motors, valves, vacuum pump, and the reading of sensor analog, limit switch signal, through the connection between the electrical components. The upper machine calibration system adopted the Lab VIEW to write system interface for the realization of parameter settings, test monitoring, data management, and so on.After a series of experimental tests, differential pressure transmitter detection devices with high static pressure has a good test performance, and the developed calibration system has friendly interface. Under the static pressure0-4MPa, the repeatability of differential pressure transmitter is less than0.2%, and the expanded uncertainty is also less than1/4MPEV, certainly in comparison with the standard facility, the results show a good agreement. So the way to use differential pressure transmitter detection devices to detect differential pressure transmitter is practicable. At last, a new method was gave to correct the static error. At present, the device has been put into operation and the system operates steadily. It can realize rapid test of differential pressure transmitter with static pressure (0-4)MPa, differential pressure (0-400)kPa.