Design And Development Of Pressure Supply System In Meter Calibration

Nowadays,The instrument has become more widely used in every industrial field. Especially, the dial pressure instrument. It has a lot of advantages, such as simple structure, convenient maintenance, which makes it get the favour of engineering personnel. To ensure the reliability, stability of the instrument in the work and the safety of operators, the instruments need periodic detection before the use and in use. But slow speed, low efficiency and poor stability are the main problems of the current instrument testing technology. which is difficult to meet the engineering requirements. Therefore, it is no time to delay to develop a fully automatic, efficient instrument detection system.This topic is aimed at the indispensable composition of instrument detection system module-the automatic pressure source.which realize the design of automatic pressure source with programmable logic control system as the core and with stepping motor, hydraulic cylinder as the hardware base.It requires high speed, precision and stability. But traditional algorithms can’t meet these. Therefore, combined with the characteristics of instrument verification, through a lot of experiment we decide:(1)when the value is in medium-pressure, we put forward the fuzzy PID control method that Fuzzy control is used to determine the PID parameters,on the base of a synthetic analysis of advantages and disadvantages of fuzzy control and PID control.(2)when the value is in low-pressure and high-pressure,we use control strategy of section step by step.these strategy control pulse output frequency.according to the difference of pressure difference and value, the method real-time adjusts the stepping motor speed amd avoids the phenomena of "overshoot".This system has improvement to the issues of low efficiency, large amount of labor and so on.It is made up of the step-down module, prediction module and PLC control module, etc, and realize the design of the automatic pressure source with fuzzy PID control strategy as the core. The experimental results show that the system has a fast speed, high precision and good real-time performance and stability, etc, greatly improving work efficiency of a complete set of the instrument detection device and having realized the automatic detection instrument, basically the system can meet the engineering requirements.