Direct digitalized pressure transmitter and measuring method thereof

Abstract

The invention is a direct-digital pressure transmitter, including the capacity presure sensor; the resonant circuit used to receive the capacity changing value and directly transform it into the oscillation frequent signal; the SCM, the external RAM and the input equipment, used to adjust the measuring range and input the measuring parameters; the display cell. The method as follows: initialization setting, and operation and judgement according to the input key value: if measurement, directly get the pulse frequency and make the interpolation operation to get the pressure value, then display the result, if parameter setting, read in the given pressure value and measure the pulse frequency and calculate the corresponding pressure value and save it to RAM.

Description

technical field [0001] The invention relates to a sensor and its measuring method, in particular to a direct digital sensor and its measuring method. Background technique [0002] FR1511 pressure transmitter is one of the most widely used sensors in industrial process control. It can measure not only pressure but also flow. For capacitive pressure transmitters, the traditional mode of "sensitive measuring element - linear amplifier - analog output (4-20mA)" has been used for decades. Although, in the past two years, some research units at home and abroad have carried out intelligent transformation on it, and developed a so-called "intelligent pressure sensor", that is, adding A / D conversion on the original basis, that is, as figure 1 The shown "sensor - analog amplification - A / D conversion - microcomputer processing", but it still does not change the traditional pressure transmitter mode, and, even this slightly improved mode, still exists Man...

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Problems solved by technology

Although, in the past two years, some research units at home and abroad have carried out intelligent transformation on it, and developed a so-called "intelligent pressure sensor", that is, adding A / D conversion on the original basis, that is, as figure 1 The shown "sensor - analog amplification - A / D conversion - microcomputer processing", but it still does not change the traditional pressure transmitter mode, and, even this slightly improved mode, still exists Many disadvantages: Due to the use of very complicated analog amplifier circuits and expensive A / D converters, the production process of pressure transmitters using this mode is complicated and the cost is high; The pressure transmitter has a large volume, it is not easy to improve the measurement accuracy, and the reliability is poor

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