RTC clock calibration method and industrial field calibration device

Abstract

The invention provides an RTC clock calibration method and an industrial field calibration device. According to the method, the cycle number of a reference clock or the cycle number of the reference clock subjected to frequency multiplication through a PLL circuit is collected through a set first timer, the cycle number of a work clock is collected through a set second timer, and the second timer and the first timer are enabled to synchronously start counting and synchronously end counting within preset time, thereby realizing RTC clock calibration of low-frequency crystal oscillator as working clock. According to the method, a high-frequency crystal oscillator of the device as a reference clock is used for calibrating a low-frequency crystal oscillator of the device as a working clock, thus the RTC calibration can be automatically executed by the calibration device, the calibration cost is saved, the dependence of the RTC calibration on the online client device is reduced, and the calibration device is suitable for the industrial field calibration device.

Description

technical field [0001] The invention relates to calibration technology in the field of industrial instruments and meters, in particular to an RTC clock calibration method and an industrial field calibration device. Background technique [0002] The real-time clock RTC (abbreviation of Real-time Clock) has technical advantages such as low power consumption and independent power supply. It is widely used in industrial field instrument calibration devices, such as pressure (instrument) calibrator, temperature (humidity) degree ( Instrument) calibrator, process (instrument) calibrator, etc., so as to realize the long-term work of the instrument calibration device in the industrial field environment, and is easy to carry. [0003] Based on the special requirements of the measurement and calibration industry, in order to ensure the accuracy of measurement data, the meter calibration device needs to have high and reliable timing accuracy. Therefore, the RTC of the field meter calib...

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Problems solved by technology

[0006] 1) The higher the crystal oscillator frequency of the RTC module, the greater the power consumption. The industrial field calibration device is limited by its application characteristics, and the RTC module itself does not use a particularly high-frequency crystal oscillator signal.

The industrial on-site calibration device using a low-frequency crystal oscillator, once the frequency offset of the lower-frequency crystal oscillator occurs, the actual timing accuracy may be affected. Calibrating it with an external crystal oscillator as an external standard clock will increase the calibration cost and calibration complexity;

[0007] 2) The on-site working environment changes complexly. The same on-site instrument calibration device may be used in different environments in a short period of time, or the same on-site working environment may undergo large changes in temperature and humidity in a short period of time, or , there are many strong interference factors in the harsh on-site working environment, or there is a large deviation between the on-site working environment and the calibration environment

The above problems will cause the RTC of the industrial field instrument calibration device to be calibrated frequently. However, the existing technology is not suitable for carrying the external standard clock and the field instrument calibration device.

[0008] 3) Perform RTC clock calibration through the time obtained by GPS or relying on the time of the server. When the GPS signal is poor or the client cannot establish a connection with the server, the client is offline and cannot complete the RTC clock calibration

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