PLC analog quantity automatic calibration method and system

The invention discloses a PLC analog quantity automatic calibration method and system, and the method comprises the steps: obtaining the information of a to-be-calibrated module through scanning equipment, uploading the information to an upper computer, recognizing the information of the to-be-calibrated module through the upper computer, generating a popup window, and entering a calibration mode; the module platform uploads to-be-calibrated module data information to the upper computer through a serial port for self-checking, after self-checking is completed, the upper computer automatically selects a calibration mode according to the to-be-calibrated module data information and obtains a standard signal source and to-be-calibrated module channel data, the standard signal source serves as a reference value xi, and the to-be-calibrated module channel data is obtained; and taking the channel data of the module to be calibrated as an actual value yi, and obtaining a calibration coefficient and a calibration val