Online monitoring method for metering performance of diaphragm gas meter

An online monitoring method for metering performance of a diaphragm gas meter, comprising:

• providing a magnetic turntable in an electromechanical conversion device, the magnetic turntable being segmented into a plurality of segments;
• recording and analyzing motion information of each of the plurality of segments;
• and
• determining metering errors of the diaphragm gas meter, internal leakage judgment, external leakage judgment and safety judgment for a constant flow rate based on qualitative and quantitative judgement using the analyzed motion information of the each of the plurality of segments, wherein
• the external leakage judgement is performed by setting gas consumption and gas utilization time for a constant flow rate, the gas consumption and the gas utilization time for the constant flow rage being set by the following steps:
• Step 1:
• for a relatively constant flow rate more than or equal to a first flow value and less than or equal to a second flow value, setting that one-time gas consumption is not allowed to exceed a first gas consumption value;
• and setting values of the first flow value, the second flow value and the first gas consumption value according to a space volume of a relatively enclosed gas utilization region, gas utilization characteristics of gas equipment and an explosion lower limit of methane;
• Step 2:
• for a relatively constant flow rate higher than the second flow value and lower than a maximum flow of the gas meter, determining according to registration information of the gas equipment that the one-time gas consumption is not allowed to exceed a second gas consumption value and the duration is not allowed to exceed a discharge period;
• and
• Step 3:
• for a flow between consequent generation of two period signals within 6 hours and the first flow value, determining occurrence of leakage.