Errors caused by repeated extraction of differential pressure flowmeters

9.4 Errors introduced by repeated square extraction of differential pressure flowmeters Differential pressure flowmeters always have a square root operation, but if the differential pressure transmitter has squared off, open it again in the secondary flow meter. Square, it will produce a considerable error. Table 9.2 lists the comparison table of theoretical output values u200bu200bafter repeated prescriptions at each typical test point. Table 9.2 Theoretical output after repeated square rooting in comparison with 9.4 Errors introduced by differential pressure flowmeter repeated root square rooting Differential pressure flowmeter always has a square root operation, but if the differential pressure transmitter is squared off , If you open the square again in the second flow meter, a considerable error will occur. Table 9.2 lists the comparison table of theoretical output values u200bu200bafter repeated prescriptions at each typical test point. Table 9.2 Theoretical output comparison table after repeated square roots differential pressure value/% flow value after square root/% output value after repeated root square/% differential pressure value/% flow value after square root/% after repeated square root The output value/% differential pressure value/% flow value after square root/% output value after repeated square root/% 01490102030031.6244.7254.77162536494050607063.2570.7177.4683.676481100809010089.4494.87100 Repeated opening errors generally occur in differential pressure transmitters. In the system of prescribing function, it is caused by negligence. Generally, it is checked when there is a serious problem in the material balance calculation and the flow rate indication is suspected to be too high, and finally corrected. The effective ways to avoid repeated prescription errors are as follows. ① Update understanding. Many old instrument personnel's understanding of the function of the differential pressure transmitter habitually stays on the 'differential pressure transmission②Strengthen the management of basic data. The basic information includes not only the secondary meter verification sheet, but also the configuration data record sheet of the secondary meter and the transmitter verification sheet. ③When configuring, emphasize the operation according to the data record sheet to avoid impromptu operation. And add the password after the configuration is completed and the record sheet is correct to prevent random changes