METHOD AND DEVICE FOR ADJUSTING ELECTROMAGNETIC FLOWMETER

PURPOSE:To make it possible to perform easy adjusting work without stopping flow of fluid, by alternately switching and connecting a reference converter and an other converter to the oscillator of an electromagnetic flowmeter, and aligning the flow rates to the span of the reference converter by using two flow rates. CONSTITUTION:The output of a reference converter 2 becomes ym=Ka.u+b and it is expressed by a characteristic curve I . The output of a converter 3 becomes yt=Kt.u (where Ka and Kt are constants of proportion, (u) is a flow rate, and (b) is a zero point). A flow rate u1 is flowed, the span of the converter 3 is adjusted and aligned with the output indication value of the converter 2. The relationship between the outputs ym1 and yt1 of the converters 2 and 3 becomes ym1=Ka.u1+b=yt1=Kt.u1. The indication of the converter 3 becomes a characteristic curve II. When the flow rate is made to be u2, the output indications ym2 and yt2 of the converters 2 and 3 become ym2=Ka.u2+b and yt2=Kt.u2. The difference becomes DELTAy=b(-u2/u1+1), and b=yt1 (tm2-yt2)/(yt1-yt2) is obtained. When the flow rate is returned to u1 and the span of the converter 3 is shifted by (b) and adjusted, a characteristic curve III is obtained, and a calibrated indication output is obtained.