【Daily Question 20090214】 A calculation problem
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Given: A flow measurement system consists of a 0.75 class standard nozzle, a 0.25 class differential pressure transmitter, a 1.0 class square rooter, and a 0.5 class display instrument. Find: 1. The accuracy class of this measurement system； 2. If the flow measurement range is 300–1250 T/h, determine the measurement error of this system. ryu=(0.752+0.252+1.02+0.52)1/2=1.369 δ= ryu%A=1.369%X(1250-300)=13.01T/h Last edited by liwei2002 on 2009-2-17 08:27]
Solution: ryu = (0.752 + 0.252 + 1.02 + 0.52)1/2 = 1.369; δ = ryu/%A = 1.369% × X(1250 – 300) = 13.01 T/h
Why does it always end in a 2? Why is the average accuracy multiplied by 1/2? Why not use the maximum range value to calculate the error? This post was last edited by chmyh on 2009-2-15 09:50]
In the calculation formula, it’s not just a factor of 2 added at the end; rather, it’s the square of 2 and the square root of 1/2. Check my answer to the original question. The error is an error of the range, not an error of the maximum measurement limit; therefore, it is a difference.