Span Specified as a ratio, for example 1:50. Ratio of the smallest flow rate that can be adjusted to the nominal flow rate. Settling time Time required by the MFC to achieve 95 % of the difference between the old and new flow rate. Response time Time required by a MFM to adjust its display to 95 % of the new value after a sudden change in flow rate from Q Accuracy The most realistic is a combined figure in ± x % of rate ± y % of full scale value. Repeatability Figure in ± x % of full scale value. Repeatability, or reproducibilityas it is also called, is a measure of the distribution of the actual values that result from the repeated ad-justment of a reproduced set-point value, starting from a specific start- ing value. Linearity Figure in ± x % of full scale value. Maximum deviation of the signaled actual value from the set-point val-ue, if this is passed slowly over the entire range. Sensitivity Figure in ± x % of full scale value. The smallest change in set-point value that results in a reproducible change in the flow rate.
1 to Q
2 .
MFM

(t

95

)Q =Q

1

+ 0.95 (Q

2

- Q

1

)

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