<Q> How should we consider the overall accuracy when using multiple measuring instruments?
<A> Typically, to perform the desired measurement, it is necessary to combine multiple measuring instruments such as detectors, their converters, and indicators. For instruments used in pairs, such as detectors and their converters, the overall accuracy is indicated. However, when using a combination of independent measuring instruments, there is no specific definition for the overall accuracy of multiple errors. However, based on error theory, it is generally taken as the mean square of the accuracy of each instrument.
If we have three devices to combine, and the accuracy of each individual device is a%, b%, and c%, then the overall accuracy A can be calculated as follows:
A = √(a^2 + b^2 + c^2)
Here, the expression in parentheses represents what is inside the square root, and ^2 represents squaring.
For example, if a=1%, b=2%, and c=3%, the combined result in overall accuracy A=3.74%.
(Excerpt from the email newsletter published on October 25, 2001)
