This paper describes the mathematics behind CUSUM control charts.
An introduction to CUSUM charts is found in (Madsen 1998).CUSUM
charts are well suited for checking a measuring system in
operation for any departure from some target or specified values.
In general they can be used for:- detecting a drift (or shift in
the level) of the measuring system, and- detecting a change of the
precision of the measuring system.In both cases the CUSUM
procedure contains methods for estimating the shift such that
maintenance (e.g. recalibration) can take place.The CUSUM
procedure is described in ISO/CD 7871 from CEN-TC 69. However the
presentation in ISO/CD 7871 concentrates on the level, whereas
CUSUM charts for detecting changes in the precision are not
discussed.This document outlines the theory of CUSUM control
charts, and both CUSUM procedures for detecting a drift as well as
CUSUM procedures for detecting a shift in the precision are
outlined. In the later case a simple example is given.
|Number of pages||23|
|Publication status||Published - 1998|