Generalized consistency checking of multivariable redundant measurements and common-mode failure detection

The limitations of the single-variable consistency checking algorithm for validating redundant measurements are remedied by extending it to multiple process signals. The redundant measurements of each variable in a subsystem are combined with an estimate of the variable using prediction models. A complex logic algorithm has been developed to perform simultaneous consistency checking of all variables under consideration. The new algorithm has been implemented in a general purpose PC and in a VAX workstation. Applications to sensor failure monitoring and to detect and isolate common-mode sensor failures are studied. 3 refs., 21 figs