A SELECTIVE MORITORING SYSTEM

A system is monitored by an operator choosing a part thereof having a number of items of equipment; determining the values of parameters of components forming the equipment items included in the chosen part of the system; deciding from the values if the parameters are abnormal; determining in which of a plurality of categories each parameter falls and grouping together those parameters that are abnormal in each category for each equipment item; selecting, by an operator, certain types of the equipment items and certain of the categories; and displaying all of the equipment items of the chosen part of the system and all of the categories having abnormal parameters in a graphical manner, with the selected types of equipment items and the selected categories for those selected types of equipment items being displayed in a normal manner and those that have not been selected being "greyed-out". The operator may also select certain operational characteristics, with only those equipment item types having those characteristics being normally displayed and the others also being "greyed-out".