1. A monitoring system for monitoring operation of dynamic plant apparatus comprising: a plurality of sensors measuring dynamically varying operating parameters of the monitored dynamic plant apparatus and for generating electrical parameter signals indicative of the measured operating parameters; electronic processing means for processing the electrical parameter signals and which is capable of thereby producing a plurality of different fault signals each of which respectively indicates that the monitored dynamic plant apparatus has a respective one of a plurality of faults; display means for displaying fault information to a user of the monitoring system, the display means being controlled by the fault signals produced by the electronic processing means; wherein: the electronic processing means compares the values of at least some of the measured parameter signals each with respective predefined limit values stored in memory by the electronic processing means and when the comparison shows that the value of a measured parameter signal is outside the respective limit value the electronic processing means produces a respective basic fault token signal, characterised in that: the electronic processing means has storage means for storing electrical signals which operates in a clocked manner and stores the basic fault token signals; the storage means has a plurality of different storage sites, each storage site having a plurality of storage locations for a different predetermined variety of basic fault token signals; and when all storage locations of a storage site are filled by basic fault token signals produced in a prespecified clocked interval then the electronic processing means produces a high level fault signal, each storage site having an associated high level fault signal, the high level fault signal causing the display means to display a fault message.