Method and apparatus for automatic abnormal events monitor in operating plants

In an operating plant having significant background noise in time dependent fluctuating signals derived from sensors placed at selected points for continually monitoring the operating conditions of system components, apparatus for scanning in real-time separate signal conditioning channels, one for each of said signals, to find potential malfunctions, draw conclusions as to their severity and indicating to an operator what action to take comprising a computer and including:

• computer controlled means for automatically selecting each channel in sequence for power spectrum density analysis;
• computer controlled means for automatically processing the signal of each channel selected to produce power spectral data at predetermined frequencies over a predetermined frequency range as a simple Fourier transform;
• means within said computer for automatically comparing said power spectral density data of each channel with predetermined sets of frequency dependent limits, each set consisting of at least two limits, one for a condition requiring caution, and another for an alarm condition requiring more direct action by the operator;
• and
• computer controlled means for automatically indicating to the operator the condition of plant components associated with each channel and the action to be taken as a function of which set of limits and which limit of the set is exceeded by said power spectral density data.