Interpreting the graphs that are produced by EngTrend is the key task in EngTrend.
There are some general principles which will aid your understanding of the diagnostic process. See EngTrend Diagnostic Paradigm.
By learning how different faults produce different effects in the graphical output, you can learn how to recognize different problems. In addition to this chapter, which covers some typical faults and what they look like graphically, there are diagnostic tools included with EngTrend that will help you diagnose the likely problem that your graphical output is showing. See Diagnostics for more detail on these tools.
Each of the sections of this chapter covers one typical fault and what it looks like graphically in EngTrend output.