Sensors detect machine parameters such as vibration, turning speed, and
temperature, and a local processor performs logic operations based on the
parameters and inference rules to produce fault information that is
reported to a system processor, which selectively uses the fault
information to control the plant machines. The inference rules include
rules for determining faults as to balance, alignment, bearing condition,
electrical condition, and cavitation. The inference rules are contained
in rules code that is separate from the analysis code that performs the
logical operations. Thus, the inference rules may be easily changed
without changing other code, such as the analysis code.