ABB 800xA Operation page 102

Performance indices
Sl.No Name
32. Valve sizing Index
33. Non-linearity 1st
Index
34. Non-linearity 2nd
Index
35. Non-Gaussianity
Index
36. Oscillation
Symmetry Index
37. Estimated process
time-delay
102
Section 8 Control Loop Asset Monitor (CLAM)
Table 9. Indices used in CLAM
Description
Quantifies the amount of time that the controller
output is within normal operating range (10-
90%). [0...100%] Nominally the controller
should be within normal range > 50 % of time,
i.e. index value should be larger than 50 %.
Index detecting the amount of nonlinearity
within a signal using higher-order statistics. The
result is dimensionless [0...Inf] and the signal is
considered to be linear if the index is below 1.
Index detecting the amount of nonlinearity
within a signal by bispectrum analyzing using
higher order statistics. Dimensionless result
[0...Inf], where a signal is considered to be
linear if index below 0.15.
Index quantifying the amount of non-
Gaussianity within a signal based on
bispectrum analysis using higher-order
statistics. The result is a dimensionless real
number where Non-Gaussian signals should be
below 0.01.
Index describing the symmetry of the oscillation
half-periods. This is performed by checking for
if area under first half of the half-cycle is equal
to the area under the second part of the half-
cycle. Result is a value in the interval [0...100
%] where an oscillation is considered
symmetric for values greater than 40 %.
Index estimating the process time delay that
can be used for tuning etc. In order to estimate
the delay the data needs to be sufficiently
exciting.
Index class
Valve
Nonlinearity
Nonlinearity
Nonlinearity
Nonlinearity
Property
3BUA000150-600