Count Analysis Object (Counting Procedures Option)
You can use this analysis object to count a signal with some of the procedures described in the German DIN 45667 standard. You can choose between sampling, maximum value and time-at-level count. All of the other procedures described in DIN 45667 are covered by Rainflow Count.
Class Division
The counting is based on the division of the value range of the load-time function (source data set) into discrete classes. Various procedures are available to help you create this division. Essentially, the location of the class limits is specified in all of the procedures. The procedures only differ in the choice of parameters that you have to specify in order to set the class limits. The classes are formed as open-top intervals from the class limits specified, i.e. the lower limit is included in the class in each case. An exception is the top class, which also includes the top limit. Any values that lie above the top class or below the bottom class are not counted! Selecting a suitable Class division must be carefully planned, since only results that have been determined using the same class division can be directly compared.
Procedure
The three procedures can be differentiated by the way they function in counting and in the result.
•For the sampling count procedure every nth value is taken from the source data set and registered in its class. For n equals 1, this corresponds to the histogram function. This function, however, works with open marginal classes, unlike the counting procedure.
•For the maximum value count procedure, the highest of each n values from the source data set is counted in its class. For n equals 1, the maximum value count and the sampling count procedure both provide the same result.
•For the time-at-level count the time that the signal dwells in the respective classes is determined. For an equidistantly sampled signal, this corresponds to the absolute frequency in a class multiplied by the sampling interval. You cannot, however, use the time-at-level count for non-equidistantly sampled signals.
•For the mean value count procedure, the arithmetic mean value of the values falling in a class is calculated for each class. The procedure does not work with open marginal classes, i.e. values outside the classes are ignored.
Frequency
You can specify whether you would like to determine absolute, relative or percentage frequencies. The sum of the absolute frequency is always equal to the number of measured values counted. This can be lower than the number of values in the source data set! For relative and percentage frequencies, normalization is to one or one hundred, i.e. the sum of the frequencies results in one or one hundred. If the signal contains void values, this is accounted for when the normalization takes place.
References
[1] DIN 45667 (1970). Klassierverfahren für das Erfassen regelloser Schwingungen (Counting procedures for determining random oscillations). Beuth Verlag
FPScript Functions Used
See Also
Compound Count Analysis Object
Rainflow Count Analysis Object