Signal_Statistics: Calculating Maximum, Minimum, Average and Variance

 

Signal_Statistics Function Block

Pin Diagram

This figure shows the pin diagram of the Signal_Statistics function block:

 

 

Functional Description

This function block calculates the maximum, minimum, average and variance of a series of input values.

This function block considers the input value in each controller scan cycle as a Sample.

Minimum Value

Minimum Output value is the value which is minimum amongst all the recorded samples.

Maximum value

Maximum Output value is the value which is maximum amongst all the recorded samples.

Average Value

The average value is equal to the sum of the observations (samples) divided by the number of observations (samples).

 

 

Where:

on = Number of samples recorded

oXn = Input samples

o = Calculated output

Variance Value

The variance is equal to the mean of the squares of samples minus the square of the mean (Average output value).

 

Where:

on = Number of samples recorded

oXn = Input samples

o  = Calculated output

Example

oStatistics (Enable: = TRUE, Input: = 1, 2

oMinimum Output =1

oMaximum Output = 2

oAverage = (1 + 2) / 2 = 1.5

oVariance = ((1 * 1 + 2 * 2) / 2) - (1.5 * 1.5) = 2.5 - 2.25 = 0.25

Input Pin Description

This table describes the input pins of the Signal_Statistics function block:

Output Pin Description

This table describes the output pins of the Signal_Statistics function block: