Eaton easyE4

6. Function blocks
6.1 Manufacturer function blocks
Other
How average values are calculated in the AV function block
For these examples, the maximum number of values used to calculate the average
value (NO) will be 24.
Moreover, the examples use the sample temperature values in the table below and
assume that they were (multiplied by 100) present and measured at function block
input I1.
One-time mode
In one-time mode, the moving average is calculated using the following formula:

One-time mode average value CMA(n) = ROUND [ CMA
n-1
+ (I1
n
– CMA
n-1
)/(n+1) ]

CMA(n) = Currently calculated simple moving average
n = 1…NO
I1
n
= Value at function block input I1; e.g., temperature value
Continuous operation
In continuous mode, the smoothing factor is calculated first.

Smoothing factor SF = 2 / (NO+1)


SF = Smoothing factor; value between 0
and 1
NO = Maximum number of values to be
included in the calculation
The average value is then calculated using the formula below:

Continuous operation average value EMA(n) = ROUND [ EMA
n-1
+SF* ( I1
n
– EMA
n-1
) ]

EMA(n) = Currently calculated exponential moving average
n = 1…NO
SF = Smoothing factor; value between 0 and 1
I1
n
= Value at function block input I1; e.g., temperature value
easyE402/24 MN050009ENEaton.com
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