2-24
IM WT310E-01EN
Explanation
Averaging
You can take exponential or moving averages of the numeric data. The averaging function is useful
when because of large changes in the power or load or a low input signal frequency, the numeric
display fluctuates and is difficult to read.
Measurement Functions That Are Averaged
The measurement functions that are directly averaged are indicated below. Other functions that use
these functions in their computation are also affected by averaging.
• U, I, P, S, and Q
• λ, Φ, Cf U, and Cf I are computed using the averaged values of Urms, Irms, P, S, and Q.
Measurement Functions That Are Not Averaged
Measurement functions that would lose their meaning if they were averaged, such as the peak values
(Upk and Ipk), are not averaged.
• fU, fI, U+pk, U–pk, I+pk, I–pk, P+pk, P−pk, Time, WP, WP+, WP–, q, q+, and q-
Averaging Type
You can use exponential (EP) or moving (Lin) averages. The default setting is Lin.
Exponential Averaging (EP)
With the specified attenuation constant, the numeric data is exponentially averaged according to the
equation below.
D
n
=
(M
n
−
D
n
−
1
)
K
D
n
−
1
+
D
n
: Displayed value that has been exponentially averaged n times. (The first displayed value, D
1
, is
equal to M
1
.)
D
n–1
: Displayed value that has been exponentially averaged n–1 times.
M
n
: Numeric data at the nth time
K: Attenuation constant
Moving Average (Lin)
The specified average count is used to compute linear averages according to the equation below.
D
n
=
M
n
−
(m
−
1)
+ • • • M
n
−
2
+ M
n
−
1
+ M
n
m
D
n
: Displayed value of the linear average of a total of m items of numeric data from the n–(m–1)
th
to
the n
th
time
M
n–(m–1)
: Numeric data at the n–(m–1)
th
time
………………………………………………
………………………………………………
M
n–2
: Numeric data at the n–2
th
time
M
n-1
: Numeric data at the n–1
th
time
M
n
: Numeric data at the n
th
time
m: Average count
2.11 Setting Averaging
