Specifications

Section 6. Data Table Declarations and Output Processing Instructions
Parameter
& Data Type
Enter
DataType
A code to select the data storage format.
Constant
Code Data Format
IEEE4 IEEE 4 byte floating point
FP2 Campbell Scientific 2 byte floating point
DisableVar
Constant,
Variable, or
Expression
A non-zero value will disable intermediate processing. Normally 0 is entered so all inputs
are processed. For example, in the Average instruction, when the disable variable is ≠0
the current input is not included in the average. The average that is eventually stored is
the average of the inputs that occurred while the disable variable was 0.
Value Result
0 Process current input
≠ 0
Do not process current input
Covariance (DimX, XVal, DataType, DisableVar, NumOfCov)
Calculates the covariance of values in an array over time. The Covariance of
and is calculated as:
X Y
()
Cov X Y
XY
n
XY
n
ii
i
n
i
i
n
i
i
n
(,)=
⋅
−
⋅
==
∑∑
11
2
=
∑
1
where
is the number of values processed over the output interval and
and
Y
are the individual values of and
Y
.
n
X
i
i
X
Parameter&
Data Type
Enter
DimX
Constant
The number of elements in the array to include in the covariance calculations
XVal
Variable
Array
The variable array that contains the values from which to calculate the
covariances. If the covariance calculations are to start at some element of the
array later than the first, be sure to include the element number in the source
(e.g., X(3)).
DataType
A code to select the data storage format.
Constant
Alpha Code Data Format
IEEE4 IEEE 4 byte floating point
FP2 Campbell Scientific 2 byte floating point
DisableVar
Constant,
A non-zero value will disable intermediate processing. When the disable variable is ≠0
the current input is not included in the Covariance.
Variable, or
Value Result
Expression 0 Process current input
≠ 0
Do not process current input
NumOfCov
Constant
The number of covariances to calculate. The maximum number of covariances
is Z/2*(Z+1). Where Z= NumVals. If X(1) is the first specified element of the
source array, the covariances are calculated and output in the following
sequence: X_Cov(1)…X_Cov(Z/2*(Z+1)) = Cov[X(1),X(1)], Cov[X(1),X(2)],
Cov[X(1),X(3)], … Cov[X(1),X(Z)], Cov[X(2),X(2)], Cov[X(2),X(3)], …
Cov[X(2),X(Z)], … Cov[X(Z),X(Z)]. The first “NumCov” of these possible
covariances are output.
6-13