Specifications

Section 8. Processing and Math Instructions
8-9
Parameter
& Data Type
Enter
Dest
Variable or
Array
The Variable in which to store the results of the instruction. When multiple
covariances are calculated, the results are stored in an array with the variable
name. An array must be dimensioned to at least the value of NumOfCov.
NumOfCov
Constant
The number of covariances to be calculated. If four data sets are to be
compared against a fifth set, this would be set to four.
SizeOfSets
Constant
The number of values in the data sets for the covariance calculations.
CoreSet
Array
The array that holds the core data set. The covariance of core data with each
of the other sets is calculated independently. The data need to be
consecutive in the array. If the first data value is not the first point of the
array, the first point of the data set must be specified in this parameter.
DataSets
Array
The array that contains the data set(s) for calculating the covariance with the
CoreSet. When multiple covariances are calculated, the data sets have to be
loaded consecutively into one array. The array must be dimensioned to at
least the value of NumOfCov multiplied by SizeOfSets. For example, if
each set of data has 100 elements (SizeOfSets), and there are 4 covariances
(NumOfCov) to be calculated, then the DatArray needs to be dimensioned to
4 x 100 = 400. If the first value of the first set is not the first point of the
array, the first point of the data set must be specified in this parameter.
CSGN (Number)
Changes the sign of a number or variable.
This function will change the sign (+ or -) of a value. Typically, it is used in
the form of VariableA = CSGN(VariableB).
DewPoint (Dest, Temp, RH)
Parameter
& Data Type
Enter
Dest
Variable
The variable in which to store the dew point temperature (°C).
Temp
Variable
The variable that contains air temperature (°C).
RH
Variable
The variable that contains RH (%).
The dew point instruction calculates the dew point temperature from
previously measured values of RH and air temperature. While end results may
not be quite as accurate as those from a dedicated dew point sensor, they are
acceptable for a wide range of applications.
Calculating Dew Point
Measure the relative humidity (RH) and air temperature (T
a
; units °C) with the
appropriate instruction for the sensors you are using.