Section 7. Installation
current inputs or calculations. If trigger conditions are true, for example if the
data-output interval has expired, processed values are stored into the data table. In
CRBasic example Declaration and Use of a Data Table
(p. 143), three averages are
stored.
Consider the Average() instruction as an example data-storage processing
instruction. Average() stores the average of a variable over the data-output
interval. Its parameters are:
• Reps — number of sequential elements in the variable array for which
averages are calculated. Reps is set to 1 to average PTemp, and set to 2
to average two thermocouple temperatures, both of which reside in the
variable array Temp_C.
• Source — variable array to average. Variable arrays PTemp_C (an array
of 1) and Temp_C() (an array of 2) are used.
• DataType — Data type for the stored average (the example uses data
type FP2
(p. 557)).
Read More See Declaring Data Types
(p. 127) for more information on available
data types.
• DisableVar — controls whether a measurement or value is included in
an output processing function. A measurement or value is not included
if DisableVar is true (≠ 0). For example, if the disable variable in an
Average() instruction is true, the current value will not be included in
the average. CRBasic example Use of the Disable Variable
(p. 147) and
CRBasic example Using NAN to Filter Data
(p. 469) show how DisableVar
can be used to exclude values from an averaging process. In these
examples, DisableVar is controlled by Flag1. When Flag1 is high, or
True, DisableVar is True. When it is False, DisableVar is False.
When False is entered as the argument for DisableVar, all readings are
included in the average. The average of variable Oscillator does not
include samples occurring when Flag1 is high (True), which results in
an average of 2; when Flag1 is low or False (all samples used), the
average is 1.5.
Read More Data Output: Triggers and Omitting Samples
(p. 192) and
Measurements and NAN (p. 466) discuss the use of TrigVar and DisableVar in
special applications.
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