Campbell Scientific CR6 CR6 Measurement and Control System - Page 150
OpenInterval, DataTable, Average, Read More
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Section 7. Installation Typically, time-series data (averages, totals, maxima, etc.), that are output to a data table based on an interval, only include measurements from the current interval. After each data-output interval, the memory that contains the measurements for the time-series data are cleared. If a data-output interval is missed (because all criteria are not met for output to occur), the memory is cleared the next time the data table is called. If the OpenInterval instruction is contained in the DataTable() declaration, the memory is not cleared. This results in all measurements being included in the time-series data since the last time data were stored (even though the data may span multiple data-output intervals). Note Array-based dataloggers, such as CR10X and CR23X, use open intervals exclusively. Data-Output Processing Instructions Data-storage processing instructions (aka, "output processing" instructions) determine what data are stored in a data table. When a data table is called in the CRBasic program, data-storage processing instructions process variables holding 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 Definition and Use of a Data Table (p. 146), 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. 591)). Read More See Data Types (p. 137) 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. 151) and CRBasic example Using NAN to Filter Data (p. 480) 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 TrigVar and DisableVar (p. 195)- Controlling Data Output and Output Processing (p. 195) and Measurements and NAN (p. 478) discuss the use of 150