Campbell Scientific CR9000X Measurement and Control System - Manual (Page 188)

Section 6. Data Table Declarations and Output Processing Instructions
OpenInterval
When the DataInterval instruction is included in a data table, the CR9000X
uses only values from within an interval for time series processing (e.g.,
average, maximum, minimum, etc.). When data are output every interval, the
output processing instructions reset each time output occurs. To ensure that
data from previous intervals are not included in a processed output, processing
is reset any time an output interval is skipped. (An interval could be skipped
because the table was not called or another trigger condition was not met.) The
CR9000X resets the processing the next time that the table is called after an
output interval is skipped. If this next call to the table is on a scheduled
interval, it will not output. Output will resume on the next interval. (If Sample
is the only output processing instruction in the table, data will be output any
time the table is called on the interval because sampling uses only the current
value and involves no processing.)
OpenInterval is used to modify an interval driven table so that time series
processing in the table will include all values input since the last time the table
output data. Data will be output whenever the table is called on the output
interval (provided the other trigger conditions are met), regardless of whether or
not output occurred on the previous interval.
OpenInterval Example:
In the following example, 5 thermocouples are measured every 500
milliseconds. Every 10 seconds, while Flag(1) is true, the averages of the
reference and thermocouple temperatures are output. The user can toggle
Flag(1) to enable or disable the output. Without the OpenInterval Instruction,
the first averages output after Flag(1) is set high would include only the
measurements within the previous 10-second interval. This is the default and is
what most users desire. With the OpenInterval in the program (remove the
initial single quote (‘) to uncomment the instruction) all the measurements made
while the flag was low will be included in the first averages output after the flag
is set high.
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