Campbell Scientific PC400 Datalogger Support Software - Manual (Page 63)

Section 5. Split
5.3.1.3.1 Starting Relative to PC Time
Split has the ability to start relative to the current PC TIME (computer time).
This feature allows a .PAR file to be run on new data files without changing
the Start Conditions, provided the Input Data File is collected at a fixed interval
and Split is run at a fixed interval. For example, the same PAR file could be
run every day to display the last 48 hours of data without changing the start
conditions. For example, using a table based data file:
Start Condition = 1:1[-1]:1[1200]:1:
In this instance, Split will begin processing data when the date for both files is
one less than the current date (1:1[-1]:1[1200]:1:)and the time is 1200 (1:1[-
1]:1[1200]:1:).
As an expanded example, assume that LoggerNet or PC400 is used to append
data to an archive file. SplitR is executed using a desktop shortcut. In this case
the frequency of data collection and data reduction is the same. Time values in
the data file (day, hrmn, sec.) are different each time the data are collected, but
by telling Split where to Start reading relative to the PC clock, the Start
Conditions do not need to be changed. To accommodate variations in the data
collection and reduction frequencies, an interval in minutes or seconds may be
specified as shown in the examples below.
2[-0]:3[-60,5] tells Split to start at a timestamp in the data that is between 55
and 65 minutes prior to the current PC time (the closest 5 minute interval of the
current day that is less than the PC time minus 60 minutes). If you are
processing data stored at the top of the hour and the PC time is 1404, Split
calculates 1304 and looks for hour 1300 to start reading.
2[-3]:3[-120,60] tells Split to find the closest 60 minute interval that is less
than the PC time minus 3 days and 2 hours. If the PC time is the day of year
159, hour 0017, Split will start reading on data output at 2200 hours on day
155.
2[-3]:3[-120]:4[20,5] tells Split to find the closest 5 second interval that is less
than the PC time minus 3 days, 2 hours and 20 seconds. If the PC time is 27
seconds after noon on day 30, Split will begin reading on data output at 1000
hours and 05 seconds on day 27.
Split can also begin processing a file on a particular month and day. Use the
syntax :E[Month%Day]::, where E is the element that contains the Julian Day,
and Month and Day are either constants or a value related to PC time. For
example:
:2[-1%1]:: tells Split to begin processing on the first day of the previous
month.
:2[-0%15]:: tells Split to begin processing on the fifteenth day of the
current month.
:2[5%1]:: tells Split to begin processing on May 1.
This function can be used in both the Start and Stop conditions. It provides a
simple way to create a monthly report. For additional information, refer also to
Section 5.3.1.15.2, Using Time Synchronization While Starting Relative to PC
Time.
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