Campbell Scientific PC208 Datalogger Support Software - Manual (Page 60)

SECTION 4. SPLIT
4-6
Logical "and" and "or" statements can be used
when specifying the START condition (STOP
and COPY conditions also). A logical "and"
statement means that all conditions must be
true for the statement to be true. The logical
"or" statement means that if any of the
conditions are true then the statement is true.
SPLIT allows up to 6 "or" statements with up to
3 "and" statements per "or". A simple logical
"and" example follows:
2[189]and3[1200]
Element 2 must equal 189 and element 3 must
equal 1200.
A range can be specified for vali by putting a ".."
between the lower and upper limit. For
example:
2[189]and7[200..275]
In this example two conditions must be satisfied
to START processing data. First, the Julian day
must be 189 and second the wind direction
must be between 200 to 275 degrees, inclusive.
The time sync function is useful when data are
missing from files or several files of data need
to be merged together. The files are
synchronized according to time. This function
syncs according to day, hrmn (hour-minute),
and/or seconds. The syntax used to identify the
time elements is:
e
i
[day]:e
i
[hrmn]:e
i
[seconds]
Referring to Table 4.3-1, to identify the day of
year, type '2[189]::', for hrmn type ':3[1200]:',
and seconds are expressed as '::4[5]'. A single
colon is assumed to be between day and hrmn
(e.g., 2[189]: means day, :3[1200] means hours,
and 2[189]:3[1200] means day and hour-
minute). When the time sync function is used,
a time interval must be specified in the COPY
parameter (Section 4.3.5). If no time interval is
specified in the Copy parameter then the time
specified in the START condition becomes
simply a starting time with no time
synchronization. The starting time specified
must actually be found in the input file before
the STARTing condition is satisfied (e.g., if the
input file starts at 11AM and 10AM is entered
for the starting time, with no day specified,
SPLIT will skip over arrays until it reaches 10
the next day).
Time elements can be identified without
specifying a starting time (e.g., '2:3'). When no
starting time is specified SPLIT assumes the
starting time to be 0 and inserts carriage return
line feeds (CRLF) at the start of the OUTPUT
file. The number of CRLFs equals the time
between 0 and the time of the first array
selected, divided by the interval specified in the
COPY (Section 4.3.5) parameter.
When time synching, if multiple input files are
given STARTing times, SPLIT starts the
OUTPUT at the earliest specified starting time.
Blanks or /[comment] are inserted for values
from other input files until their starting time is
reached.
Included in the time sync function is the ability to
start relative to the current PC TIME (computer
time). This feature allows a .PAR file to be run
on different data without changing the START
conditions provided the INPUT data is collected
at a fixed frequency and SPLIT is run at a fixed
frequency. For example, assume that TELCOM
is used in the unattended mode (see Script
files, Section 5.3) to collect data which is
automatically appended to an archive file.
SPLIT is run within the script file. In this case
the frequency of data collection and data
reduction are 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 STARTing 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.
:3[-60,5] tells SPLIT to start at the closest 5
minute interval that is less than the PC time
minus 60 minutes. If the PC time is 1404,
SPLIT calculates 1304 and looks for hour 1300
to start reading.
2[-3]:3[-120,60] means find the closest 60
minute interval that is less than the PC time
minus 3 days and 2 hours. If the PC time is 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] means 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,