Campbell Scientific CR9000X Measurement and Control System - Manual (Page 149)

Section 4. CRBasic – Native Language Programming
tables can be created by the program. The data tables may store individual
measurements, individual calculated values, or summary data such as averages,
maxima, or minima to data tables.
Each data table has overhead information, referred to as "Table Definitions",
that becomes part of the ASCII file header when data are downloaded to a PC.
Overhead information includes:
• table format
• datalogger type, serial number, and operating system version,
• name and signature of the CRBASIC program running in the datalogger
• name of the data table (limited to 8 characters)
• alphanumeric field names to attach at the head of data columns
• user defined units for the output fields
• output processing information (max, min, sample, etc.)
See Section 2.4 Data Format on Computer for more information.
Data storage follows a fixed structure in the CR9000X in order to optimize the
time and space required. Data are stored in tables such as shown in Table
4.2.8-1.
Table 4.2.8-1 Data Table Example
TOA5 StnName CR9000X Serial# OSVersion ProgName ProgSignature Table1
TIMESTAMP RECORD RefTemp_Avg TC_Avg(1) TC_Avg(2) TC_Avg(3) TC_Avg(4) TC_Avg(5) TC_Avg(6)
TS RN DegC DegC DegC degC degC degC degC
Avg Avg Avg Avg Avg Avg Avg
1995-02-16 15:15:04.61 278822 31.08 24.23 25.12 26.8 24.14 24.47 23.76
1995-02-16 15:15:04.62 278823 31.07 24.23 25.13 26.82 24.15 24.45 23.8
1995-02-16 15:15:04.63 278824 31.07 24.2 25.09 26.8 24.11 24.45 23.75
1995-02-16 15:15:04.64 278825 31.07 24.21 25.1 26.77 24.13 24.39 23.76
The user's program determines the values that are stored and their sequence.
The CR9000X automatically assigns names to each field in the data table. In
the above table, TIMESTAMP, RECORD, RefTemp_Avg, and TC_Avg(1) are
fieldnames. The fieldnames are a combination of the variable name (or alias if
one exists) and an underscore and three letter mnemonic (_avg, _smp, _std) for
the processing instruction that output the data. Alternatively, the FieldNames
instruction can be used to override the default names.
See Section 4.3 Program Access to Data Tables for a list of 3 letter
mnemonics.
The data table header also has a row that lists units for the output values. The
units must be declared for the CR9000X to fill this row out (e.g., Units
RefTemp = DegC). The units are optional and are strictly for the user's
documentation; the CR9000X makes no checks on their accuracy.
The table depicted in Table 4.2.8-1 is the result of the data table construct
shown in Example 4.2.8-1.
EXAMPLE 4.2.8-1: CRBasic Code: Data Table
DataTable (Table1,1,2000)
DataInterval(0,10,msec,10)
Average(1,RefTemp,fp2,0)
Average(6,TC(1),fp2,0)
EndTable
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