Campbell CR3000 Micrologger, Руководство оператора

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Section 8. Operation
453
Record Element 1 – Timestamp
Data without timestamps are usually meaningless. Nevertheless, the
TableFile() instruction optionally includes timestamps in some formats.
Record Element 2 – Record Number
Record numbers are optionally provided in some formats as a means to
ensure data integrity and provide an up-count data field for graphing
operations. The maximum record number is &hffffffff (a 32-bit number),
then the record number sequence restarts at zero. The CR3000 reports back
to the datalogger support software 31 bits, or a maximum of &h7fffffff, then
it restarts at 0. For example, if the record number increments once a second,
restart at zero will occur about once every 68 years (yes, years).
8.8.3 Memory Cards and Record Numbers
Related Topics:
• Memory Card (CRD: Drive) — Overview
(p. 81)
• Memory Card (CRD: Drive) — Details
(p. 447)
• Memory Cards and Record Numbers
(p. 453)
• Data Output: Writing High-Frequency Data to Memory Cards
(p. 217)
• File System Errors
(p. 464)
• Data Storage Devices — List
(p. 613)
• Data File Format Examples
(p. 450)
• Data Storage Drives Table
(p. 445)
The number of records in a data table when CardOut() or TableFile() with
Option 64 is used in a data-table declaration is governed by these rules:
1. Memory cards (CRD: drive) and internal memory (CPU) keep copies of data
tables in binary TOB3 format. Collectible numbers of records for both CRD:
and CPU are reported in DataRecordSize entries in the Status table.
2. In the table definitions advertised to datalogger support software
(p. 90),
the
CR3000 advertises the greater of the number of records recorded in the Status
table, if the tables are not fill-and-stop.
3. If either data area is flagged for fill-and-stop, then whichever area stops first
causes all final-data storage to stop, even if there is more space allocated in the
non-stopped area, and so limiting the number of records to the minimum of the
two areas if both are set for fill-and-stop.
4. When CardOut() or TableFile() with Option 64 is present, whether or not a
card is installed, the CPU data-table space is allocated a minimum of about 5
KB so that there is at least a minimum buffer space for storing the data to
CRD: (which occurs in the background when the CR3000 has a chance to
copy data onto the card). So, for example, a data table consisting of one four-
byte sample, not interval driven, 20 bytes per record, including the 16 byte
TOB3 header/footer, 258 records are allocated for the internal memory for any
program that specifies less than 258 records (again only in the case that
CardOut() or TableFile() with Option 64 is present). Programs that specify
more than 258 records report what the user specified with no minimum.