8.10 Memory Cards and Record Numbers
Related Topics:
• Memory Card (CRD: Drive) — Overview (p. 89)
• Memory Card (CRD: Drive) — Details (p. 376)
• Memory Cards and Record Numbers (p. 466)
• Data Output: Writing High-Frequency Data to Memory Cards (p. 205)
• File-System Errors (p. 389)
• Data Storage Devices — List (p. 653)
• Data-File Format Examples (p. 379)
• Data Storage Drives Table (p. 373)
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. 95), the
CR1000 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 CR1000 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.
5. When CardOut() or TableFile() with Option 64 is used but the card is not
present, zero bytes are reported in the Status table.
6. In both the internal memory and memory card data-table spaces, about 2 KB of
extra space is allocated (about 100 extra records in the above example) so that
for the ring memory the possibility is minimized that new data will overwrite
the oldest data when datalogger support software
(p. 95) tries to collect the
oldest data at the same time. These extra records are not reported in the
Status table and are not reported to the datalogger support software and
therefore cannot be collected.
7. If the CardOut() or TableFile() with Option 64 instruction is set for fill-and-
stop, all the space reserved for records on the card is recorded before the
writing of final-data to memory stops, including the extra 2 kB allocated to
alleviate the conflict of storing the newest data while reading the oldest when
the area is not fill-and-stop, or is ringing around. Therefore, if the CPU does
466
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