Campbell Scientific LoggerNet Datalogger Support Software - Manual (Page 520)

Appendix C. Table-Based Dataloggers
Event driven tables should have a fixed size rather than allowing
them to be allocated automatically. Event driven tables in
CR10X-TD type dataloggers that are automatically allocated are
assumed to have one record stored per execution interval in
calculating the length. Since the datalogger tries to make the
tables fill up at the same time, with programs using short execution
intervals these event driven tables may take up most of the
memory leaving very little for the other, longer interval,
automatically allocated data tables.
C.1.2 CR5000/CR1000/CR3000/CR800/CR9000 Memory for
Programs and Data Storage
The datalogger memory for the CR5000, CR1000, CR3000, CR800, and
CR9000 is divided between Random Access Memory (RAM) and Electrically
Erasable Programmable Read Only Memory (EEPROM). The EEPROM, or
flash memory, is used to store the operating system and the user programs that
have been saved in the datalogger. When the datalogger powers up, the
program marked as “Run on Power-up” is transferred to RAM and executes
from there. For some dataloggers, additional storage is available using
PCMCIA or Compact Flash cards.
Final storage tables are made up of records and fields. Each row in a table
represents a record and each column represents a field. The number of fields in
a record is determined by the number and configuration of output processing
instructions that are included as part of the Data Table definition.
The number of records to be kept in a table before the oldest data is overwritten
can be limited by the user, or left for the datalogger to determine automatically.
The datalogger tries to set the sizes of automatically allocated tables such that
all of the tables will fill up at about the same time. Once the sizes of the tables
are determined, the datalogger allocates the available memory to these tables.
If the amount of memory requested for the data tables exceeds the available
memory, the program will not run.
Event driven tables should have a fixed size rather than allowing
them to be allocated automatically. If automatically allocated,
event driven tables are assumed to have one record stored per
execution interval in calculating the length. Since the datalogger
tries to make the tables fill up at the same time, with programs
using short execution intervals these event driven tables may take
up most of the memory leaving very little for other, longer
interval, automatically allocated data tables.
C.1.3 CR200 Series Dataloggers
CR200 Series dataloggers are similar to the other CRX000 dataloggers
regarding the format of final storage. Data is stored in final storage tables that
are made up of records and fields. As with the other table-based dataloggers,
the user can specify the number of records for each table, or table-size can be
determined by the datalogger. And as with the other dataloggers, the size of
event driven tables should always be entered by the user, or else the datalogger
NOTE
NOTE
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