Specifications

Section 2. Data Storage and Retrieval
The CR3000 can store individual measurements or it may use its extensive processing
capabilities to calculate averages, maxima, minima, histograms, FFTs, etc., on periodic or
conditional intervals. Data are stored in tables. The number of tables and the values to
output in each table are selected when running Short Cut (Overview) or when writing a
datalogger program directly (Sections 4 – 9).
2.1 Data Storage in CR3000
There are two possible areas for data storage on the CR3000:
1) Internal SRAM
2) The optional CFM100 Compact Flash Module and NL115 Ethernet
Interface and Compact Flash Module allow storing data in a compact
flash card.
Internal SRAM is used as either the sole storage area for a data table or as a
buffer area when data are sent to compact flash (CF) card.
When the CR3000 gets a request for data that is stored on a CF card, the
CR3000 only looks for the data in the CF card when the oldest data are
requested or if the data are not available in internal RAM.
In the CRBASIC program, the DataTable instruction sets the size of the data
table or buffer area. A data table can be stored in a CF card by including the
CardOut instruction within the data table declaration.
2.1.1 Internal SRAM
Internal SRAM is used as either the sole storage area for a data table or as a
buffer area when data are sent to a CF card. The maximum number of data
tables that can be created is 30. Internal SRAM is battery backed. Data
remain in memory when the CR3000 is powered down. Data in SRAM are
erased when a different program is loaded and run.
There are 4 Mbyte of SRAM. Some of this is used by the operating system
and for CPU usage and program storage. The rest is available for data storage.
When a new program is compiled, the CR3000 checks that there is adequate
space in SRAM for the data tables; a program that requests more space than is
available will not run.
2.1.2 CFM100 or NL115
The CFM100 and NL115 are optional modules that plug onto the CR3000
peripheral port and have a slot for a Type I or Type II CF card. CF cards
expand the CR3000’s storage capacity. A program can send a maximum of 30
data tables to a CF card.
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