CR300-Series Datalogger
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• 3.3 V control — Configured for control, SE terminals 1-4 supply 3.3
V. Voltage will drop to 3.0 V when sourcing 100 µA.
• 5 V control — Control terminals C1 and C2 supply 5 V. Voltage will
drop to 3.5 V when sourcing 10 mA.
• Switched 12 V — The SW12V terminal provides unregulated 12 V
and will source 500 mA. The voltage on this terminal fluctuates with
the dc supply used to power the CR300.
• Continuous 12V — Bat + and – provide a connection to the
unregulated, nominal 12 V battery. It may rise above or drop below
the power requirement of the sensor or peripheral. Take precautions to
prevent damage to sensors or peripherals from over- or undervoltage
conditions, and to minimize the error associated with the measurement
of underpowered sensors.
6.8 Memory
Final storage memory for the CR300 is organized in 4 KB sectors of serial
flash. Each sector is rated for 100,000 serial flash erases. TABLE 6-5 provides
a description of each memory location and the types of data each stores.
TABLE 6-5. CR300 Memory Allocation
Memory Size Type Storage
CPU Drive 5 MB Serial Flash
Datalogger Programs
Other Files
Data Storage 10 MB Serial Flash
Data
DNP3 Events
Operating System 2 MB Flash Operating System
RAM 756 KB RAM
Background Tasks, Buffers,
System Memory, Program
Memory, Table Memory,
Program Variables
Data concerning CR300 memory are posted in the Status and DataTableInfo
tables.
6.8.1 Data Storage
During data table initialization, sectors are assigned to each data table
according to the parameters set in the program. Program options that affect the
allocation of memory include the Size parameter of the DataTable()
instruction, the Interval and Units parameters of the DataInterval()
instruction, and the Interval and Units parameters of the Scan() instruction.
The CR300 uses those parameters to assign sectors in a way that maximizes the
life of its memory.
When a data table is set up, an initial memory sector is erased to prepare for
new data. Erasing a sector can take up to 100 ms. Each data table undergoes
this initialization process. As data are written to memory and a sector fills, the
next assigned sector is erased in preparation for new data to be written to it.
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