Campbell-scientific CR1000 Measurement and Control System Manual de usuario descargar pdf (Pagina 339)

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101

Section 8. Operation

339

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

CR1000reportsbacktothedataloggersupportsoftware31bits,ora

maximumof&h7fffffff,thenitrestartsat0.Iftherecordnumber

incrementsonceasecond,restartatzerowilloccuraboutonceevery

68years.

8.3.2 Memory Conservation

One or more of the following memory-saving techniques can be used on the rare

occasions when a program reaches memory limits:

• Declare variables as DIM instead of Public. DIM variables do not require

buffer memory for data retrieval.

• Reduce arrays to the minimum size needed. Arrays save memory over the

use of scalars as there is less "meta-data" required per value. However, as a

rough approximation, 192000 (4-kB memory) or 87000 (2-kB memory)

variables will fill available memory.

• Use variable arrays with aliases instead of individual variables with unique

names. Aliases consume less memory than unique variable names.

• Confine string concatenation to DIM variables.

• Dimension string variables only to the size required.

Read More! More information on string variable-memory use and conservation is

available in String Operations (p. 236).

8.3.3 Memory Reset

Four features are available for complete or selective reset of CR1000 memory.

8.3.3.1 Full Memory Reset

Full memory reset occurs when an operating system is sent to the CR1000 using

DevConfig or when entering 98765 in the Status table field FullMemReset. A

full memory reset does the following:

• Clears and formats CPU: drive (all program files erased).

• Clears SRAM data tables.

• Clears Status-table elements

• Restores settings to default.

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