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11-22 Chapter 11
GSE Scale Systems
Therefore, when a recall is performed on a database which includes the
time/date parameter 11) as a column, the recalled time/date is ignored. If
the time is required to be recalled it is recommended that it is first copied
into a variable and then create the row. The variable could be a U-INT
type if the recalled time is to be left in its original raw form. If a string type
variable is used the data could be formatted and copied to the string in a
form such as 09\12\96 before the row is created. Once this parameter is
recalled it can then be printed using the Custom Transmits or accessed to
view the recalled time/date.
The time/date is handled in a special manner which is somewhat common
in computers. It is stored as the number of seconds elapsed since
midnight on January 1, 1970. Currently this value is around 800,000,000.
At the rate of 86400 seconds per day (60 x 60 x 24), (31,536,000 per year)
this value changes quickly.
Keeping track of time and date in this manner simplifies the process of
calculating the difference between two times. It also compacts the
information such that it can be stored in 4 bytes of memory, helping to
keep the number of memory bytes required to store a row as small as
possible.
D
I
ATABASE
NFORMATION
The database information parameters begin at P60010 à P60053. The
information parameters supply information about the amount of memory
installed, available, already used for by the database option, number of
rows used, etc. These parameters are described in detail in Chapter 14,
Information Parameters beginning on page 14-2.
D
EFAULTING THE
P65010 can be used to completely clear out the controller database data
and setup. However, the deletion is not final until you exit the setup mode
and save all changes.
Use the following procedure to clear out the database.
•
Press [ENTER] to simply default the database setups. Whether or not
any database memory is allocated to general usage is not affected.
Allocating database memory to general usage can be used to allow
variably sized setup modes (such as Custom Transmit setup and macro
setup) to increase when they would otherwise be limited by the occurrence
of the "Out Of RAM" error message. If this is done, the only limitation on
the amount of information entered into these setup modes is the amount of
available EEPROM memory.
M
C
EMORY
ONSUMPTION
When a database RAM option is completely blank, P60020 will indicate
that 14 bytes are in use. This amount is due to the initialization of the
module to make it usable for database operations.
You can approximate the amount of memory required for your particular
database application. Simply access P60033 before and after you define a
database to determine the number of bytes that the database definition
P
ARAMETERS
E
D
NTIRE
ATABASE
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