Campbell CR6 Series, Руководство оператора

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Section 7. Installation
255
can use the BOOL8 data type. A BOOL8 is a one-byte value that holds eight bits
of information (eight states with one bit per state). To store the same information
using a 32 bit BOOLEAN data type, 256 bits are required (8 states * 32 bits per
state).
When programming with BOOL8 data type, repetitions in the output processing
DataTable()
instruction must be divisible by two, since an odd number of bytes
cannot be stored. Also note that when the CR6 converts a LONG or FLOAT data
type to BOOL8, only the least significant eight bits of the binary equivalent are
used, i.e., only the binary representation of the decimal integer modulo divide
(p.
591)
256 is used.
Example:
Given: LONG integer 5435
Find: BOOL8 representation of 5435
Solution:
5435 / 256 = 21.2304687
0.2304687 * 256 = 59
Binary representation of 59 = 00111011 (CR6 stores these bits
in reverse order)
When datalogger support software
(p. 97)
retrieves the BOOL8 value, it splits it
apart into eight fields of -1 or 0 when storing to an ASCII file. Consequently,
more memory is required for the ASCII file, but CR6 memory is conserved. The
compact BOOL8 data type also uses less comms band width when transmitted.
CRBasic example Bool8 and Bit Shift Operators
(p. 257)
programs the CR6 to
monitor the state of 32 "alarms" as a tutorial exercise. The alarms are toggled by
manually entering zero or non-zero (e.g., 0 or 1) in each public variable
representing an alarm as shown in figure Alarms Toggled in Bit Shift Example
(p.
256).
Samples of the four public variables FlagsBool8(1) , FlagsBool8(2) ,
FlagsBool8(3)
, and
FlagsBool8(4)
are stored in data table Bool8Data as four
one-byte values. However, as shown in figure Bool8 Data from Bit Shift
Example (Numeric Monitor)
(p. 256),
when viewing the data table in a numeric
monitor
(p. 592),
data are conveniently translated into 32 values of True or False .
In addition, as shown in figure
Bool8 Data from Bit Shift Example (PC Data File)
(p. 257),
when datalogger support software
(p. 97)
stores the data in an ASCII file, it is
stored as 32 columns of either -1 or 0 , each column representing the state of an
alarm. You can use variable aliasing
(p. 199)
in the CRBasic program to make the
data more understandable.