Campbell CR6 Series, Operator'S Manual

Page: 188 / 690

Section 7. Installation
188
Data Types in Variable Memory
Name Command Description
Word
Size
(Bytes)
Notes Resolution / Range
Long As Long Signed integer 4
Use to store count data in the
range of
±
2,147,483,648
Speed: integer math is faster
than floating point math.
Resolution: 32 bits. Compare
to 24 bits in IEEE4.
Suitable for storing whole
numbers, counting number,
and integers in final-storage
memory. If storing
non-integers, the fractional
portion of the value is lost.
32 bits
–2,147,483,648 to +2,147,483,647
Boolean
As
Boolean
Signed integer 4
Use to store true or false
states, such as states of flags
and control ports. 0 is always
false. –1 is always true.
Depending on the application,
any other number may be
interpreted as true or false.
See the section True = -1,
False = 0
(p. 224).
True = – 1 or any number ≥ 1
False = any number ≥ 0 and < 1
String
As String
ASCII string
Minimum
: 3 (4
with null
terminato
r)
Default:
24
Maximu
m:
limited
only to
the size of
available
CR6
memory.
See caution.
1
String size is defined by the
CR6 operating system and
CRBasic program.
When converting from
STRING to FLOAT ,
numerics at the beginning of a
string convert, but conversion
stops when a non-numeric is
encountered. If the string
begins with a non-numeric,
the
FLOAT
will be
NAN
. If
the string contains multiple
numeric values separated by
non-numeric characters, the
SplitStr() instruction can be
used to parse out the numeric
values. See the sections String
Operations
(p. 379)
and
Serial
I/O
(p. 356).
Unless declared otherwise, string size is 24
bytes or characters. String size is allocated
in multiples of four bytes; for example,
String * 25 , String * 26 , String * 27 , and
String * 28 allocate 28 bytes (27 usable).
Minimum string size is 4 (3 usable). See
CRBasic Editor Help for more information.
Maximum length is limited only by
available CR6 memory. As a special case,
a string can be declared as String * 1 . This
allows the efficient storage of a single
character. The string will take up 4 bytes in
memory and when stored in a data table,
but it will hold only one character.
1
CAUTION When using a very long string in a variable declared Public , the operations of datalogger support software
(p. 663)
will
frequently transmit the entire string over the communication link. If communication bandwidth is limited, or if communications are
paid for by they byte, declaring the variable Dim may be preferred.