Variables - Campbell CR300 Series Product Manual

Table 12-1: Data types, ranges and resolutions
Data type Description
IEEE four-byte
Float
floating point
Long
signed integer
Boolean
signed integer
String ASCII String
Campbell Scientific
FP2
two-byte floating point
NSEC eight-byte time stamp

12.4.1 Variables

In CRBasic, the declaration of variables (via the
optional type descriptor
Boolean, and String. The default type is Float.
Example variables declared with optional data types
Public As Float
PTemp
Public As Long
Counter
Public As String
SiteName
As Float
specifies the default data type. If no data type is explicitly specified with the
Float
statement, then
performed internally in IEEE 4 byte floating point with some operations calculated in double
precision. A good rule of thumb is that resolution will be better than 1 in the seventh digit.
As Long
specifies the variable as a 32 bit integer. There are two possible reasons a user would
do this: (1) speed, since the CR300 series Operating System can do math on integers faster than
with Floats, and (2) resolution, since the
Float. A good application of the
large.
As Boolean
specifies the variable as a 4 byte Boolean. Boolean variables are typically used for
flags and to represent conditions or hardware that have only 2 states (e.g., On/Off, High/Low). A
Boolean variable uses the same 32 bit long integer format as a
two values: True, which is represented as –1, and false, which is represented with 0. When a
+/–1.8 *10^–38 to
four-byte –2,147,483,648 to
four-byte
As that specifies the data type. The data types are Float, Long,
, Batt_volt
* 24
is assumed. Measurement variables are stored and calculations are
As Long
Range
+/–3.4 *10^38 (about 7 digits)
+2,147,483,647
–1, 0
–7999 to +7999
(about 4 digits)
DIM PUBLIC
or the
Long
has 31 bits compared to the 24 bits in the
declaration is a counter that is expected to get very
Resolution Where used
24 bits
1 bit variables, output
True (–1) or variables,
False ( 0) sample output
variables,
sample output
13 bits
nanoseconds variables, output
statement) allows an
Long
but can set to only one of
12. Working with data
variables
output
As
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