Campbell-scientific CR3000 Micrologger Uživatelský manuál stáhnout pdf (Strana 149)

100

101

Section 7. Installation

149

BeginProg

Fa = 0

Fb = 0.125

L = 126

Ba = Fa 'This will set Ba = False (0)

Bb = Fb 'This will Set Bb = True (-1)

Bc = L 'This will Set Bc = True (-1)

EndProg



FLOAT from LONG or Boolean

When a LONG or Boolean is converted to FLOAT, the integer value is loaded

into the FLOAT. Booleans are converted to -1 or 0. LONG integers greater than

24 bits (16,777,215; the size of the mantissa for a FLOAT) will lose resolution

when converted to FLOAT.

LONG from FLOAT or Boolean

When converted to Long, Boolean is converted to -1 or 0. When a FLOAT is

converted to a LONG, it is truncated. This conversion is the same as the INT

function (Arithmetic Functions

(p. 500) ). The conversion is to an integer equal to or

less than the value of the float (e.g., 4.6 becomes 4, -4.6 becomes -5).

If a FLOAT is greater than the largest allowable LONG (+2,147,483,647), the

integer is set to the maximum. If a FLOAT is less than the smallest allowable

LONG (-2,147,483,648), the integer is set to the minimum.

Integers in Expressions

LONGs are evaluated in expressions as integers when possible. CRBasic example

Evaluation of Integers

(p. 149) illustrates evaluation of integers as LONGs and

FLOATs.

CRBasicExample21. EvaluationofIntegers

Public X, I As Long

BeginProg

I = 126

X = (I+3) * 3.4

'I+3 is evaluated as an integer, then converted to FLOAT before

'it is multiplied by 3.4

EndProg



Constants Conversion

Constants are not declared with a data type, so the CR3000 assigns the data type

as needed. If a constant (either entered as a number or declared with CONST) can

be expressed correctly as an integer, the compiler will use the type that is most

efficient in each expression. The integer version is used if possible, i.e., if the

expression has not yet encountered a FLOAT. CRBasic example Constants to

LONGs or FLOATs

(p. 150) lists a programming case wherein a value normally

considered an integer (10) is assigned by the CR3000 to be As FLOAT.

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