Campbell Scientific CR9000X Measurement and Control System - Manual (Page 291)

Section 8. Processing and Math Instructions
Both have the same effect, X will be set to –1 if Temp(1) is greater than 50 and
Temp(3) is less than 20. X will be set to 0 if either expression is false.
ASIN (Source)
The ASIN function returns the arc sin of a number.
Syntax
x = ASIN (source)
Remarks
Source can be any valid numeric expression that has a value between -1 and 1
inclusive.
The ASIN function takes the ratio of two sides of a right triangle and returns the
corresponding angle. The ratio is the length of the side opposite to the angle
divided by the length of the hypotenuse. The result is expressed in radians and
is in the range -
π
/2 to
π
/2 radians. If it is desired to use degrees instead of
radians for the inputs and results of the trig functions in a program, the
"AngleDegrees" declaration instruction can be used.
To convert degrees to radians, multiply degrees by π /180. To convert radians to
degrees, multiply radians by 180/ π .
ASIN is the inverse trigonometric function of Sin, which takes an angle as its
argument and returns the length ratio of the side opposite the angle to the
hypotenuse.
ASIN Function Example
The example uses ASIN to calculate
π. By definition, a full circle is 2 π
radians.
ASIN(1) is
π
/2 radians (90 degrees).
Public Pi 'Declare variables.
Pi = 2 * ASIN ( 1 ) 'Calculate Pi.
ATN(Source)
Returns the arctangent of a number.
Syntax
Atn( source )
Remarks
The argument source can be any valid numeric expression.
The ATN function takes the ratio (source) of two sides of a right triangle and returns
the corresponding angle. The ratio is the length of the side opposite the angle
divided by the length of the side adjacent to the angle. The result is expressed in
radians and is in the range -
π
/2 to
π
/2 radians.
π
is approximately 3.141593.
If it is desired to use degrees instead of radians for the inputs and results of the
trig functions in a program, the "AngleDegrees" declaration instruction can be
used.
8-5