Rockwell Automation GMLC Reference Manual - Manual (Page 679)

Publication GMLC-5.2 - November 1999
642 Mathematical Functions
The argument can be any floating point value or expression, but it must
have a value from -1 to 1, inclusive, because the sine of an angle is always
within this range. The value of the Arc_sine function is always an angle
from -
π
/
2
to
π
/
2
radians (±90°), inclusive. If the argument is not between
±1, the value of the Arc_sine function is zero.
For example, the following expression is evaluated as 0.5235xx since the
principal angle whose sine is 0.5 is 0.5235 radians (30°).
Arc_sine (0.5)
To convert the value of the Arc_sine function to degrees, multiply by 180 /
π
.
For example, the following expression is evaluated as 30 (assuming the
user constant
Pi has been defined as the value of
π
) since the principal
angle whose sine is 0.5 is 30°.
(Arc_sine(0.5) * 180 / Pi)
Arc Tangent
The value of the Arc_tangent function is the principal angle (in radians)
whose tangent is equal to the argument, as shown below.
Argument –1
+
–
+1
−π
/2
π
/2