User manual

PMAC User Manual
156 Computational Features
ASIN
Function
inverse sine (arc-sine) function with its range reduced to
+/-90 degrees.
Syntax
ASIN ({expression})
Domain
-1.0 — 1.0
Domain units
none
Range
-Pi/2 — Pi/2 radians (-90 — 90 degrees)
Range units
radians/degrees
Possible errors
Illegal Domain
ACOS
Function
inverse cosine (arc-cosine) function with its range reduced
to 0 — 180 degrees.
Syntax
ACOS ({expression})
Domain
-1.0 — 1.0
Domain units
none
Range
0 — Pi radians (0 — 180 degrees)
Range units
radians/degrees
Possible errors
Illegal Domain
ATAN
Function
standard inverse tangent (arc-tangent) function.
Syntax
ATAN ({expression})
Domain
all reals
Domain units
none
Range
-Pi/2 — Pi/2 radians (-90 — 90 degrees)
Range units
radians/degrees
Possible errors
none
ATAN2
This function returns the angle whose sine is the expression in parentheses and whose cosine is the value
of Q0 for that coordinate system. (Actually, it is only the ratio of the magnitudes of the two values, and
their signs, that matter in this function). It is distinguished from the standard ATAN function by the use of
two arguments. The advantage of this function is it has a full 360 degree range, rather than the 180
degree range of the single-argument ATAN function.
Function
expanded arctangent function
Syntax
ATAN2 ({expression})
Domain
all reals
Domain units
none
Range
-Pi — Pi radians (-180 — 180 degrees)
Range units
radians/degrees
Possible errors
none
Note:
If doing the calculation in a PLC program, make sure that the proper coordinate
system has been addressed in that PLC program.