Inverse Trig - Asin, Acos, And Atan - GE PACSystems RX7i Cpu Programmer's Reference Manual

Chapter 4. Ladder Diagram (LD) Programming
4.1.4 Inverse Trig – ASIN, ACOS, and ATAN
When an Inverse Sine (ASIN), Inverse Cosine (ACOS), or Inverse Tangent (ATAN) function receives
power flow, it respectively computes the inverse sine, inverse cosine or inverse tangent of IN and
stores the result in radians in output Q.
The ASIN and ACOS functions accept a narrow range of input values, where –1 ≤ IN ≤ 1. Given a valid
value for the IN parameter, the ASIN function produces a result Q such that:
π π
   
ASIN(IN) Q
2 2
The ACOS function produces a result Q such that:
   
π
ACOS(IN) 0 Q
The ATAN function accepts the broadest range of input values, where –
value for the IN parameter, the ATAN function produces a result Q such that:
π
   
ATAN(IN) Q
2
The power flow output is energized unless one of the following invalid conditions occurs:
IN is outside the valid range for ASIN, ACOS, or ATAN
■
IN is a NaN (Not a Number)
■
Operands of Inverse Trig Functions
Parameter Description
IN The REAL or LREAL value to process.
ASIN and ACOS: -1  IN  1
ATAN: –∞ ≤ IN ≤ +∞
Q Trigonometric value of IN. REAL or
LREAL value expressed in radians.
ASIN: (-/2)  Q  (/2)
ACOS: 0  Q  
ATAN: (-/2)  Q  (/2)
66 PACSystems* RX7i, RX3i and RSTi-EP CPU Programmer's Reference Manual
Mnemonics:
ASIN_REAL
ASIN_LREAL
ACOS_REAL
ACOS_LREAL
ATAN_REAL
ATAN_LREAL
π
2
Allowed Operands
All except variables located in %S - %SC
All except constants and variables located in
%S - %SC
∞ ∞
≤ IN ≤ + . Given a valid
Optional
No
No
GFK-2950C