L9E_ARCOS: Floating Point Arc Cosine of an Angle (in Radians)
(Original Document)
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Naming
Name in LL984 Editor
Function Block Name
name of legacy 984 instruction
name in other tools and editors like:
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Function Description
The L9E_ARCOS DFB performs the arc-cosine function on a floating point value and stores the result in an array.
Representation
Parameters
Input Pin
Name
Data Type
Address Range
Meaning
Top
ENABLE
BOOL
–
ON = calculates arc cosine of the value
Node
Node Type
Name
Data Type
Address Range
Meaning
Top
IN
COSVAL
ARRAY[1...2]OF UINT
%MW
floating point value indicating the cosine of an angle
COSVAL stores a floating point value indicating the cosine of an angle between 0 through Pi radians.
This value must be in the range of -1.0 through +1.0; if not:
  • The arc cosine is not computed.
  • An invalid result is returned.
  • An event is flagged in the L9E_ERLOG DFB.
Middle
IN/OUT
RESULT
ARRAY[1...4] OF UINT
%MW
Arc cosine in radians of the value in COSVAL
The arc cosine in radians of the floating point value is posted in word 3 and 4.
Word 1 and 2 are not used but allocation is required.
Note: To preserve space, you can make the %MW reference numbers assigned to word 1 and 2 equal to COSVAL, since word 1 and 2 are not used.
Output Pin
Name
Data Type
Address Range
Meaning
Top
OUT
BOOL
–
ON = operation successful