Allen-Bradley Logix5000 - Page 392

392 Rockwell Automation Publication 1756-RM003N-EN-P - October 2011
Chapter 8 Array (File)/Misc. Instructions (FAL, FSC, COP, CPS, FLL, AVE, SRT, STD, SIZE)
Description: The standard deviation is calculated according to this formula:
Where:
· start = dimension-to-vary subscript of the array operand
· x
i
= variable element in the array
· N = number of specified elements in the array
· AVE =
IMPORTANT
Make sure the length does not cause the instruction to
exceed the specified dimension to vary. If this happens, the
destination will be incorrect.
X
start i+()
AVE–
2
[]
i 1=
N





N 1–()
--------------------------------------------------------------------
Standard Deviation =
x
start i+()
i 1=
N





N
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