Allen-Bradley LOGIX 5000 Reference Manual page 399

Statistical Instructions
Execution
Function Block
Condition/State
Prescan
Tag.EnableIn is false
Tag.EnableIn is true
Instruction first run
Instruction first scan
Postscan
Structured Text
Condition/State
Prescan
Normal Execution
Postscan
Example
Each scan that SampleEnable is set, the instruction places the value of In into array
storage, calculates the standard deviation of the values in array storage, and places
the result in Out. Out becomes an input parameter for function_block_C.
Function Block
Rockwell Automation Publication 1756-RM006K-EN-P - November 2018
Action Taken
EnableIn and EnableOut bits are cleared to false.
EnableIn and EnableOut bits are cleared to false.
EnableIn and EnableOut bits are set to true.
The instruction executes.
Initialize the previous Output and Average.
Initialize Out to zero.
Initialize Average to Input
Initialize the instruction algorithm.
EnableIn and EnableOut bits are cleared to false.
Action Taken
See Prescan in the Function Block table.
See Tag.EnableIn is true in the Function Block table.
See Postscan in the Function Block table.
Chapter 5
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