Allen-Bradley LOGIX 5000

Statistical Instructions
Chapter 5
Rockwell Automation Publication 1756-RM006K-EN-P - November 2018 399
Execution
Function Block
Condition/State Action Taken
Prescan EnableIn and EnableOut bits are cleared to false.
Tag.EnableIn is false EnableIn and EnableOut bits are cleared to false.
Tag.EnableIn is true EnableIn and EnableOut bits are set to true.
The instruction executes.
Instruction first run Initialize the previous Output and Average.
Instruction first scan Initialize Out to zero.
Initialize Average to Input
Initialize the instruction algorithm.
Postscan EnableIn and EnableOut bits are cleared to false.
Structured Text
Condition/State Action Taken
Prescan See Prescan in the Function Block table.
Normal Execution See Tag.EnableIn is true in the Function Block table.
Postscan See Postscan in the Function Block table.
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