Allen-Bradley LOGIX 5000 Reference Manual page 360

Chapter 4 Select_Limit Instructions
360
Structured Text
Operand Type
HLL tag HL_LIMIT
See Structured Text Syntax for more information on the syntax of expressions
within structured text.
Description
The HLL instruction determines the value of the Out using these rules:
Selection
SelectLimit = 0
(use high and low limits)
SelectLimit = 1
(use high limit only)
SelectLimit = 2
(use low limit only)
Affects Math Status Flags
No
Major/Minor Faults
None specific to this instruction. See Common Attributes for operand-related
faults.
Execution
Function Block
Condition/State
Prescan
Tag.EnableIn is false
Tag.EnableIn is true
Instruction first run
Instruction first scan
Postscan
Rockwell Automation Publication 1756-RM006K-EN-P - November 2018
Format Description
structure HLL structure
Condition Action
In < HighLimit and Out = In
In > LowLimit
In HighLimit Out = HighLimit
In LowLimit Out = LowLimit
HighLimit LowLimit Out = LowLimit
In < HighLimit Out = In
In HighLimit Out = HighLimit
In > LowLimit Out = In
In LowLimit Out = LowLimit
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.
N/A
N/A
EnableIn and EnableOut bits are cleared to false.