Allen-Bradley LOGIX 5000 Reference Manual page 359

Select_Limit Instructions
HL_LIMIT Structure
Input Parameter Data Type
EnableIn BOOL
In REAL
HighLimit REAL
LowLimit REAL
SelectLimit DINT
Output Parameter Data Type
EnableOut BOOL
Out REAL
HighAlarm BOOL
LowAlarm BOOL
Status DINT
InstructFault (Status.0) BOOL
LimitsInv (Status.1) BOOL
SelectLimitInv (Status.2) BOOL
Rockwell Automation Publication 1756-RM006K-EN-P - November 2018
Description
Enable input. If false, the instruction does not execute and outputs
are not updated.
Default is true.
The analog signal input to the instruction.
Valid = any float
Default = 0.0
The high limit for the Input. If SelectLimit = 0 and HighLimit
LowLimit, the instruction sets the appropriate bit in Status and sets
Out = LowLimit.
Valid = HighLimit > LowLimit
Default = 0.0
The low limit for the Input. If SelectLimit = 0 and LowLimit
HighLimit, the instruction sets the appropriate bit in Status and
sets Out = LowLimit.
Valid = LowLimit < HighLimit
Default = 0.0
Select limit input. This input has three settings:
0 = Use both limits
1= Use high limit
2 = Use low limit
If SelectLimit is invalid, the instruction assumes SelectLimit = 0
and sets the appropriate bit in Status.
Valid = 0 to 2
Default = 0
Description
Indicates if instruction is enabled. Cleared to false if Out overflows.
The calculated output of the algorithm.
The high alarm indicator. Set to true when In
HighAlarm is disabled when SelectLimit is set to 2.
The low alarm indicator. Set to true when In
LowAlarm is disabled when SelectLimit is set to 1.
Status of the function block.
The instruction detected one of the following execution errors. This
is not a minor or major controller error. Check the remaining status
bits to determine what occurred.
HighLimit LowLimit.
The value of SelectLimit is not a 0, 1, or 2.
Chapter 4
HighLimit. The
LowLimit. The
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