Less Than (LT)

When enabled, the LT instruction and the operator tests Source A is less than Source B.
Available Languages
Ladder Diagram
LT ladder instruction
Operands
There are data conversion rules for mixing numeric data types within an instruction. See Data conversions.
Ladder Diagram
Numeric Comparison
Operand
Data Type
Format
Description
Source A
SINT
INT
DINT
LINT
USINT
UINT
UDINT
ULINT
REAL
LREAL
immediate
tag
Value to test against Source B
Source B
SINT
INT
DINT
LINT
USINT
UINT
UDINT
ULINT
REAL
LREAL
immediate
tag
Value to test against Source A
Affects Math Status Flags
No
Major/Minor Faults
See Index through arrays for array-indexing faults.
Execution
Ladder Diagram
Condition/State
Action Taken
Prescan
N/A
Rung-condition-in is false
Set Rung-condition-out to Rung-condition-in
Rung-condition-in is true
Numeric compare:
If Source A and Source B are not NANs and Source A is less than Source B.
Set Rung-condition-out to true
else
Clear Rung-condition-out to false.
Postscan
N/A
Example
Ladder Diagram
LT ladder example
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