Less Than or Equal To (LEQ)
The LEQ instruction tests whether Source A is less than or equal to Source B.
Available Languages
- Ladder Diagram
- Function Block
- Structured Text
This instruction is not available in structured text. *
* There is no equivalent structured text instruction. Use other structured text programming to achieve the same result.
Operands
- Ladder Diagram
- Function Block
- Structured Text
Use adjacent less than and equal signs "<=" as an operator within an expression. This expression evaluates whether sourceA is less than or equal to sourceB.
IF sourceA <= sourceB THEN
<statements>;
FBD_COMPARE Structure
Example
If value_1 is less than or equal to value_2, set light_2. If value_1 is greater than value_2, clear light_2.
- Ladder Diagram
- Function Block
- Structured Text
light_2 := (value_1 <= value_2);
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Available Languages
- Ladder Diagram
- Function Block
- Structured Text
This instruction is not available in structured text. *
* There is no equivalent structured text instruction. Use other structured text programming to achieve the same result.
Operands
- Ladder Diagram
Operand | Type | Format | Description | Notes |
Source A | SINT INT DINT REAL String type | Immediate tag | value to test against Source B | If you enter a SINT or INT tag, the value converts to a DINT value by sign-extension. String types are: - default STRING data type - any new string type you create To test the characters of a string, enter a string type for both Source A and Source B. |
Source B | SINT INT DINT REAL String type | Immediate tag | value to test against Source A |
- Function Block
Operand | Type | Format | Description |
LEQ tag | FBD_COMPARE | structure | LEQ structure |
- Structured Text
Use adjacent less than and equal signs "<=" as an operator within an expression. This expression evaluates whether sourceA is less than or equal to sourceB.
IF sourceA <= sourceB THEN
<statements>;
FBD_COMPARE Structure
Input Parameter | Data Type | Description |
EnableIn | BOOL | Enable input. If cleared, the instruction does not execute and outputs are not updated. Default is set. |
SourceA | REAL | Value to test against SourceB Valid = any float |
SourceB | REAL | Value to test against SourceA Valid = any float |
Output Parameter | Data Type | Description |
EnableOut | BOOL | Enable output. |
Dest | BOOL | Result of the instruction. This is equivalent to rung-condition-out of the ladder diagram LEQ instruction. |
Example
If value_1 is less than or equal to value_2, set light_2. If value_1 is greater than value_2, clear light_2.
- Ladder Diagram
- Function Block
- Structured Text
light_2 := (value_1 <= value_2);
- Download to PDF
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