The MEQ instruction passes the Source and Compare values through a Mask and compares the results.

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
Source	SINT INT DINT	immediate tag	value to test against Compare
Mask	SINT INT DINT	immediate tag	which bits to block or pass
Compare	SINT INT DINT	immediate tag	value to test against Source

-    Function Block

Operand	Type	Format	Description
MEQ tag	FBD_MASK_EQUAL	structure	MEQ structure

-    Structured Text
Structured text does not have an MEQ instruction, but you can achieve the same results using structured text.

IF (Source AND Mask) = (Compare AND Mask) THEN
<statement>;
END_IF;

FBD_MASK_EQUAL 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.
Source	DINT	Value to test against Compare. Valid = any integer
Mask	DINT	Defines which bits to block (i.e., mask). Valid = any integer
Compare	DINT	Compare value. Valid = any integer

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 MEQ instruction.

Examples
Example 1
If the masked value_1 is equal to the masked value_2, set light_1. If the masked value_1 is not equal to the masked value_2, clear light_1.

This example shows that the masked values are equal. A 0 in the mask restrains the instruction from comparing that bit (indicated by an x in the example).

-    Ladder Diagram

-    Function Block

-    Structured Text
light_1 := ((value_1 AND mask_1)=(value_2 AND mask_2));


Example 2
If the masked value_1 is equal to the masked value_2, set light_1. If the masked value_1 is not equal to the masked value_2, clear light_1.

This example shows that the masked values are not equal. A 0 in the mask restrains the instruction from comparing that bit (indicated by an x in the example).

-    Ladder Diagram

-    Function Block

-    Structured Text
light_1 := ((value_1 AND mask_1)=(value_2 AND mask_2));


- Download to PDF

Read More »

The LIM instruction tests whether the Test value is within the range of Low Limit to the High Limit.

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
Low limit	SINT INT DINT REAL	immediate tag	value of lower limit
Test	SINT INT DINT REAL	immediate tag	value to test
High limit	SINT INT DINT REAL	immediate tag	value of upper limit

-    Function Block

Operand	Type	Format	Description
LIM tag	FBD_LIMIT	structure	LIM structure

-    Structured Text
Structured text does not have a LIM instruction, but you can achieve the same results using structured text.

IF LowLimit <= HighLimit AND
 (Test >= LowLimit AND Test <= HighLimit)) OR
 (LowLimit >= HighLimit AND
 (Test <= LowLimit OR Test >= HighLimit)) THEN
<statements>;
END_IF;

FBD_LIMIT 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.
LowLimit	REAL	Value of lower limit. Valid = any float
Test	REAL	Value to test against limits. Valid = any float
HighLimit	REAL	Value of upper limit. 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 LIM instruction.

Examples
Example 1: Low Limit <= High Limit
When 0 <= value >= 100, set light_1. If value < 0 or value > 100, clear light_1.

-    Ladder Diagram

-    Function Block

-    Structured Text
IF (value <= 100 AND (value >= 0 AND value <= 100)) OR
 (value >= 100 AND value <= 0 OR value >= 100)) THEN
  light_1 := 1;
ELSE
  light_1 := 0;
END_IF;


Example 2: Low Limit >= High Limit
When value >= 0 or value <= -100, set light_1. If value < 0 or value > -100, clear light_1.

-    Ladder Diagram

-    Function Block

-    Structured Text
IF (0 <= -100 AND value >= 0 AND value <= -100)) OR
 (0 >= -100 AND (value <= 0 OR value >= -100)) THEN
  light_1 := 1;
ELSE
  light_1 := 0;
END_IF;


- Download to PDF

Read More »

The LES instruction tests whether Source A is less than 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

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
LES tag	FBD_COMPARE	structure	LES structure

-    Structured Text
Use the less than sign "<" as an operator within an expression. This expression evaluates whether sourceA is less than 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 LES instruction.

Example
If value_1 is less than value_2, set light_3. If value_1 is greater than or equal to value_2, clear light_3.

-    Ladder Diagram

-    Function Block

-    Structured Text
light_3 := (value_1 < value_2);


- Download to PDF

Read More »

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

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

Read More »