EQ block

Short summary

Name	`EQ`
→POU type	→function
Category	Standard (safe), Compare
Conform to →IEC-standard	currently restricted IEC demands data type `ANY_ELEMENTARY` for the inputs, hence the following data types are demanded as well: `LTIME`, `WSTRING`, `WCHAR`, `LDATE_AND_TIME`, `LTIME_OF_DAY` and `LDATE`. Currently, these data types are not supported for the block.)
Graphical interface
Available since	version 1.0.0 (for Neuron Power Engineer) – initial variant version 1.11.0 (for Neuron Power Engineer) – enhancement: `DATE_AND_TIME` and `TIME_OF_DAY` for `IN1`, `IN2`, ... `IN16` version 1.91.0 (for Neuron Power Engineer) – enhancement: `STRING` and `CHAR` for `IN1`, `IN2` ... `IN16` version 3.8.0 (for library `Standard (safe)`): block provided in this library

Functionality

The block is a comparator regarding equality ("EQuals to").

Enter the values at the inputs, those values are to be compared. The block returns value TRUE (or an equivalent), if all values connected to the inputs are equal – hence, if: (IN1=IN2) & (IN2=IN3) & ... & (IN15=IN16)

Bitstring values (= ANY_BIT values; see →generic data type} are treated like unsigned →integer values by the block. This behavior is a specification according to the →IEC-standard.

Inaccuracies for floating-point numbers

Due to the internal representation of floating-point numbers (affects the data types REAL and LREAL) there might be inaccuracies when processing such values. Such inaccuracies might result in a not expected result when comparing such values.

Inputs, return value

	Identifier	→Data type	Description
Inputs:	`IN1`	`REAL`, `LREAL`, `USINT`, `UINT`, `UDINT`, `ULINT`, `SINT`, `INT`, `DINT`, `LINT`, `TIME`, `BOOL`, `BYTE`, `WORD`, `DWORD`, `LWORD`, `STRING`, `CHAR`, `DATE_AND_TIME`, `DATE` or `TIME_OF_DAY`	1st value
	`IN2`	`REAL`, `LREAL`, `USINT`, `UINT`, `UDINT`, `ULINT`, `SINT`, `INT`, `DINT`, `LINT`, `TIME`, `BOOL`, `BYTE`, `WORD`, `DWORD`, `LWORD`, `STRING`, `CHAR`, `DATE_AND_TIME`, `DATE` or `TIME_OF_DAY`	2nd value
	... (extensible until)
	`IN16`	`REAL`, `LREAL`, `USINT`, `UINT`, `UDINT`, `ULINT`, `SINT`, `INT`, `DINT`, `LINT`, `TIME`, `BOOL`, `BYTE`, `WORD`, `DWORD`, `LWORD`, `STRING`, `CHAR`, `DATE_AND_TIME`, `DATE` or `TIME_OF_DAY`	16th value
Return value:	–	`BOOL`

Input EN and output ENO are available when →calling the block. See "Execution control: EN, ENO" for information on input EN and output ENO.

See:

"Blocks for safe logic" whether this block is supported for developing safety-relevant applications.
"Highlighting safe logic in the FBD-editor" for the effects when using the block as a block for safe logic.

Example for usage within ST-editor

The calculated values are evaluated by using the Assert block.

FUNCTION_BLOCK ExampleToEq

VAR

      result1, result2 : BOOL;

   END_VAR

   result1 := EQ(IN1 := 1.0, IN2 := 2.0);

   result2 := EQ(IN1 := 1.0, IN2 := 1.0);

   Assert(result1 = FALSE);

   Assert(result2 = TRUE);

END_FUNCTION_BLOCK

When creating your application within the ST-editor, enter a call of a block by typing the text as requested by the syntax or use Content Assist.