Short summary

Name	`SQRT`
→POU type	→function
Category	IEC-block, Numeric, block with internal error diagnostic
Conform to →IEC-standard	no restrictions
Graphical interface
Available since	version 1.18.0 (for logi.CAD 3) version 3.1.0 (for library `Standard`) – For inputs of data type `REAL`, the optimized `float` variant of the C-runtime is used. Compared to previous versions , it is possible that (marginal) other results are returned within the threshold range of the block.

Functionality

The mathematical function for the square root is called: The block returns the square root of the value connected to the inpu t .

Inputs, return value

	Identifier	→Data type	Description
Inputs:	`IN`	`REAL`, `LREAL` (corresponds to →generic data type `ANY_REAL`)	input
Return value:	–	`REAL`, `LREAL` (corresponds to →generic data type `ANY_REAL`)

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 .

Internal error diagnostic for block

The block checks the value connected to the inpu t before it is executed.
If the value is < 0.0, the output ENO of the block is set to value FALSE (or an equivalent).

Example for usage within ST-editor

PROGRAM Test
   VAR
      result : REAL;
   END_VAR
   result := SQRT(IN := 4.4);    (* The variable 'result' evaluates to '2.097618'. *)
END_PROGRAM

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.