SQRT block

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 Neuron Power Engineer) 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 input.

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 input 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.