Short summary

Name	`IS_LIMIT`
→POU type	→function
Category	IEC-block, SelectEnh
Conform to →IEC-standard	not defined in IEC-standard
Graphical interface
Available since	version 1.35.0 (for logi.CAD 3)

Functionality

The block checks whether a value would be limited to defined limits (minimum and maximum value): MIN(MAX(IN, MN),MX) != IN Hence, this block informs whether the LIMIT block would limit the value.

You connect a value at input IN. If the LIMIT block would limit this value, the block IS_LIMIT returns the value TRUE (or an equivalent). The LIMIT block would limit the value, if the value of IN is > than the maximum value connected at input MX or if value of IN is < than the minimum value connected at input MN.
If the value of IN is within the defined limits or it is equal to one of the limits, the block IS_LIMIT returns the value FALSE (or an equivalent).

Special cases (see under "Example for usage within ST-editor" ) : If the minimum value is > than the maximum value, the block IS_LIMIT always returns the value TRUE (or an equivalent).

Inputs, return value

	Identifier	→Data type	Description
Inputs:	`MN`	`REAL`, `LREAL`, `USINT`, `UINT`, `UDINT`, `ULINT`, `SINT`, `INT`, `DINT`, `LINT`, `TIME`, `BOOL`, `BYTE`, `WORD`, `DWORD`, `LWORD`, `DATE_AND_TIME`, `DATE` or `TIME_OF_DAY`	minimum value
	`IN`	`REAL`, `LREAL`, `USINT`, `UINT`, `UDINT`, `ULINT`, `SINT`, `INT`, `DINT`, `LINT`, `TIME`, `BOOL`, `BYTE`, `WORD`, `DWORD`, `LWORD`, `DATE_AND_TIME`, `DATE` or `TIME_OF_DAY`	value
	`MX`	`REAL`, `LREAL`, `USINT`, `UINT`, `UDINT`, `ULINT`, `SINT`, `INT`, `DINT`, `LINT`, `TIME`, `BOOL`, `BYTE`, `WORD`, `DWORD`, `LWORD`, `DATE_AND_TIME`, `DATE` or `TIME_OF_DAY`	maximum 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.

Example for usage within ST-editor

PROGRAM Test
	VAR
		result1, result2, result3, result4 : BOOL;
	END_VAR
	result1 := IS_LIMIT(MN := 5, IN := 99, MX := 100);       (* The variable 'result1' evaluates to 'FALSE'. *)
	result2 := IS_LIMIT(MN := 5, IN := 2, MX := 100);        (* The variable 'result2' evaluates to 'TRUE'. *)
	result3 := IS_LIMIT(MN := 5, IN := 105, MX := 100);      (* The variable 'result3' evaluates to 'TRUE'. *)
	result4 := IS_LIMIT(MN := 100, IN := 2, MX := 5);        (* The variable 'result3' evaluates to 'TRUE'. Reason: value for 'MN' > value for 'MX' *)
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.