ATAN

Arctangent

ATAN calculates the arctangent of the input variable (value ± 52707176) and writes the angle data in radians into the output variable. The function returns a value greater than -p/2 and smaller than p/2.

Parameters

Input

Unnamed input (REAL, LREAL): Input value between -52707176 and +52707176

Output

Unnamed output (REAL, LREAL): Output as input: arctangent of input value in radians

Error flags

sys_bIsOperationErrorHold (turns to TRUE and remains TRUE): if input variable does not have the data type REAL, LREAL or input variable ³ 52707176
sys_bIsOperationErrorNonHold (turns to TRUE for one scan): if input variable does not have the data type REAL, LREAL or input variable ³ 52707176
sys_bIsEqual (turns to TRUE and remains TRUE): if output variable is zero
sys_bIsCarry (turns to TRUE for one scan): if processing result overflows the output variable

Example

POU header

All input and output variables used for programming this function have been declared in the POU header. The same POU header is used for all programming languages.

	VAR
		input_value: REAL:=0.0;
			(*range -1 to 1*)
		output_value: REAL:=0.0;
			(*angle data radians -Pi/2 to Pi/2*)
	END_VAR

This example uses variables. You can also use a constant for the input variable.

LD body

The arc tangent of input_value is calculated and written into output_value.

BODY
    WORKSPACE
        NETWORK_LIST_TYPE := NWTYPELD ;
        ACTIVE_NETWORK := 0 ;
    END_WORKSPACE
    NET_WORK
        NETWORK_TYPE := NWTYPELD ;
        NETWORK_LABEL :=  ;
        NETWORK_TITLE :=  ;
        NETWORK_HEIGHT := 5 ;
        NETWORK_BODY
B(B_F,ATAN!,Instance,7,1,12,3,,?D?C);
B(B_VARIN,,input_value,5,1,7,3,);
B(B_VAROUT,,output_value,12,1,14,3,);
L(1,0,1,5);
        END_NETWORK_BODY
    END_NET_WORK
END_BODY

ST body

output_value:=ATAN(input_value);