Delta Electronics DVP15MC11T - Page 162

Chapter 8 Logic Instructions
8_
 Precautions for Correct Use

The input variable is not allowed to omit. An error will occur during the compiling of the software if
the input variable is omitted. But the output variable is allowed to omit.

The output value of Out is -π/2 if the input value of In is -∞. The output value of Out is π/2 if the input
value of In is +∞.
 Programming Example

The data types of variables ATAN_In and Out1 are REAL and LREAL respectively. The value of
Out1 is 0.785398163397448 if the value of ATAN_In is 1.0 when ATAN_EN changes to TRUE. The
value of Out1 is -0.785398163397448 as ATAN_In is -1.0.
 Variable 1
Variable name
Data type
Current value
ATAN_EN BOOL TRUE
ATAN_In
REAL
1.0
Out1
LREAL
0.785398163397448
 Variable 2
Variable name Data type Current value
ATAN_EN
BOOL
TRUE
ATAN_In
REAL
-1.0
Out1
LREAL
-0.785398163397448
 The program
1
ATAN
EN ENO
In Out
ATAN_EN
ATAN_In Out1
8-91