Omron CQM1H - PROGRAM Programming Manual page 393

Floating-point Math Instructions
Description
Flags
368
ATAN(––) calculates the arc tangent of a 32-bit floating-point number and
places the result in the specified result words. (The arc tangent function is the
inverse of the tangent function; it returns the angle that produces a given tan-
gent value.)
When the execution condition is OFF, ATAN(––) is not executed. When the
execution condition is ON, ATAN(––) computes the angle (in radians) for a
tangent value expressed as a 32-bit floating-point number in S+1 and S and
places the result in R+1 and R. (The floating point source data must be in
IEEE754 format.)
–1
TAN S+1
R+1
The result is output to words R+1 and R as an angle (in radians) within the
range of – π /2 to π /2.
The following diagram shows the relationship between the input data and
result.
ER: Indirectly addressed EM/DM word is non-existent.
(Content of *EM/*DM word is not BCD, or the EM/DM area boundary
has been exceeded.)
ON if the source data is not recognized as floating-point data.
EQ: ON if both the exponent and mantissa of the result are 0.
Source (32-bit floating-point data)
S
Result (32-bit floating-point data)
R
R
S: Input data (tangent)
R: Result (radians)
Section 5-24