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5-21-19 LOGARITHM: LOG(468)
(468)
LOG
S
R
Ladder Symbol
Variations
↑
LOG(468)
Operand Data Areas
S: First source word
CIO, G, A, T, C, #, DM
R: First result word
CIO, G, A, DM
When the execution condition OFF, LOG(468) is not executed. When the execu-
tion condition is ON, LOG(468) computes the natural logarithm for the 32-float-
ing-point content of S and S+1, and places the result in R and R+1. The opera-
tion is executed with 2.718282 taken as the base (e).
R+1
R
S
Source (floating-point data, 32 bits)
S+1
Result (exponent, floating-point data,
32 bits)
log
e
If the absolute value of the result is greater than the maximum value that can be
expressed for floating-point data, the Overflow Flag (A50009) will turn ON and
the result will be output as
±
R
.
Relation Between Input Data and Result
R
S: Input data
R: Result
Precautions
S and S+1must be non-negative floating-point data.
Note Refer to page 101 for general precautions on operand data areas.
Flags
ER (A50003):
S and S+1is a negative number.
S and S+1is not floating-point data.
The content of a
*
DM word is not BCD when set for BCD.
EQ (A50006):
The exponent and mantissa of the result are 0.
N (A50008):
The result is a negative number.
OF (A50009):
The absolute value of the result is greater than the maximum
value that can be expressed for floating-point data.
UF (A50010):
OFF when the computation is executed.
Description
Floating-point Math Instructions
Section 5-21
Summary of Contents for CVM1D
Page 462: ...SYSMAC CVM1D Duplex System Programmable Controllers Operation Manual Revised August 2001...
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