Справочник Пользователя для Mitsubishi Electronics MELSEC -Q/L
7 APPLICATION INSTRUCTIONS
7.12 Special Function Instructions
639
7
Natural logarithm operation on floating-point data (single
precision)
precision)
LOG(P)
*1 Applicable for the Universal model QCPU, LCPU.
Processing details
• Returns the natural logarithm of the value designated by (S) taking (e) as base, and stores operation results at device
designated by (D).
• Only positive values can be designated by (S). (Operation cannot be performed on negative numbers.)
• When an input value is set using a programming tool, a rounding error may occur. For precautions, refer to Page 90
• When an input value is set using a programming tool, a rounding error may occur. For precautions, refer to Page 90
Operation error
• In any of the following cases, an operation error occurs, the error flag (SM0) turns ON, and an error code is stored into SD0.
*2 There are CPU modules that will not result in an operation error if -0 is specified. For details, refer to Page 88 Using single/double-
• Basic model QCPU: The serial number (first five digits) is "04122" or later.
(S): Data of which the natural logarithm is obtained or head number of the devices where the data is stored (real number)
(D): Head number of the devices where the operation result will be stored (real number)
(D): Head number of the devices where the operation result will be stored (real number)
Setting
data
data
Internal device
R, ZR
J\
U\G
Zn
Constant
E
E
Others
Bit
Word
Bit
Word
(S)
(D)
Error
code
code
Error details
Q00J/
Q00/
Q01
Q00/
Q01
QnH
QnPH
QnPRH QnU
LCPU
4100
The value specified in (S) is negative.
The value specified in (S) is 0.
The value specified in (S) is 0.
The specified device value is -0.
4140
The specified device value is not within the following range:
0, 2
0, 2
-126
| Specified device value | <2
128
The specified device value is -0, unnormalized number, nonnumeric, and
.
4141
The operation result exceeds the following range.
(when an overflow occurs)
2
(when an overflow occurs)
2
128
| Operation result |
Basic
Process
High
performance
Redundant Universal
LCPU
Ver.
Command
Command
LOGP
LOG
LOGP
LOG
S
D
S
D
32-bit floating-point
real number
real number
(
)
32-bit floating-point
real number
real number
+1
+1
S
D
S
D
log