Mitsubishi MELSEC-Q/L Programming Manual page 537

Program Example
(1) The following program seeks the natural logarithm of the value "10" set by D50, and stores the result at D30 and D31.
[Ladder Mode]
[List Mode]
Step Instruction
[Operation]
D50
b15
1
10 10
MOV BIN value
7.12.24 LOGD, LOGDP Natural logarithm operation on floating-point data
(Double precision)
7.12.24
LOGD, LOGDP
LOGD
LOGDP
: Data of which the natural logarithm is obtained or head number of the devices where the data is stored (real number)
S
: Head number of the devices where the operation result will be stored (real number)
D
Internal Devices
Setting
Data
Bit Word
––
S
––
D
Function
(1) Returns the natural logarithm of the value designated by
designated by .
D
S +3 S +2 S +1
log
(
64-bit floating-point
real number
(2) Only positive values can be designated by
(3) When the operation results in -0 or an underflow, the result is processed as 0.
Sets data used for natural
logarithm operation (
Converts the operation data
into a 32-bit floating-point real number (
Executes natural logarithm operation (
Device
Conversion to
D41
b0
2
floating-point
1 0
FLT 32-bit floating-point
real number
Command
Command
J \
R, ZR
Bit
S D +3 D
) (
64-bit floating-point
real number
. (Operation cannot be performed on negative numbers.)
S
)
1
D40 D31
LOG operation
3
2 . 3 0 2 5 8 5
LOG 32-bit floating-point
real number
High
Basic
performance
LOGD
LOGDP
U \G
Word
––
––
taking (e) as base, and stores operation results at device
S
+2 D +1 D
)
LOGD, LOGDP
)
2
)
3
D30
Process LCPU
Redundant Universal
S D
S D
Constants
Zn Other
E
––
1
2
3
4
4
6
7
8
––
––
535