Mitsubishi Electric MELSEC iQ-R Series Programming Manual page 828

Processing details
• These instructions calculate the logarithm using natural logarithm (e) of the value specified by (s), and store the operation
result in the device specified by (d).
(s)+3 (s)+2 (s)+1
log (
Double-precision real number
• Input a positive value only. (No negative value can be calculated.)
• If the operation result is -0 or an underflow occurs, the operation result turns out to 0.
• When an input value is set using the engineering tool, a rounding error may occur. Refer to the following for the precautions
on setting input values using the engineering tool.
Page 49 Precautions
Operation error
Error code Description
(SD0)
The value input to (s) is -0, a subnormal number, NaN (not a number), or .
3402H
3405H An out-of-range value is set to (s).
• The specified value is a negative number.
• The specified value is 0.
7 APPLICATION INSTRUCTIONS
826
7.9 Real Number Instructions
(s) (d)+3
) (
Double-precision real number
(d)+2 (d)+1 (d)
)