Mitsubishi Electric MELSEC iQ-R Series - Page 828

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7 APPLICATION INSTRUCTIONS
7.9 Real Number Instructions
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).
• 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
(SD0)
Description
3402H The value input to (s) is -0, a subnormal number, NaN (not a number), or .
3405H An out-of-range value is set to (s).
• The specified value is a negative number.
• The specified value is 0.
log ( ) ( )
(s)(s)+3 (s)+1(s)+2
(d)(d)+3 (d)+1(d)+2
Double-precision real number Double-precision real number