Natural Logarithm Floating-Point Math (SIMATIC)

  Numeric (IEC)
Inputs/Outputs Operands Data Types
IN VD, ID, QD, MD, SMD, SD, LD, AC, Constant, *VD, *AC, *LD REAL
OUT VD, ID, QD, MD, SMD, SD, LD, AC, *VD, *AC, *LD REAL

Memory Ranges ENO Errors Instruction Support for S7-200 CPUs SIMATIC/International Mnemonics
The Natural Logarithm instruction performs the natural logarithm of the value in IN and places the result in OUT. To obtain the base 10 logarithm from the natural logarithm, divide the natural logarithm by 2.302585 (approximately the natural log of 10).

Error Conditions that Set ENO = 0:

SM1.1 (overflow), SM4.3 (run-time), 0006 (indirect address)

This instruction affects the following Special Memory bits:

SM1.0 (zero); SM1.1 (overflow); SM1.2 (negative)