Natural Exponential 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 Exponential instruction performs the exponential operation of e raised to the power of the value in IN and places the result in OUT. The Natural Exponential can be used in combination with the Natural Logarithm to raise any real number to the power of another real number, including fractional exponents. That is, X raised to the Y power can be computed as EXP (Y*LNX).

Examples:

5 cubed = 5^3=EXP(3*LN(5))=125

The cube root of 125 = 125^(1/3)=EXP(1/3)*LN(125))=5

The square root of 5 cubed = 5^(3/2)=EXP(3/2*LN(5))=11.18034...

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)