Logix5000 Controllers General Instructions - SLAC Confluence

546 Advanced Math Instructions (LN, LOG, XPY)Natural Log (LN)The LN instruction takes the natural log of the Source and stores theresult in the Destination.Operands:Relay LadderOperand Type Format DescriptionSource SINT immediate find the natural log of this valueINTtagDINTREALDestinationSINTtagtag to store the resultINTDINTREALStructured Textdest := LN(source);Use LN as a function. This function computes the natural log of sourceand stores the result in dest.See Appendix B for information on the syntax of expressions withinstructured text.Function BlockOperand Type Format DescriptionLN tag FBD_MATH_ADVANCED structure LN structureFBD_MATH_ADVANCED StructureInput Parameter Data Type DescriptionEnableIn BOOL Enable input. If cleared, the instruction does not execute and outputs are not updated.Default is set.Source REAL Input to math instruction.Valid = any floatOutput Parameter Data Type DescriptionEnableOut BOOL The instruction produced a valid result.Publication 1756-RM003I-EN-P - January 2007