Logix5000 Controllers General Instructions - SLAC Confluence

Advanced Math Instructions (LN, LOG, XPY) 553FBD_MATH StructureInput Parameter Data Type DescriptionEnableIn BOOL Enable input. If cleared, the instruction does not execute and outputs are not updated.Default is set.Source X REAL Base value.Valid = any floatSource Y REAL Exponent.Valid = any floatOutput Parameter Data Type DescriptionEnableOut BOOL The instruction produced a valid result.Dest REAL Result of the math instruction. Arithmetic status flags are set for this output.Description:If Source X is negative, Source Y must be an integer value or a minorfault will occur.The XPY instruction uses this algorithm: Destination = X**YThe controller evaluates x 0 =1 and 0 x =0.Arithmetic Status Flags:Arithmetic status flags are affected.Fault Conditions:A Minor Fault Will Occur If Fault Type Fault CodeSource X is negative and Source Y is not an 4 4integer valueExecution:Relay LadderConditionprescanrung-condition-in is falserung-condition-in is truepostscanActionThe rung-condition-out is set to false.The rung-condition-out is set to false.The controller takes Source X to the power of Source Y and places the result inthe Destination.The rung-condition-out is set to true.The rung-condition-out is set to false.Publication 1756-RM003I-EN-P - January 2007