Mark,
Hey, glad you like the averaging routine. I was wondering if you could do me a favor? I made a modification to it a little while ago. You know how the least sigificant digit will "wobble" back and forth between 2 numbers? It's half-way between 2 numbers and it can't quite figure out which one it should be. Well, the modification adds hysterisis to the averaging routine to eliminate that.
None of my current projects use the averaging, so I haven't had a chance to test it yet. I gave it to someone else, but never heard back from him. I assume that means it worked.
If you have some extra time, maybe you could try this out.Code:'**************************************************************** '* Name : Average_Hyst.pbp * '* Author : Darrel Taylor * '* Date : 7/19/2005 * '* Version : 3.0 * '* Notes : Modified to use Hysterisis * '* : Use as an INCLUDE file * '**************************************************************** ' This routine will keep a "Running Average" of 10-bit Analog Values ' Instead of adding a bunch of values together and then dividing by the number ' of samples, it averages each sample into the final result immediately. ' This eliminates the need for 32 bit math. ' To allow it to "Catch up" to large changes, set the FAspread to an ' acceptable range. ' Simply place the new number in VALUE and GoSub Average ' The Average (with Hysterisis) will be returned into the same variable VALUE '---- [ User Options ] --------------------------------------------------------- HystLevel CON 7 ' 7 = .7 of the Least Significant Digit ' Valid HystLevel is from 6 to 13 AvgCount CON 16 ' = Number of samples to average. For best response ' times, keep AvgCount as small as you can FAspread CON 50 ' = Fast Average threshold +/- ' FAspread should be larger than the worst possible ' noise in the A/D conversion. '------------------------------------------------------------------------------- AVGchanged VAR BIT ' 1 indicates that the Average Value has changed ' you have to clear this bit after using it ADavg VAR WORD ' Stores the current Average ADhyst VAR WORD ' Stores the current Value for Hysterisis Value VAR WORD ' Input / Output variable to be averaged spread CON FAspread * 10 ' adjust spread *10 for Hyst. GOTO OverAverage ' -=-=-=-=-=-= Average Analog values -=-=-=-=-=-=-=-=-=-= Average: Value = Value * 10 ' Scale value up for hysterisis IF Value = ADavg Then NoChange ' if they're the same, nothing to do IF ABS (Value - ADavg) > spread OR Value < AvgCount Then FastAvg IF ABS (Value - ADavg) < AvgCount Then RealClose ADavg = ADavg - (ADavg/AvgCount) ' Subtract 1 samples worth ADavg = ADavg + (Value/AvgCount) ' Add in the new sample portion GoTo AVGok FastAvg: ' Catch up to the changing value ADavg = Value ' Set Average to the current value GoTo AVGok RealClose: ' Reduce the sample size when ADavg = ADavg - (ADavg/(AvgCount/4)) ' the average and the sample are ADavg = ADavg + (Value/(AvgCount/4)) ' "Real Close" AVGok: IF ABS (ADavg - ADhyst) > HystLevel then ' If it changed > HystLevel +/- ADhyst = ((ADavg + 5) / 10) * 10 ' Round ADavg to get new Value AVGchanged = 1 ' Indicate that Average changed ENDIF NoChange: Value = ADhyst / 10 ' Scale the result down Return OverAverage: '---------------------------------------------------------------
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