Steema Central

Posted: **Tue May 16, 2006 4:18 am**

Hi,

I was wondering if TeeChart 5 can handle SPC charting, if not what is the most feasible and cost effective solution?

thanks,

charbin

[/b]

Posted: **Tue May 16, 2006 7:33 am**

Hi charbin,

Yes, this can be achieved using TeeChart 5. Below there's the code of a Delphi example. You shouldn't have much problems porting it to TeeChart Pro v5 ActiveX.

Calculating and charting the Upper and Lower limits of an SPC Quality Control series.

This example includes formulae to calculate the SPC upper and lower limits. The Chart displays 2 series, one with the number of "good" parts and another with the percent of "bad" parts. With these two Series, the example calculates two values: the upper and lower limits. These limits are displayed using another two series.
Correctness of calculation depends very much on your particular country rules.

Code: Select all

unit QualityControl;
{$I TeeDefs.inc}

interface

uses
  {$IFNDEF LINUX}
  Windows, Messages,
  {$ENDIF}
  SysUtils, Classes,
  {$IFDEF CLX}
  QGraphics, QControls, QForms, QDialogs, QExtCtrls, QStdCtrls, QComCtrls,
  {$ELSE}
  Graphics, Controls, Forms, Dialogs, ExtCtrls, StdCtrls, ComCtrls,
  {$ENDIF}
  TeeProcs, TeEngine, Chart, Series;

type
  TFormQuality = class(TForm)
    Chart1: TChart;
    Good: TLineSeries;
    Bad: TLineSeries;
    Upper: TFastLineSeries;
    Lower: TFastLineSeries;
    Panel1: TPanel;
    Memo2: TMemo;
    Panel2: TPanel;
    Label1: TLabel;
    Label2: TLabel;
    UpperEdit: TEdit;
    LowerEdit: TEdit;
    procedure FormCreate(Sender: TObject);
    procedure UpperEditChange(Sender: TObject);
    procedure LowerEditChange(Sender: TObject);
  private
    { Private declarations }
    UpperLim : Double;
    LowerLim : Double;
    Procedure CalculateSPC(GoodSeries,BadSeries:TChartSeries);
  public
    { Public declarations }
  end;

implementation

{$IFNDEF CLX}
{$R *.DFM}
{$ELSE}
{$R *.xfm}
{$ENDIF}

{ Calculate the upper and lower limits }
Procedure TFormQuality.CalculateSPC(GoodSeries,BadSeries:TChartSeries);
Var Sum,SumN,
    tmp,Aux,
    LCP,
    LCN,
    NumTotal,
    Percent    : Double;
    t,N        : Integer;
Begin
  UpperLim:=0;
  LowerLim:=0;
  Sum:=0;
  SumN:=0;
  N:=0;
  for t:=0 to GoodSeries.Count-1 do
  begin
    Percent:=(BadSeries.YValues[t]*GoodSeries.YValues[t]/100.0);
    NumTotal:=GoodSeries.YValues[t]+Percent;
    if NumTotal>0 then
    Begin
      Sum:=Sum+Percent/NumTotal;
      SumN:=SumN+NumTotal;
      inc(n);
    end;
  end;
  LCP:=Sum/n;
  LCN:=SumN/n;
  tmp:=(LCP*(1-LCP))/LCN;
  if tmp>0 then
  Begin
    Aux:=3*Sqrt(tmp); { <-- 3 by square root }
    UpperLim:=100.0*(LCP+Aux);
    LowerLim:=100.0*(LCP-Aux);
  end;
End;

procedure TFormQuality.FormCreate(Sender: TObject);
var t:Integer;
begin
  Good.Clear;
  for t:=0 to 19 do Good.Add(800+Random(200),'',clTeeColor);

  Bad.Clear;
  for t:=0 to 19 do Bad.Add(4+Random(4),'',clTeeColor);

  CalculateSPC(Good,Bad);

  UpperEdit.Text:=FormatFloat('#.0000',UpperLim);
  LowerEdit.Text:=FormatFloat('#.0000',LowerLim);

  Chart1.LeftAxis.SetMinMax(0,1100);
  Chart1.RightAxis.SetMinMax(0,10);
end;

procedure TFormQuality.UpperEditChange(Sender: TObject);
var tmp : Double;
begin
  try
    tmp:=StrToFloat(UpperEdit.Text);
  except
    on Exception do exit;
  end;
  Upper.Clear;
  Upper.AddXY(0,tmp);
  Upper.AddXY(19,tmp);
end;

procedure TFormQuality.LowerEditChange(Sender: TObject);
var tmp : Double;
begin
  try
    tmp:=StrToFloat(LowerEdit.Text);
  except
    on Exception do exit;
  end;
  Lower.Clear;
  Lower.AddXY(0,tmp);
  Lower.AddXY(19,tmp);
end;

initialization
  RegisterClass(TFormQuality);
end.

Steema Central

Can TeeChart 5 Support SPC Charting?????

Can TeeChart 5 Support SPC Charting?????