Slot points on schedule

[fbio]

We need to build a schedule y=log7(итьxить) Accordingly, there is a break point at x=0. In this case, Delphi (as did Exel) accepts, instead of zero, a very small number expressed through the Expont. Because of that, x=0, y=17.532 I'm trying to build a graph and make points of rupture, and I'm using 2 series. But the problem is, under certain x, the schedule is being built normally, but under others, either it's unsatisfactory, or the other way around, it's building a line to read the code. I'm writing like this, and it's not clear that:

begin
Series1.Clear;
series2.Clear;
StringGrid1.Cells[0,0]:='X';
StringGrid1.Cells[1,0]:='Y';
xn:=StrToFloat(Edit2.Text);
xk:=StrToFloat(Edit3.Text);
dx:=StrToFloat(Edit4.Text);
x:=xn;
i:=0;
repeat
y:=LogN(7,ABS(x));
i:=i+1;
StringGrid1.Cells[0,i]:= FormatFloat('0.000',x);
StringGrid1.Cells[1,i]:= FormatFloat('0.000',y);
StringGrid1.RowCount:=i;
if (x<0) then
series1.AddXY(x,y);
if (x>(abs(dx))) then
series2.AddXY(x,y);
x:=x+dx;
until x>xk+dx;
Chart1.visible:=true;
StringGrid1.visible:=true;
end;

[Demir]

1. In the area of the rupture point, dx is reduced (more than the first output module, the smaller it shall be).

2. Control value y:

   if y < -10 then y := -10;
   

   or

   if y < -10 then continue;
   

   Just don't forget the drilling. x♪

3. Change if(x > (abs(dx))) then ♪ if(x > 0) then