function AM_PM(Zeit: TTime): string; 
var nk: double; 
begin 
  nk := Frac(Zeit); 
  if nk = 0.5 then Result := 'Mittag' else 
    if nk < 0.5 then Result := 'Vormittag' else 
      Result := 'Nachmittag'; 
end; 
 
// Beispielaufruf 
 
procedure TForm1.Button1Click(Sender: TObject); 
begin 
  showmessage(AM_PM(StrToTime('3:00 PM'))); 
end;