Valerio,

Can you please provide a screenshot of your charts demonstrating the issue?  If I understand your requirement correctly, you want to have the same interval (and range?) for each Y-axis.  This implies to me that you would naturally run the risk of some series becoming unreadable as you mentioned, so I am not sure what can be done. 

Either way, a screenshot showing the issue, along with your own notes indicating what you WANT it to be, will be very helpful.

Thanks,

Thanks a lot: it's OK
Now I have another question.
I have three line charts on the same page and I need to show multiple series for each chart.
Series are known only at runtime so I have to add series in code behind.

I need to show (it's a graphical requirement) YAxis line labels at the SAME position for every chart:
I suppose I have to manage the interval along with  max and min values.
The formula should be: (max -min) / desired interval.
I tried to hard code, for example, a max value at 100, a min value at 1, and an interval at 20 for every chart: the three charts have Y lines layed on the same position correctly.
The problem is that the range of the series may differ a lot; so if a chart, for example, has a max value of 1.5 and a min value of 0.5, and the other chart as a max value of 100, the line series of the first chart are compressed in an unreadable minimal space.
The question is: how can I set a fixed interval for every chart so that  Y lines can appear on the same position? Setting a  global max value for every chart doesn't work because of the above problem.

Thanks
VALERIO