Hi Suneet,
Setting the Auto scaling to true will make the axis to get automatically scaled to fit the data present on that axis. So whether you get equal scaling for X and Y axes depends on the data on those axes i.e., if the lengths of the range of data present on the X and Y axes are equal then the scaling for both the axes will be equal, otherwise it will not be equal.
To get the equal scaling for X and Y axes, set the Auto scaling of both the axes to false and manually set the range of the axes so that the length of the range for both the axes is same. You can do this at design-time if you know the range of the data, or else you can do this at run-time by setting the Minimum and Maximum properties of the axis accordingly or using the SetMinMax method present on the axis.
Thanks,
Mohammed Haseeb|Measurement Studio|National Instruments