The minimums and maximums of the data shown are likely to be very different;
however I would like them to have the same 0 line.  There are positives and
negatives (sometimes only on the primary axis) so my 0 is often not lining
up (i.e. 0 on the primary axis is lower than 0 on the secondary usually).
Is there a way to make sure that the two Y axis share the same 0 line but
with different scales?

Peter