Hi Udo,
Many thanks for your helpful response.
Your reply above looks like a good start.
But I was wondering if it was possible to produce a function[time] on the x axis that would give the correct value at each time point.
Assuming the starting point is function[0*t] = 32400. Then for example the following would look like :-
function[1*t] = 57600,
function[2*t] = 90000,
function[3*t] = 129600
