Thankyou Joachim,
I have got something working. I probably should of been neater with a flow control statement, but work ok. (I actually have 10 possible parameters, but have shortened it for here)
The script works for Australian standards,
Maximum Riser Height = 190mm
Minimum Riser Height = 115mm
Maximum 2 x Risers + Going = 700mm
Minimum 2 x Risers + Going = 550mm
!Master Script
smax1 = stairheight/0.190
smin1 = stairheight/0.115
smax = int(smax1)+1
smin = int(smin1)
ropt1 = stairheight/smax
ropt2 = stairheight/(smax+1)
ropt3 = stairheight/(smax+2)
ropt4 = stairheight/(smax+3)
DIM risers[]
ii=0
if ropt1 > 0.115 and (2*ropt1)+going>0.550 and (2*ropt1)+going<0.7 then
ii=ii+1
risers[ii]=str("%0mm",ropt1)
endif
if ropt2 > 0.115 and (2*ropt2)+going>0.550 and (2*ropt2)+going<0.7 then
ii=ii+1
risers[ii]=str("%0mm",ropt2)
endif
if ropt3 > 0.115 and (2*ropt3)+going>0.550 and (2*ropt3)+going<0.7 then
ii=ii+1
risers[ii]=str("%0mm",ropt3)
endif
if ropt4 > 0.115 and (2*ropt4)+going>0.550 and (2*ropt4)+going<0.7 then
ii=ii+1
risers[ii]=str("%0mm",ropt4)
endif
!Parameter Script
values "riserheight" risers