You are using a ub1
Have you setup (cut / soldered) the jumpers on the ub1 correctly
Have a look at page 18 &19 of the ub1 manual
AO1 has a default setting which is not analog output.....
Also check your setting for the screenset are you using UB1 or UC300eth (another jumper on the board)
UB1 Owner's manual E1.5 Rev0
http://www.cncroom.com/downloads/UB1%20 ... 0E15R0.pdf*4, *5 and *12 are the ones you want to read and understand around page 18/19 in the ub1 manual