position tracking

i want to go to 50 rotation in forward direction then come back to 0 position and then go to -50 position repeatedly

i wrote this script but it is not working.....



dim a as integer
dim b as integer
dim c as integer
dim d as integer

top:

a = 4000000
b = 4000000
c = 4000000
d = 4000000


while a
setconfig(_P, 2, 50)
a--

end while


while b
setconfig(_P, 2, 50)
b--

end while


while c
setconfig(_P, 2, 50)
c--

end while

while d
setconfig(_P, 2, 50)
d--

end while

goto top

!G command also not working

my controller config is attached pls find attachment