positioning motor

I am using a MDC2460 controller in closed loop position relative mode with a hal sensor on AIN2. I want my script:

while true
currentpos = getvalue(_AIC, 2)
print( "desiredAnalog", desiredAnalog, "\n")
print("current position ", currentpos, "\n")
' wait(50)
if ((currentpos >= (desiredAnalog + 10) or currentpos <= desiredAnalog -10)) then
print("setting position \n")
setcommand(_G, 1, desiredAnalog)
wait(100)
end if
end while
to position the motor at desiriedAnalog, in this case 450. what I get is no movement although I the values from the print say I should;
desired position 450, current position -447.

I this mode shouldn't the setcommand(_G, 1, desiredAnalog) tell the motor to go to position 450?