I thought you were on to something there, the low active for direction was ticked and for steps was not -so I'd obviously used that to sort out directions. I ticked both, but then nothing worked so I unticked them both and used the "reverse" to sort out directions. Unfortunately running a test program I'm still experiencing the error. It is in all axis, just depends which one has worked most during the program as to which has the largest error. max speed is set to 1000 and acceleration to 50 -do these sound reasonable figures (mm per minute). I have the step pulse set to 5, but what about the direction pulse (it's at the default of 0 now) -I couldn't find any mention of this parameter in the set up guides. I'm wondering if I could be losing one step each time an axis changes direction.