I have a Y axis running with ac servos at 600IPM, everything works perfectly, the repeatability is dead on, except it seems like I loose steps at power down which results in a descrepancy of a consistant 0.0005 inches of loss. It is very small and not a probl;em as long as I reset the axis to its home position at startup, but it would be nice to shut it dow and be able to re-start in exactly the same position.
In other words, when I start up, I have to jog +0.0005 inches and shut down to reboot so that I am at my prefereed machine zero. Any idea what would cause this loss of 0.0005 in. at shut down? It is extremely consistant.