I abandoned it altogether and went a different route, to answer your question the problem happened all the time even if the drives were powered up before the controller, I never did find out how the controller "sensed" the encoder, I assume it would be a current draw from the encoder. I thought about connecting it to the DRO scales but that can be problematic and the scales are single ended and would need a differential converter so I fitted another control instead (Fagor 8055m) which accepts different encoder inputs and by changing a parameter switches off the encoder sense, something CS-Labs should consider, otherwise they are a great controller. Cheers Dave