I hadn't thought of the possibility that the driver might remove motor voltage if not enabled. I can't see anything specific about this in the manual - going to have to actually test the hardware. I take the point about motor braking but I was influenced by a number of comments on this forum that you should not trust motion controller firmware for safety-critical functions like e-stop. Not entirely sure why not as we trust it to move each axis correctly and recognise limit switch inputs but there we are. So IF you don't trust the firmware and IF chopping power to the drivers will not have immediate effect, how do you stop the machine quickly? I'm particularly interested in avoiding damage if one of the slaved axis motors stalls. The manual does say that on stall detect, power is removed from the motor.