With a servo system cutting the power to the drivers if limits are activated is for safety in case you have a servo run away due to encoder loss, but cutting the enable will also work in this situation as well.


Quote Originally Posted by JAZZCNC View Post
Well I don't agree with Killing power because Limit trip isn't an emergency situation it's a positional error so no need to Kill power just Halt movement. SO I would have limits tied to the Enable signal on drives and Inform the Controller of a Limit breach.
This way you don't damage expensive tooling when the spindle grinds to halt inside of material because power is Cut.! Machine is just halted from continuing and you can recovery safely by lifting tooling out of material then reversing off the Switches using tempory overide.

E-stop is an emergency situation to the operator and this is when you want power stopped but often positional errors ie: limits are not life threatening or dangerous to user only potential machine damage and the Limit's prevent this in most cases.

I did wounce upon time think "Kill every thing" but experience as taught me it's not needed where limits are concerened and it's more a pain in the arse, esp with short travels with fast accelerating machine and expensive at times with unnecessary tool damage.