Thanks for the replies Craig and TP,

Craig, it doesn't sound like it's going to be as straight forward as I'd hoped. Thanks for your elaboration of what actually happens to performance of the servo when setting a global torque limit, rather than my simplistic interpretation of the same. I don't particularly want an impotent spindle servo with M3, at low speeds torque is already an issue.

TP, I'm not sure how to modify the code behind the stop or estop button, please feel free to elaborate.

Cheers
Dave