How to reduce deceleration time of spindle

[Aiph5u (Aiph5u (not affiliated with Onefinity))]

Hey Tom @tjp52,

@tjp52

It’s easy to test the change to see if it’s working as expected. Just select the MDI tab and enter ‘M3 S10000’ and press ►. This will accelerate the spindle to 10,000rpm. Check your VFD and your buildbotics displays to verify the speeds are the same. Press ■ and the spindle should decelerate to a complete stop within about 6 seconds or less. Test various speeds just to confirm everythings ok. The spindle may not always display the exact speed you’ve entered but it should be within a very few rpm of the value entered on the MDI tab.

That refers to a normal stop command. But does this also apply when you assign an input to the function 8 Free Stop or 43 Emergency Stop, as discussed here with Daniel @PwnCNC?

According to IEC 60204-1, to meet the requirement for an emergency stop, which is finally reaching Safe Torque Off (STO) which is the case for Stop categories 0 and 1, requires that the spindle is electrically cut from power in the VFD, so it is usually left coasting in the final stage of emergency stop. Braking would mean that it is not cut from the VFD as the spindle (which acts as an induction generator then) would need to deliver its deceleration current to the internal brake chopper. This would only meet the Stop category 1 if it is ensured that the spindle is reaching the Safe Torque Off (STO) requirement at the end of the emergency stop procedure.