Leadshine MD882 Driver E-Stop

[electrosteam]

I am re-commissioning a newly purchased Bridgeport clone turret mill using EMC and MD882 to Nema 34 4-terminal steppers.

As acquired, there is no E-Stop facility.

The MD882 has an ENABLE input which is advised in the manual as a "usually not connected" feature, without any description of how it might be used.

Can the Enable input be used to E-Stop the drive ?

Thanks in advance,
John.

[neilw20]

Yes.
It will remove power from the steppers.
It is best to use an electrically latched safety relay that E-S, limits or computer cause it to drop out.
Keeping it all in hardware with no computer controlling the safety function is smart.
Using a watchdog signal from the computer to keep the safety relay latched is even smarter.
If the computer hangs, the relay drops out.
Devising a power up sequence to latch the relay requires some planning, and if the operator has to hold a button during referencing this is a good move. (IMHO)

[electrosteam]

Neil,
Does the driver simply stop pulsing with current at zero, or does it do some sort of powered braking action ?

I have never operated a CNC mill, so I have no idea how far a spinning stepper/ballscrew might coast from full speed with power off.

Your comments on safety are well-founded.
I will incorporate an absolute power-off state to all drives and spindle for manual adjustments around the mill.

John.

[neilw20]

No braking action. Quite the opposite.
When disabled I believe cuirrent is removed from the stepper, and hence the will be no detent torque.
If you want torque to remain then you need to remove the drive signal.
Some Z axis, if not counterbalanced will run down if disabled, so consider the best action to take.
If you have a tacho signal from the spindle and it stalls, issuing an E-S from detecting a stalled cutter is a good way to stop the feed continuing with the cutter stopped.
There are many things, some subtle, to consider, and implement to make a machine reliable and safe.

[electrosteam]

Neil,
Contacted Leadshine and got an answer in 1 day from Paul, an Applications Engineer.

Paul confirmed you get a coasting stop when ENABLE is reset (0 V dc).

Paul did not add any comments on how achieve the quickest stop.
Your comment on removing the drive signal to maintain torque is probably the answer, I will investigate further.

Thanks, John.