I am working with an individual that has placed a bunch of small MM420s in buckets. He has Hand/Auto stations at the motors. I am responsible for the automatic mode side as i am doing the PLC, HMI, and Profibus. These drives are on Profibus and this is how they are controlled in Automatic mode.
He has a two-position switch that enables two circuits.
Circuit-1 is a standard Start/Stop to the drive by switching on, and off Dig in-2
Circuit-2 switches on a relay that triggers the local/remote function on the drive via Dig in-3
The local stop button is also in line with this and will de-energize Dig in-3 but only as long as the button is pressed. If the unit is on auto mode and an individual by the motor wants to stop it, it only stops as long as he has his finger on the button. What we need is for that action to stop the motor permanently. What we also need to do is have the drive do it, and not rely on the PLC to stop the unit.
I know why this is happening, the PLC has the start bit on, and when the button is pressed Dig in-3, and Dig in-2 are de energized. When you release the button they come back on.

This switch is mainly for maintenance personnel to work on the motor and be able to bump it as needed to do checks. So at times the PLC may be down for maintenance as well so the station has control of the drive. But around here, we like to have Stop buttons, stop the motors no matter what mode we are in.
So, if in auto mode we need this drive to stop and stay stopped, not just when the button was depressed.
I was tinkering with adding a circuit that employs an enable, or an external trip. Some of these units already employ Dig in-1 as an enable, so perhaps I can place a contact in line with that, and on the others with no Dig in-1 place a new contact and trigger the enable of the drive.

If that input comes off momentarily, will the motor stop and stay stopped?
If you have any better ideas, please let me know.