help to connect alarm signal driver hbs86h

Yes, I understand you but I don't have input for each driver. I don't care that linuxcnc tells me which driver is wrong. I just need it to come to a stop when that happens.

The problem is that when the driver fails the red LED does not light up. On the other hand, if I disconnect the driver from the bob, the red LED does turn on. I am doing all the tests with a single driver and the only input I have free.

you have to collect signals from all amplifiers via a relay and connect it to one input  of your Bob. As a bonus, I would connect LEDs to show who is in pain.
 

The problem is that when the driver fails the red LED does not light up. On the other hand, if I disconnect the driver from the bob, the red LED does turn on. I am doing all the tests with a single driver and the only input I have free.

And in that case i would try to set Alarm level parameter. Maybe your AMP show foults in different way. In this case you have to simple invert Relay connection and joint.0.amp-fault-in