New build with recycled parts on a ridiculous budget 120cm*60cm work area

[Neale]

I'm not sure about the AM882s, but with the software you can configure the EM806 so the fault output is active when ok (i.e. switched on), and goes inactive on fault (i.e. open circuit). That's how I configured my EM drives, which would allow you to loop through all the fault outputs and create a failsafe circuit.

You are probably right about the AM882 also being software-configurable, but it looks as if getting a cable to be able to reprogramme the 882 and making all the configuration software work is another can of worms (judging by the experience of other people). I know it shouldn't be, but I didn't need to use the fine-tune facilities available through software and could manage with just the DIP switch options, so I chose not to change the factory setting for the alarm. That way I avoided any need to play with the configuration software. My thinking in this case was that normally you would be a bit more paranoid about NC connections, but here all the connections are hard-wired inside the box and so rather more reliable than anything going via plugs and sockets and around the machine itself.

Your recommendation is the better one; I chose to use a very slightly inferior option, and one that would be easier for the OP to use. Connecting in the fault outputs at all is a big leap forwards!