E-Stop's no longer required to be Hard-Wired, Actually I saw a similar system a couple of decades ago and wondered how it passed muster.
http://www.laird-controls.com/e_stop.html?SessionGuid=d2379d48-2f9d-4219-bb36-01c5bbda5b84
Obviously when signal is lost it must go into E-Stop.
Max.

 

Well, they do call it a 'Safe-E-Stop(tm)'. That's different than an official OSHA approved 'E-Stop'. One client of mine had to stop calling his big red button an 'E-Stop' because it didn't meet the codified requirements which included hard-wired and separate from any 'intellegent' control that may go whacky, as well as accessibility provisions and a lot more.

I always specified safety or hard-limit related stuff to be brutal - dropping power to the motors etc. maybe with notification to the controller but hard-wired. I'm not up to date on what the current regs. are for an 'E-Stop' but would be uncomfortable with the Safe-E-Stop as a last-chance safety. Got too old, seen too much.

 

Dang... A rule I thought inviolable.

 

This is from NFPA79.
Max.

 

I would argue that the remote e-stop does not meet the requirements of 13.7.3.

With the remote e-stop attached to an operator’s waistband, unintentional operation is not only likely - but in my opinion, inevitable.