We evaluated ASI safety systems a short while ago.
Personally I am sceptical about reliability. It seems to me (at least from the way it was described) that the sysstem sends multiple messages over the bus, and if an error is detected it will fail safe, i.e it will trip or estop.
Now we have been using ASI bus for machine I/O for about 2 years now. It's simplicity and ease of adding extra I/O is great. But it's not without it's problems. One problem I experienced a while back was a single I/O module that would very occasionally fail to communicate over the bus properly. When I say very occasionally I mean once or twice a day. It was a bugger of a fault to fix. Substituting a new module did not fix it. Disconnecting a lot of other modules on the bus did not fix it. It turned out to be a simple grounding fault in the end, we had grounded the I- of one of the sensors, and because the I+ and I- are derived from the ASI bus, it didn't like that.
So my point is, had we been using ASI safety bus in that instance, we would have had a spurious estop occurring once or twice a day. Not many customers would tolerate that.
Also, we supply machines for use all round the world. A lot of our customers are particularly cautious about safety systems, and is one area they usually examine in detail. Not one that I have yet mentioned it to would accept ASI safety bus. They all want a traditional hard wired circuit to a tried and tested make of dual circuit safety relay.
It's certainly a system to keep an eye on for the future, but at the moment it doesn't have sufficient industry acceptance.