I don't think it is. Each subsystem would have a small processor infront of it, that you communicate with over SPI, it would enforce the different safety parame

I don't think it is. Each subsystem would have a small processor infront of it, that you communicate with over SPI, it would enforce the different safety parameters and do the local control. Things like setting PID values, monitoring and setting voltages, etc. It would ignore values that exceeded its predetermined operating envelope for the subsystem. It would have cost about an extra 1 or 2 dollars to implement this technique in the UPS.