update on this case. System for this device had to be only pl C
We can use Nx1p2 cpu for "safety" systems. But we have to make external safety calculation and fulfill standard requirements. Also we need to have external Test channel.
In my case there is only one safety related analog input. We will use external Analog value switch, to fulfill standard 13849 category 2 requirements (picture in attachments).
We also make sistema risk assessment for the system. If mttfd-value (mean time to dangerous failure) is high enough we can use nx1p2-cpu.
Long story shot. If you use two differend systems to monitor and control the safety system, it might be possible to use non safety rated systems.
Hope so this helps you in the future!