[SystemSafety] Baseline Safety Assessment for a Linux-based OS to SIL 3 /ASIL D

[Prof. Dr. Peter Bernard Ladkin]

On 2025-05-08 14:46 , Derek M Jones wrote:
>  I looked at some other exida
> functional safety assessments and they were similarly impenetrable:

I don't agree. These are all examples of what exida does (amongst other things). They look at a 
device and tell you it is suitable for use in a situation with specific safety requirements (namely 
in the implementation of a safety function with those requirements).

I've been reading these things for a decade and a half and it's clear to me what they say. p2 (in 
particular the bold-font parts) contains the key certificate.

> https://www.emerson.com/documents/automation/functional-safety-certificate-functional-safety-assessment-report-micro-motion-4200-coriolis-flowmeter-en-9295638.pdf 
>
> https://www.emerson.com/documents/automation/functional-safety-certificate-assessment-3051smv-multivariable-transmitter-en-792748.pdf 

> https://www.scatts.co.uk/datasheets/420768?desc=Worldwide-Exida-Functional-Safety-Assessment
> https://www.exida.com/images/upload_13/Rosemount_11-02-57_R002_V1R2_IEC_61508_Assessment.pdf

These are documents bestowing a safety certificate on specific devices. The bold font on p2 says 
exactly what requirements exida is certifying the device for.  And the next bit says that the 
manufacturer may use the exida SIL 3 logo for/on the device.

That is exactly what such a general assessment to the concepts of 61508 can say and, in my opinion, 
ought to say.

PBL

Prof. Dr. Peter Bernard Ladkin
Causalis Limited/Causalis IngenieurGmbH, Bielefeld, Germany
Tel: +49 (0)521 3 29 31 00