FMEDA sheet not picking more than 1 DCoverage

medini_1028110577

Hi,

When one has multiple Safety mechanisms assigned against SPF or LPF, medini is not able to derive any SPF/LF coverage nor can it calculate the SPF residual FIT or LF FIT .

I am told that as a result, the user needs to manually calculate and enter it.

For my kind of project, this isn't just practical as i dont see how i can manually do this for up to 1000 parts (perhaps up to 2000 or more failure mode occurrences).

Can i get a script that can do this?

medini_1023909254

Hi Ona,

that behavior is consistent with the ISO standard, which requires to evaluate each entry. medini can not derive the combined coverage in case of multiple combined safety mechanisms, because it is not known whether the mechanisms are completely independent or depend somehow on each other. Moreover, in fact you would really have to look at each individual failure mode of a safety related component and check whether the default coverage by the SM is also applying to the failure mode or whether there is a higher/lower coverage (cf. the appropriate flow charts in Part 5 and Part 10).

On the other side, in case you have a justified coverage value for a fixed combination of safety mechanims, you can also include it into your SM configuration as a separate entry - e.g. you have an entry in the configuration which is called SM1&SM2 combined. In the DC Worksheet you would then instead of multiple SM just use the SM1&SM2 combined as single entry - which puts the default coverage value of the combination into the Worksheet.

Best regards,

Eckhardt