1/16/2016 2:55 AM | |
Joined: 3/28/2010 Last visit: 9/12/2024 Posts: 1056 Rating: (213) |
The requirements to review reliability data for SIL rating of instruments (used extensively in oil & gas and the chemical industries for functional safety) have resulted in publication of some reliability data. https://cache.industry.siemens.com/dl/files/582/48694582/att_861923/v1/siemens_DSIII_4.pdf A quick search of the document did not reveal an MBTF number, but there are some failure numbers. Maybe you can find a colleague in the industries that use functional safety who can interpret the numbers for you (it's outside my scope). In answer to your question about heat/cool cycling conditions - my experience shows that exposure to elevated temperatures kills devices. Those devices that run close to or over the rated ambient or process temperature spec ratings have shortened lives. I have not found that heat/cool cycling at lower temperatures (day/night temps) to contribute to early failures. Given that, nothing lasts forever. |
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