15-04-2016, 02:24 PM
Dorothy,
A detailed technical understanding of relays/circuits should not be required for M1. In your paper attempt, you have discussed many of the relevant points already.
Assume an aspect relay stuck up, it could permit a higher aspect than is permitted to be displayed. With a track, you can have a relay stick up showing clear when it is occupied, sticking down [showing occupied] is a RSF.
Re effects, design can mitigate, or magnify, the effects of failure. Poor component selection can do similar. Having a system running close to its limits [contact current, relay load] can also cause problems.
Mitigations could be sequential track occupation [showing tracks have picked and dropped in order], high reliability -proven- relays with non-stick contacts [this is a misnomer, less likely to stick is more apt], double cut circuits [mitigates against just one contact being 'stuck' but don't cure all being stuck], how about health checking the system [change in current loads etc], periodic replacement of at-risk relays... The paper asks for things that could be used - they answer could be a little out there or not very practical but as long as it isn't pie-in-the-sky!
Happy to discuss more fully at Signet in July if you're coming?
A detailed technical understanding of relays/circuits should not be required for M1. In your paper attempt, you have discussed many of the relevant points already.
Assume an aspect relay stuck up, it could permit a higher aspect than is permitted to be displayed. With a track, you can have a relay stick up showing clear when it is occupied, sticking down [showing occupied] is a RSF.
Re effects, design can mitigate, or magnify, the effects of failure. Poor component selection can do similar. Having a system running close to its limits [contact current, relay load] can also cause problems.
Mitigations could be sequential track occupation [showing tracks have picked and dropped in order], high reliability -proven- relays with non-stick contacts [this is a misnomer, less likely to stick is more apt], double cut circuits [mitigates against just one contact being 'stuck' but don't cure all being stuck], how about health checking the system [change in current loads etc], periodic replacement of at-risk relays... The paper asks for things that could be used - they answer could be a little out there or not very practical but as long as it isn't pie-in-the-sky!
Happy to discuss more fully at Signet in July if you're coming?
Le coureur