Paul Rudin wrote:
>
> > # Random vibration: 0.75g zero-to-peak, 10Hz to 500Hz, 0.25 oct/min
> > sweep rate (operating); 1.5g zero-to-peak, 10Hz to 500Hz, 0.5 oct/min
> > sweep rate (nonoperating)
>
> I don't really understand what these are saying.
>
"Operating" or"nonoperating" = whether its switched on or not (which
suggests that the hard drive is the main potential problem
"Random vibration" = vibration that has a statistically random waveform
(amplitide vs time)
"0.75g" = 0.75 times gravitational acceleration (which is 9.81m/s/s)
"zero to peak" = the amplitude lies between 0 and 0.75g (as opposed to
-0.75 to + 0.75)
"Hz" = cycles / second, the repetition rate or 'frequency' (of the
excitation, in this case)
"10Hz to 500Hz" = the frequency content of the 'random' vibration
(which is obviously not completely random, but a signal synthesised to
only contain energy between10 Hz and 500Hz)
"0.25 oct/min sweep rate" = one quarter of an octave (one octave =
doubling in frequency) per minute i.e. the frequency doubles in 4
minutes
Which is maybe why you didn't understand it, nor me (fully), as it
would be more usual to either spec. a random excitation (of a given
bandwidth) for a given time, or a sine wave excitation sweep from X Hz
to Y Hz over a given time - oh well, at least I've got that off my
chest
And the relevant bit? IMHO, in a pannier you would be unlikely to
crack the screen unless excessive local pressure was applied (use foam
padding) or trash the hard drive (if padding is used) - but a USB stick
or portable drive would be a better option (if you have a PC at either
end of the commute). BTW I have always considered a back pack as a less
agressive (vibration) environment for fragile goods (up to the point
where you drop it on the ground) as your body acts as a nice isolation
system from all that nasty road induced vibration.