Jesse Off napsal(a):
> A couple months ago we jointly commisioned a professional and
> independent H.A.L.T test (highly accelerated life testing) be run on
> our TS-7250 design with one of our customers to find out just how
> rugged our boards are. A link to the 32 page officially prepared
> report is at ftp://ftp.embeddedarm.com/halt.pdf. The operator at the
> facility was quite impressed with the board and said he's rarely seen
> anything so ruggedly built.
>
> Tests they ran:
> *) extreme high/low temperature runs
> *) rapid thermal tests (getting the board to about boiling temperature
> and then super cooling it with liquid nitrogen)
> *) vibration (G force) tests
> *) combined (vibrating while in hot/cold temps.. etc..)
>
> A few highlights:
>
> *) Even though the intention of the test was to test the board until
> they broke, they were unable to destroy a single TS-7250. Actually,
> the vibration table they were using started malfunctioning before
> anything on the board did. The operator had said a previous test on
> another board actually caused it to "explode" as parts of the board
> started flying off with high velocity.
>
> *) A +70degC rated TS-7250 board actually continues to work properly
> from -60degC(-76degF) to +110degC(230degF). At the high end
> temperatures, the epoxy inside the null modem cable started melting
> and seeping out yet the board continued to run fine. At the low end
> temperatures frost and snow was forming on the board. These
> temperatures were where the boards started exhibiting strange
> behaviors... once the temperature was brought back down between
> -60degC and 110degC, they snapped back to life without any permanent
> damage.
>
> *) Board was still holding together at 55 G rms. What we found was
> that if you are in a *extreme* high vibration environment, you
> probably want to solder down the power connections and use a dab of
> loctite on any DB9 screws (since they have a tendency to unscrew at
> extreme G force ratings), but otherwise the board will be fine. USB
> also is a non-industrialized connector (figures since it comes from
> the consumer PC world) and shouldn't be used in high vibration
> environments-- but everybody probably knows this.
>
> *) The fast temperature cycles caused *nothing* to go wrong. This is
> quite surprising as this is one of the most brutal things you can do
> to a board. Keeping the number of passive devices to a minimum and
> hand-routing the traces on the board paid off here.
>
> All in all, a very impressive result. I wish we could have tested one
> of those "embedded" PC motherboards (EPIC, mini-ITX, etc..) alongside.
> Most of those boards have large, heavy heatsinks/fans attached that
> would have been fun to watch cause the circuit boards to shatter or
> pull off the solder pads on the attached chips. Also, since they're
> not thermally stable enough to go without their heatsinks/fan at room
> temp, its likely an overtemp condition would result in thermal runaway
> and eventual permanent self-destruction.
>
>
Thanks for this info. I can report very good experience with TS7250 in
my application that works on Czech mountains. Whole winter works
without any problem. Some controllers was under 2m layer of snow.
Thanks
Dan
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