Thanks, this will help me convince them that we can use an SBC and do
not need to buy $2,500 RTUs. It doesn't take a rocket scientist to
understand the difference in cost between 100 SBCs and 100 RTUs!!!!!!!
Yes, there is a little more signal conditioning work to be done, but
not that much.
On 4/13/06, Jesse Off <> wrote:
> 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.
>
>
> //Jesse Off
>
>
>
>
>
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--
Dr. Don W. Carr
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Guadalajara, Mexico
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