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[IP] Re: "Static Electricity" (LONG)

I asked for and received the "Animas Overview of Technology" and this 
is quite an impressive document.  If everyone remembers back when 
there were only 2 pump companies, a little firm from Pennsylvania 
decided to find out the best of both current pumps and make one even 

The Animas engineering philosophy is for no compromise: "that any 
component or subsystem, no matter how reliable, how rugged, or how 
well tested, can fail."  Acknowledging this, Animas engineers 
incorporated a number of levels of redundancy in the design for the 
most critical functions.  And further, they used dissimlar redundancy 
checks.  Triple redundant FETs control infusion.  Two to be in an 
"on" state, one to be in an "off" state.  Thus if both of the "on" 
FETs were to fail by shorting, it would require the failure of the 
"off" FET to an opposite state (open-circuit mode) at the very same 

"Critical variables are stored twice, in their normal binary form and 
an inverted binary form.  Examples of critical variables are the 
basal and bolus dosage and the corresponding number of encoder steps 
the encoder counter would count.  These variables in their normal and 
inverted forms are added.  If no corruption of these variables 
occurs, the the digits add to zero.  If one digit becomes corrupted, 
the sum is not zero, resulting in an immediate shutdown of the system 
and sounding of the alarm."

"microprocessor sends out a signal every 833 milliseconds, If the 
microprocessor fails to send this signal the system is shut down."

"code is broken up into multiple modules that are connected in a 
single loop task. The navigation throughout this loop must occur in a 
specific order.  Each module test to see that all of the previous 
modules in the task loop have preceded it in the proper order." " In 
addition to this, there is an additional safeguard to ensure that any 
given module does not call itself so there is no re-entry"  or " the 
system shuts down and the alarm sounds"

"linear detector monitors the motion of the cartridge.  If the 
cartridge moves more than the appropriate amount, the system shuts 
down and an alarm sounds"

"if the microprocessor were to fail, an independent clock circuit 
would trigger an audible alarm"

Oh, and as far as Static Electricity goes, the Animas was tested to withstand:

A contact discharge of 8,000 volts (electrostatic discharge)

An air discharge of 15,000 volts (electrostatic discharge)


Submersion in water at a 12 foot depth for 24 hours

Vibration: swept sine vibration (in all 3 axes) of values at a 
frequency 3 to 8 Hz, displacement: 7.5 mm, and 4 cycles each direction

Vibration: swept sine vibration (in all 3 axes) of values at a 
frequency 8 to 300 Hz, acceleration 2g, 4 cycles each direction

Mechanical Shock: withstand a drop of 1 m in each axis to a hardwood surface

RFI, magnetic fields (per IC 601-1-2 and IEC 601-2-24, para. 36202)\

Ambient temperature range +5C to +40C

Relative humidity 20% to 90% including condensation

Atmospheric pressure 10 psi to 16 psi

Now if I could just survive that sort of torture!      ;>)
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