----------
From: Christopher, Tom
To: daemon; cavers; techdiver
Subject: Re: Rebreather experience
Date: Wednesday, August 02, 1995 2:04PM

Bill;

Having spent the major part of my adult life developing, testing and 
fielding computer based weapon systems I know for a fact that there will be 
bugs in the software and hardware associated with any software/firmware 
based system rebreather or otherwise. I do not know what capabilities the 
manufactures have for testing their product, I'm going to make a guess 
though that they, in all probability, do not have a very sophisticated test 
capability and that they will not be able to test all possible paths the 
software can take nor do they have exhaustive digital hardware test 
capabilities. There will be problems with these systems and any buyer is in 
fact performing what we in the Air Force call Development Test and 
Evaluation (Does the term test pilot come to mind) so if it is your intent 
to own one of these systems be sure to stay in contact (close contact) with 
the manufacture.

Cecil
 ----------
From: daemon
To: cavers; techdiver
Subject: Re: Rebreather experience
Date: Wednesday, August 02, 1995 12:59PM

Roderick,


> The BioMarine CCR155 is electronically controlled. But, the elecrtronics
> can crap out completely and you can operate the unit manually. Any
> rebreather that is worth purchasing must have that capability.

I don't agree with this premise.  Perhaps for all of the units that are
currently out on the market, this is true, but that reflects improper design
of the electronics.

From what I've seen of the published details of the units, none of them has
sufficient redundancy or a sufficiently redundant design.  This is the kind
of life critical application that requires algorithm proving, fault-tolerant
hardware of the 'committee of three' type of design, as well as redundant
gas paths.

None of the units that I've seen (and I've probably not seen all of them) 
has
those features.  If the electronics are done correctly, they cannot 'crap 
out
completely' - So I think I'm gonna wait for one that is done right.

Apologies to any units I've missed which have such features, if you do, I'd
be interested in hearing about it!

 --
/***************************************************************************/
/* William E. Sadler  | email:  sadler_b@bs*.bs*.bl*.co* 
               */
/*                    |         batchmo@cr*.co* 
                           */
/* Divers Down! [\]   | CI$:    71005,1241 
                                */
/*                    | POTS:   (404) 332-2314 
                            */
/***************************************************************************/
/* Keep your Honor, be Bold, and remember: 
                                */
/* The only things in the middle of the road are yellow stripes and 
       */
/* squished possums. 
                                                      */
/***************************************************************************/
 --
Send mail for the `techdiver' mailing list to `techdiver@terra.net'.
Send subscription/archive requests to `techdiver-request@terra.net'.

Navigate by Author: [Previous] [Next] [Author Search Index]
Navigate by Subject: [Previous] [Next] [Subject Search Index]

[Send Reply] [Send Message with New Topic]

[Search Selection] [Mailing List Home] [Home]