Tuesday, Nov 02, 2004 at 12:57
Jeff M
This situation is not remotely a parallel with today's kids having a natural affinity. That affinity is with the software - the programming. It is not how microprocessors work - kids are good at fixing computer software problems - but rarely if ever the hardware. But then hardly anyone is because the usual process is identify the crook board/s replace and re-progam. Like, increasingly, with cars except that cars are more complex.
But with cars, it's the hardware not the software that goes wrong. If that hardwear fails, a kid has as much chance of fixing it as a 90-year old plumber. In fact I'd probably back the plumber - at least he'll know that a good hit with a hammer may fix a crook connector.
As with Mike Harding I have a long history of designing and building very complex electronic equipment - including early computers. I also started and ran a chain of electronics magazines worldwide.
In earlier days electronic stuff used to be relatively easy to fix. Then it was not unlike vehicle engineering: separate bits did separate things and by identifying a crook one it was easy to solder in another.
These days have gone. Nowadays things are so complex that it is customary to replace a complete system - or at least major sub-system.
Re the relative reliability of space craft. Their design confirms rather than negates my concern. It is absolutely true that even the most modest laptop has far more processing
power than even recent manned space craft. Why? Because the latter deliberately use basic and totally tried and tested electronic technology. This has not remotely the performance of later stuff but it's more readily fixable.
The Apollo series used discretes transistor (electronics types call it 'TTL') at a time when microprocessors were begining to be used even in dishwashers. On the day Man first landed on the Moon I was working for Natronics (in Kingsgrove, NSW) I was looking at using microprocessors in taximeters. And a year later did.
Why did NASA choose to use TTL logic? Because it could be (and was) readily fixable in the field. To some extent that's what saved Apollo 13.
Unmanned craft use super-sophisticated technology - because whilst a loss is a major issue - no one is killed as a result. And, the results show this. Many are lost.
Ask yourself why, if electronics is so reliable and effective, why is it none to speak of used in the Humvee's go-making bits? It's certainly not because GM doesn't know about it - we were experimenting with printed circuit dashboards, multiplexed systems and electronic active
suspension way back in 1962.
What is interesting abut this debate is that the cautious are emerging as those who have worked in this field. And those who say it's all just fine appear to have not (that doesn't make the latter wrong or their views necessarily less than valid - but it's still interesting).
What I am basically saying (I think) is that if there are bits in vehicles intended to spend their lives off-road (and I repeat, I'm not talking about the odd week or two schlepping up the OTT and back) and if those bits will incapacitate the vehicle and cannot be fixed or bypassed - then, as with aircraft, they need to be duplicated.
Many
Forum members will have seen what can and does go wrong with vehicles on tag-alongs to remote parts. But to many up here, in the NT and outback SA and Qld, these tag along 'adventure' routes are routine driving. And often alone and in vehicles that rarely are serviced properly simply because the distance to and from the closest service centre can be half the recommended service interval.
It's a different scene.
I am also talking specifically and almost exclusively about Toyota Troopies, HiLuxes and 4.2 litre Nissan Patrols because, with respect, these are about the only vehicles that are KNOWN to be strong enough to withstand continuous outback working usage. The Taliban worked that out (even if their Hiluxes were petrol driven)!
Have a look at Broome outside the tourist season - there's hardly a vehicle there except Troopies and dual cab HiLuxes. My own Troopy was one or a row of 15 such (I counted them) outside the Post Office yesterday - and all with the identifying BM XXX number plates (that tourists believe let the shopkeepers know how much to charge!).
Collyn Rivers
AnswerID:
82718
Follow Up By: Mike Harding - Tuesday, Nov 02, 2004 at 14:16
Tuesday, Nov 02, 2004 at 14:16
Excellent post Collyn.
>But with cars, it's the hardware not the software that goes wrong.
>If that hardwear fails, a kid has as much chance of fixing it as a
>90-year old plumber. In fact I'd probably back the plumber at least
>he'll know that a good hit with a hammer may fix a crook connector.
I’m with you, my monies on the plumber :)
>These days have gone. Nowadays things are so complex that it is
>customary to replace a complete system - or at least major
>sub-system.
Exactly. And that is the design philosophy employed by Bosch et al. It makes no sense to have a highly trained electronics technician hanging around a motor vehicle dealers with a bucketfull of very expensive test gear for the occasions when the electronics blow up. Much more sensible to provide low tech. training to the vehicle automotive guys so that they diagnose to board level and do a board swap. Then send the board off to be repaired or thrown away.
>Re the relative reliability of space craft.
Two things: 1) as you say, life support systems will tend to use old technology because it’s tried and tested. Also because these systems take so long to design and test, by the time you’ve completed them the technology which was new when you started is now old. 2) Typically life support system will have three levels of redundancy, so if level one fails you have two backup system – not always (pacemakers may not) but many critical systems do.
>Unmanned craft use super-sophisticated technology
You should see some of the defence stuff these days! A-bloody-mazing! :)
>What is interesting abut this debate is that the cautious are emerging
>as those who have worked in this field.
Modern day electronics are astonishingly reliable, no question – BUT when they fail are usually irreparable without specialised equipment and knowledge. As someone else said “so is a conrod through the block” – quite true but the difference is I _must_ have a conrod and engine block but a remote area vehicle does not _have_ to have electronically controlled fuel injection or an O2 sensor etc. Why increase the number of critical systems? If _any one_ of them fails – you’re stuffed. This is really the nub of the thread: normally a vehicle is not a life support system but in remote regions it may be but manufacturers will _never_ want to acknowledge that for legal reasons and the fact that very few of their vehicles will fall into that category – but for those which do it’s a critical issue. And that’s why I would prefer not to have critical electronic systems in such a vehicle.
Mike Harding
mike_harding@fastmail.fm
FollowupID:
341785
Follow Up By: GUPatrol - Tuesday, Nov 02, 2004 at 15:19
Tuesday, Nov 02, 2004 at 15:19
Ditto!
Well said guys...
One more thing for Jeff M, the paper clip is to bridge the ECU to output the codes through the dash. However the error codes are only for inputs (ie: sensors). you can have a component failure which is not covered by the ECU's monitoring.... Or you may get a code such as "knock sensor failure" because there is a leak in the exhaust manifold which is letting air in and the oxigen sensor reports mixture too reach so it leans it up and the knock sensor reports knocking, as a result the ECU goes into limp home mode (which as you say) provides some redundancy until you turn the engine off, once off it will not start again until cleared...
Having worked in the industry, I can give you thousands of examples, some vehicles (all brands) sometimes sit at dealerships until the problem is fixed, sometimes they wait for sensors to be delivered overnight until it is replaced and then the ECU reports another one faulty just because the problem wasn't there in the first place!!
Not to mention intermitent faults...!
William
FollowupID:
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Follow Up By: GUPatrol - Tuesday, Nov 02, 2004 at 15:20
Tuesday, Nov 02, 2004 at 15:20
Sorry that should have read "mixture too rich" not reach...
FollowupID:
341789
Follow Up By: ToyMotor - Tuesday, Nov 02, 2004 at 20:37
Tuesday, Nov 02, 2004 at 20:37
Collyn wrote:
I also started and ran a chain of electronics magazines worldwide.
Aah - you're THAT Collyn Rivers! The name rang a bell, that's for sure - interesting to hear what you've up to! And by the way, excellent posts - I couldn't agree more, I own what might be one of the last non-turbo 78 series Troopies delivered in Aust., got it in August 2001. I've been thinking I might keep it till it's 20years old, like my dear departed HJ60....
Cheers
FollowupID:
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