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>> Well, we'd like to check that the blood samples we're storing actually
>> about this fact, urgently.
>
> is informed? Would you trust a 20 quid meter from Maplin then?
My point exactly - it seems to have nothing to do with how reliable the
device is, only the subjective feeling it gives you in your head knowing
that "I paid lots of money for this, therefore it must be really
reliable". Which isn't terribly scientific...
>> I'm guessing a temparature sensor that actually *works* at
>> temparatures that low is going to cost a tad more than your average
>> room thermometer,
>
> Not really, thermocouples are cheap (like a fiver) and measure down to
> below -100 degrees.
Well, maybe you have to be slightly more careful that, e.g., the
insulator on the wire doesn't become as brittle as glass when it gets
too cold or something.
somebody has to check it won't break or something when it gets that damn
cold.
>> It seems
>> the only reason for the higher price is that this is a critical
>> device, so the suppliers know they can charge the Earth and we will
>> pay it. We have to.
>
> Or the fact that there is a much lower chance it will break or
> mal-function.
Why? Do they actually *do* something different with it? Does the
hardware itself have any actual physical differences to a cheap model?
a several thousand percent markup, and started marketting it at a
different market segment.
On the other hand, I remember researching printers one time. I ended up
looking at two printers. Both Hewlett Packard. Both print at 1200dpi.
Both have built-in network support. Both do duplex printing. Etc. But
one printer was about 10x the price of the other. Why?
The answer is a little number hidden at the bottom of the page
somewhere: "duty cycle". One printer said 1,000 pages/month, the other
said 100,000 pages/month. And you know what? We ended up buying both
printers, and one is still working to this day, the other one we
eventually threw away because it just kept breaking so often.
In this case, it seems paying 10x the price does, in fact, get you a
device which is *physically different*. I don't know if they use thicker
plastic for the drive gears or what, but the more expensive printer was
far more reliable. The cheap one is basically designed to sit in your
house. [Actually, I have one at home. It works just fine. But then, I
hardly ever print anything!] Put that printer in a busy office and it
just can't cope.
>> The mass spectrometers we have here all say "for research and
>> development only; not for diagnostic procedures" on them. I can't
>> imagine why - it's a mass spectrometer! Either it measures masses
>> reliably, or it doesn't. If it does, you can use it for anything you
>> like. If it doesn't, it's a worthless piece of equipment. So... why
>> the sticker?!
>
> Because they don't guarantee it will work reliably the whole time. For
> them to guarantee that, they would need to do lots of expensive testing
> on every unit, probably design in lots of redundant systems, use more
> expensive components that have longer lifetimes, use better assembly
> methods etc.
Well, you're the engineer. But I wonder - if a mass spectrometer that
does one you *can* use for diagnostic procedures cost?! o_O
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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On Thu, 15 May 2008 15:18:18 +0200, "scott" <sco### [at] scott com> wrote:
>
>Or the fact that there is a much lower chance it will break or mal-function.
>A simple example I can think of is that the connector where the thermal
>probe plugs in mal-functions somehow so that the electronics thinks that the
>temperature is -90 when really it is only -70. Or some solder joint on the
>circuit board wasn't made completely correctly and messes up some other
>reading in an undetectable way once the temperature and humidity get to a
>certain value. There are all sorts of failure mechanisms that needs to be
>checked and fixed somehow, and that costs lots of money.
You need to ensure that the cold joint (or in this case the hot joint)
is compensated properly for changes in the ambient temperature.
For medical/critical equipment you need certification to ensure
compliance with the laws of the country. And not just UK laws it
should comply with the laws of the registered country. In your case I
imagine that is the USA.
--
Regards
Stephen
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On Thu, 15 May 2008 13:52:37 +0100, Invisible <voi### [at] devnull> wrote:
>Stephen wrote:
>
>> Is the equipment and software certified? Because that adds to the
>> cost.
>
>Not by the supplier, I don't *think*. Certainly *we* will be regularly
>checking it against an ISO standards-certified reference instrument
>[which really *is* insanely expensive]. But I don't *think* the
>suppliers actually provide any such guarantees - I'm not sure...
Buy the cheapest and that is what you get. And is your secondary
calibrator regularly checked against a primary calibrator?
--
Regards
Stephen
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> My point exactly - it seems to have nothing to do with how reliable the
> device is, only the subjective feeling it gives you in your head knowing
> that "I paid lots of money for this, therefore it must be really
> reliable". Which isn't terribly scientific...
Surely you check out the specification before buying something? It will
include details about *how* reliable it is, with real numbers, and under
what conditions it has been tested in. Something you buy from Maplins won't
have this.
> somebody has to check it won't break or something when it gets that damn
> cold.
Exactly - someone has to check - and that costs money.
> Why? Do they actually *do* something different with it?
Yes, it is designed to be more reliable, and they test it to prove this so
they can write it in the specification of the device.
> Does the hardware itself have any actual physical differences to a cheap
> model?
Probably, if you're lucky you could get a *really* reliable one from Maplin
that lasted for 1000 years without any problems. *Lucky* being the key word
here, try explaining to someone's family that they died because some monitor
failed, you can't say "we were unlucky".
> several thousand percent markup, and started marketting it at a different
> market segment.
And put in place processes for guaranteeing the reliability of the product,
at least testing each one and working with their suppliers to ensure that
correct procedures are followed to avoid any unreliabilities. You see those
news stories about paint from China causing problems? Without controlling
your suppliers properly stuff like that happens - and if you are supplying
something you claim to be suitable for critical processes, you are in deep
trouble if you allow your suppliers or your own processes to screw up.
> The answer is a little number hidden at the bottom of the page somewhere:
> "duty cycle". One printer said 1,000 pages/month, the other said 100,000
> pages/month. And you know what? We ended up buying both printers, and one
> is still working to this day, the other one we eventually threw away
> because it just kept breaking so often.
Exactly.
> In this case, it seems paying 10x the price does, in fact, get you a
> device which is *physically different*. I don't know if they use thicker
> plastic for the drive gears or what, but the more expensive printer was
> far more reliable. The cheap one is basically designed to sit in your
> house. [Actually, I have one at home. It works just fine. But then, I
> hardly ever print anything!] Put that printer in a busy office and it just
> can't cope.
The same way that buying a 20 quid power drill from B&Q is fine if you only
use it once a month to drill a few holes. But if you are a builder and you
use it 20 times a day, it's going to break after a week. Which is why you
invest in a way more expensive model. OK so if you bought the cheap one it
*might* last for several months, but it's not worth the risk if you really
need your drill to work every day.
> Well, you're the engineer. But I wonder - if a mass spectrometer that you
> one you *can* use for diagnostic procedures cost?! o_O
Medical equipment is extremely expensive, precisely because there is so much
at risk when things go wrong. The companies that make this stuff need to do
a huge amount of testing and robust design, way above what most other
industries require. It all costs money.
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And lo on Thu, 15 May 2008 14:32:47 +0100, Invisible <voi### [at] devnull> did
spake, saying:
Heh I love it when you get ranty about the price of mission-critical stuff.
Here's a story I was told I forget the exact measurements and prices but
still -
A women approaches a company that make bespoke wooden doors for a new
front door. She can't buy an off-the-rack for £100 because they're two
inches too narrow, they quote her a price of £250. She blows her top
shouting "You're charging me £150 for those two extra inches" and storms
off never to return.
The moral, of course, is that she wasn't be charged an extra £150 she was
being charged £250 to have workmen create for her a uniquely sized door
from scratch.
--
Phil Cook
--
I once tried to be apathetic, but I just couldn't be bothered
http://flipc.blogspot.com
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Invisible wrote:
> but beyond that I don't see why it would need to cost more.
In the US, I'd say it's because if the device fails and all your blood
samples warm up and you lose $1M of revenue, you could reasonably expect
to sue the company that made the device to get your money back.
It's called "incidental damages" here.
If that's what you're paying for, then that's a big part of the price
difference. If the company doesn't warrant that the device will actually
work, then I couldn't say. Around here, a $20 thermometer is going to
have a warranty that says "If it breaks, you might be able to get your
$20 back, but that's about it."
> If it doesn't, it's a worthless piece of equipment. So... why the
> sticker?!
Liability control. If you can't tell when it's broken, and you overdose
someone because your mass spectrometer misread how much drug was in the
solution, it's much more expensive than if you (say) ruin an
experimental car engine by putting the wrong mix of fuel in it.
--
Darren New / San Diego, CA, USA (PST)
"That's pretty. Where's that?"
"It's the Age of Channelwood."
"We should go there on vacation some time."
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Invisible wrote:
>
> every 15 minutes. If they go outside a preset range, an alarm goes off.
> How much would *you* suggest such a system costs?
A freaking *lot* if it's calibrated so it can for sure measure up to
0,1C and not just show that way and the service contract includes yearly
(oslt) re-calibrations.
> Apparently all the suppliers we could find were charging 5 figures for
> something that will do what we want. Seems absurd to me, but... mission
> critical, gotta have one, gotta be up and running before date X...
Mission critical: you take 5 UPS's, 5 PC's, 5 sensors and wire them up
separately. If all five from even the cheapest hardware break down
simultaneously enough, you're having the worst luck of the world
already. OTOH, then you won't have A) service contract, B) scheduled
re-calibrations, C) calibration at the first place.
> Well, you'd hope so... but as I say, I wasn't really involved in the
> process. I believe the hardware was all much the same, so they went with
> the cheapest option from a supplier who could actually supply on time.
You weren't involved -> it's not your call -> you shouldn't stress about it.
--
Eero "Aero" Ahonen
http://www.zbxt.net
aer### [at] removethiszbxtnetinvalid
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>> somebody has to check it won't break or something when it gets that
>> damn cold.
>
> Exactly - someone has to check - and that costs money.
Well that at least makes sense. You're paying money *for* something.
>> Why? Do they actually *do* something different with it?
>
> Yes, it is designed to be more reliable, and they test it to prove this
> so they can write it in the specification of the device.
This somewhat implies that normal stuff is designed to be UNreliable. ;-)
>> Does the hardware itself have any actual physical differences to a
>> cheap model?
>
> Probably, if you're lucky you could get a *really* reliable one from
> Maplin that lasted for 1000 years without any problems. *Lucky* being
> the key word here, try explaining to someone's family that they died
> because some monitor failed, you can't say "we were unlucky".
I'm just wondering whether they actually did anything different at all
for the extra money, that's all.
it'll take up to 15 days to arrive. But actually it arrives within 12
hours. And it still arrives within 12 hours. Do they actually do
anything different? Or is it just a tax on stupidity?
On the other hand, consider the printers example. Clearly something *is*
actually different, because the printers really do perform differently.
So in this case, you *are* getting something for your money.
I'm not sure which category this temparature monitor falls into.
>> Well, you're the engineer. But I wonder - if a mass spectrometer that
>> HELL does one you *can* use for diagnostic procedures cost?! o_O
>
> Medical equipment is extremely expensive, precisely because there is so
> much at risk when things go wrong. The companies that make this stuff
> need to do a huge amount of testing and robust design, way above what
> most other industries require. It all costs money.
Heh. And I thought a device that costs more than my house (!!) was
already expensive. ;-)
[Seriously - WTF does a mass spectrometer even have in it? It's just an
empty tube, some vacuum pumps, an electrode and some magnets. So is my
TV! Well, apart from the vacuum pumps anyway... And yet, my TV doesn't
cost more than a small housing estate. Wuh??]
BTW, wasn't there some famous disaster with a device for radiotherapy
that accidentally overdosed a few people?
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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Eero Ahonen wrote:
> You weren't involved -> it's not your call -> you shouldn't stress about
> it.
Oh, hey, I'm not *stressing* about this! I couldn't care less. ;-) I'm
merely curios about the design of it...
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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On Thu, 15 May 2008 22:10:07 +0100, Orchid XP v8 <voi### [at] devnull>
wrote:
>
>>> Why? Do they actually *do* something different with it?
>>
>> Yes, it is designed to be more reliable, and they test it to prove this
>> so they can write it in the specification of the device.
>
>This somewhat implies that normal stuff is designed to be UNreliable. ;-)
He said "more" reliable. Have you heard of tolerances?
--
Regards
Stephen
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