Microprocessor controlled washing machines
The Technical Manager
controlled timer and an LED or phosphorescent display instead of the
traditional mechanical timer.
Why is it that washing machines produced nowadays continue to use
mechanical timers when microprocessor timers would be cheaper. Infact
virtually no washing machines have microprocessor timers anymore.
Is it to do with reliability. Washing machines vibrate hard and harsh
vibrations are not good for solder joints, but then mechanincal timers
are precision components themselves. Or is it to do with customers not
liking a digital interface and prefer to turn a knob instead.
B
"The Technical Manager" <tec...@niobiumfive.co.uk> wrote in message
news:3AC4A69D...@niobiumfive.co.uk...
Kevin Aylward
"The Technical Manager" <tec...@niobiumfive.co.uk> wrote in message
news:3AC4A69D...@niobiumfive.co.uk...
> controlled timer and an LED or phosphorescent display instead of the
> traditional mechanical timer.
> Why is it that washing machines produced nowadays continue to use
> mechanical timers when microprocessor timers would be cheaper. Infact
> virtually no washing machines have microprocessor timers anymore.
>
Indeed. I recently bought a new washing machine with a mechanical timer. Any
one with electronic control was outrageously priced.
Kevin Aylward , Warden of the Kings Ale
ke...@anasoft.co.uk
http://www.anasoft.co.uk - SuperSpice "Cheap, No Shit!",
GUI xspice, an affordable unlimited component, mixed-mode Windows simulator
with Schematic Capture, waveform display, FFT's and Filter Design.
Opinions of my employer are not necessarily indicative of my own
Oscillators don't, amplifiers do"
Neon John
a) the mechanical timer is more reliable
and
b) the mechanical timer is cheaper.
BTW, you can buy a machine with a microprocessor if you want and can
afford it. Maytag's Neptune line. Be ready to part with a couple
thousand dollars for the set and be ready for problems. The Neptune
digital controls are eating Maytag alive on warranty claims
according to what I hear from the Maytag engineers and customer
service people whose offices are across the street.
John
--
John De Armond
johngdDO...@bellsouth.net
http://personal.bellsouth.net/~johngd/
Cleveland, occupied TN
Steve
Washers last so damned long and are so repairable by the amateur that
the companies were desperate and languishing in a total inability to
grow. The new microprocessor designs were the only way to possibly make
another inroad into profitability by trying to have two tiers of value,
like the difference between a VW and a Lexus!! They intentionally try to
dazzle people with bullshit by pricing uP units waaay higher than a
mechanical, even though uP's are CHEAPER than mechanical timers!! uP's
have proven themselves in shaking environments before, it's nothing like
that. A uP timer would cost about $2 each in quantity running a bank of
opto-TRIAC SSRs for everything. And the displays could be gorgeous!
Shortly this will be unfeasible and they will give up and lapse back
into being a flat business and not trying to score bigtime like a bunch
of thieving yahoos!
-Steve
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Onestone
after having to replace the mechanical timer on my old one 3 times in 5
years. I bought a new Daewoo model, with microprocessors the works, very
simple digital control panel, and cheaper than any mechanical timed
option with other similar features. I also bought a new tumble drier,
believe it or not you do need them here occasionally. After it's rained
for days on end or the temperature drops to 15C and your freezing your
nuts off (tee hee). That too was bought because the old unit, in fact
just 30 months old, and barely out of warranty, had had one heater
element fail, 3 thermostats and one mechanical timer. I replaced it with
the cheapest available model, which happened to be microprocessor
controlled.
They are out there, they are reliable, and only the market will
determine the price. Microprocessors are used a lot in newer machines,
to cut down on development costs. In fact one client asked me to design
a microprocessor front end, but they planned to put a mechanical timer
switch on the front panel of the cheap version, so it 'felt' mechanical,
and a digital panel on the front of the up-market one. In the end they
went purely digital.
Al
Georges
Steve wrote in message <3AC55C...@armory.com>...
Kevin Aylward
"Georges" <geor...@mail.cei.net> wrote in message
news:C1px6.731$Z73.100...@typhoon.cei.net...
GE has a new washer debuting later this year that is microprocesor based
with a 10year parts warranty on it.
Steve wrote in message <3AC55C...@armory.com>...
If they don't warrenty the labour as well, the warranty is worth fuck all.
Bernd Felsche
>Must just be the local market. last year I bought a new washing machine
>after having to replace the mechanical timer on my old one 3 times in 5
>years. I bought a new Daewoo model, with microprocessors the works, very
>simple digital control panel, and cheaper than any mechanical timed
>option with other similar features. I also bought a new tumble drier,
>believe it or not you do need them here occasionally. After it's rained
>for days on end or the temperature drops to 15C and your freezing your
>nuts off (tee hee). That too was bought because the old unit, in fact
>just 30 months old, and barely out of warranty, had had one heater
>element fail, 3 thermostats and one mechanical timer. I replaced it with
>the cheapest available model, which happened to be microprocessor
>controlled.
Hmmm... I'm just thinking that they might be using Pentiums for
eheating elements in the dryer. :-)
>They are out there, they are reliable, and only the market will
>determine the price. Microprocessors are used a lot in newer machines,
>to cut down on development costs. In fact one client asked me to design
>a microprocessor front end, but they planned to put a mechanical timer
>switch on the front panel of the cheap version, so it 'felt' mechanical,
>and a digital panel on the front of the up-market one. In the end they
>went purely digital.
>Al
>The Technical Manager wrote:
>>
>> Back in the mid 1980s high end washing machines used a microprocessor
>> controlled timer and an LED or phosphorescent display instead of the
>> traditional mechanical timer.
>> Why is it that washing machines produced nowadays continue to use
>> mechanical timers when microprocessor timers would be cheaper. Infact
>> virtually no washing machines have microprocessor timers anymore.
>>
>> Is it to do with reliability. Washing machines vibrate hard and harsh
>> vibrations are not good for solder joints, but then mechanincal timers
>> are precision components themselves. Or is it to do with customers not
>> liking a digital interface and prefer to turn a knob instead.
--
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ualski
I'll go along with that. We happen to own a ten year old miele with
microprocessor controls and which has had zero problems, requiring only
regular maintenance. Dryer and dishwasher, same story.
Onestone wrote:
>
> Must just be the local market. <<snip>> u
David Milne
I worked for Email in Adelaide 1989 as a TO in their Simpson Applied
Technology Division where we developed controllers and software for
washing machines, dryers, dishwashers. The fridges only had electro-
mechanical devices in them to control the compressor. A LC display
was designed for a fridge, but it didn't get any further than an initial
mockup model. I don't know what happened after 1990 though.
Microprocessor controllers for the washing machines and dishwashers
were mask programmed Motorola 6805 type with an external serial
EEPROM (94C36 as I remember) to remember commonly used settings
on the washer. The only thing that I remember that really had problems
at the time was the motor controller. This was an epoxy encapsulated
device that controlled the startup, and continuation of the motor. I think
it did reversal as well, although I didn't have much to do with it.
The main washing machine controller had 2mm x 5mm rectangular leds
and a 7 segment display on the front panel to indicate cycle status and
user selection. The dishwasher just had the rectangular leds.
The dryer had a simple micro controller that switched relays on and
off, eg the heater element (which had 2 settings, high and low), and
the motor. It also monitored whether the door was open or closed,
and also counted the mains frequency cycles to obtain some idea
as to the length of time it had been operating. This controller was
only marginally more expensive than the equivalent electromechanical
timer at the time.
These were the models I was working on at the time, however I am
unaware of the characteristics of suceeding models.
There was a bias against the electronically controlled machines,
principally from the servicemen, who replaced the controllers
with a new one, rather than look for anything else that may have
been faulty in the washer/dryer/dishwasher or even the operator.
This bias was eventually transferred to the customer, and
conseqently managment who eventually distrusted the micro
controlled whitegoods. Personally, I think I remember that the
software that was written at the time was not really user-friendly,
and people were still confused by the flashing digital clock on their
vcr, so how learning how to program the washing machine was
I guess, like learning how to program a computer, which to many
people would be very intimidating and confusing. In short, too many
bells and whistles.
The whitegoods that have micros in them were developed as an
up-market version of the electromechanical units.
Fisher Paykel, a direct competitor to Simpson at the time (and
probably still are) had them shortly before Simpson's put them in.
Washing machines, dryers and dishwashers all involve water in some way,
consequently there were problems with humidity and corrosion in some
areas, but these were identified and fixed. The vibration involved
with the rotating machinery that had offset loads was sufficient enough
to trigger the offset load switch, so the user had the opportunity to
manually move the washing around and restart the machine. The micros
were fixed in modular plastic enclosures, which were inserted into the
whitegoods. These were deemed sufficient for the purpose of isolating
the controller from vibration.
Mechanical timers aren't really precision equipment, as I see them.
The contacts are susceptable to wear and corrosion and the reliabilty
factor was well down on the electronic controllers, but the servicemen
didn't see this as they were busy replacing the electronic controllers.
BTW, I have a washer and dryer that both have rotary electromechanical
switches in them.<;-)
.
--
Regards
David Milne
ICQ 37590068