Reliability of basic stamps?
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Posts: 46,084
I'm considering using a basic stamp 2 for an industrial application
where I work. While I am comfortable with both the programming and
implementation, I'm curious about the track record of basic stamps
and how reliable they are. While the odds are slim, a failure of the
basic could cause serious injury or even loss of life. How
comfortable are you users out there with using the basic stamp in
such an application, and if not, what type of microcontroller would
you use?
Thanks!
where I work. While I am comfortable with both the programming and
implementation, I'm curious about the track record of basic stamps
and how reliable they are. While the odds are slim, a failure of the
basic could cause serious injury or even loss of life. How
comfortable are you users out there with using the basic stamp in
such an application, and if not, what type of microcontroller would
you use?
Thanks!
Comments
failure immediately shuts down the equipment. Secondly, your code should
detect invalid sensor conditions, etc... and shut things down when this
occurs.
I would not use any device not designed or intended for this kind of
application, especially where human lives are concerned.
Original Message
> I'm considering using a basic stamp 2 for an industrial application
> where I work. While I am comfortable with both the programming and
> implementation, I'm curious about the track record of basic stamps
> and how reliable they are. While the odds are slim, a failure of the
> basic could cause serious injury or even loss of life. How
> comfortable are you users out there with using the basic stamp in
> such an application, and if not, what type of microcontroller would
> you use?
that the standard device is not intended for life-support applications.
Although it doesn't sound like yours is one such ap, almost any industrial
control application has the potential to contribute to injury if it does not
address all possible failure modes. Any device or system can have such a
failure at any time. The best we can do is to apply all of the directives of
a recognized safety standard, of course being sure that the standard used is
appropriate for the industry and conditions. Many professionals either have
a team member who specializes in safety standards and applications, or they
use a consultant to advise them in the early stages of development and again
to review the finished design.
The Basic Stamps are certainly very reliable controllers if they are used
properly. One can take a chance with a control design for a hazardous
process by doing some research and self educating. If the hazard is
significant, or the company has deep pockets (is large enough to be a good
law suit target) It is best to have a professional safety engineering firm
consult on the design. I have seen many "simple" control designs change
significantly when safety concerns are addressed in a manner that will hold
up under litigation. The less-professional designer thinks that the cost
will be too high, the pro realizes just how high the cost can be if this is
not done.
I often get frustrated when I realize that this scenario often serves to
hold back progress in many industries, but none of us is about to change the
legal systems of the lands in which we live and work, so dealing with it is
a reality.
I am not trying to self-promote shamelessly, but this is what we do here. I
participate on several ANSI & ISO standards committees and I have seen the
results of taking chances. Let me know if I can help.
Chris Loiacono
chris@m...
Autographic
Providing solutions for industry since 1883
>
Original Message
> From: nospam@e... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=a92nKiZ57Y8uejW9Ay7nAyaCkPjj0OzZo_gMs__wm0msrQChOVk61CePckOEfbz36vUQ3Y7_0HX48A]nospam@e...[/url
> Sent: Thursday, September 27, 2001 12:10 PM
> To: basicstamps@yahoogroups.com
> Subject: [noparse][[/noparse]basicstamps] Reliability of basic stamps?
>
>
> I'm considering using a basic stamp 2 for an industrial application
> where I work. While I am comfortable with both the programming and
> implementation, I'm curious about the track record of basic stamps
> and how reliable they are. While the odds are slim, a failure of the
> basic could cause serious injury or even loss of life. How
> comfortable are you users out there with using the basic stamp in
> such an application, and if not, what type of microcontroller would
> you use?
>
> Thanks!
>
>
>
>
> To UNSUBSCRIBE, just send mail to:
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> Subject and Body of the message will be ignored.
>
>
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> http://docs.yahoo.com/info/terms/
>
>
>Firstly, your control circuitry should be designed so that *any* control
>failure immediately shuts down the equipment. Secondly, your code should
>detect invalid sensor conditions, etc... and shut things down when this
>occurs.
I disagree with both statements as they are worded. The control circuitry
should be designed to put the equipment into the safest possible
condition. Shutdown is not always the safest condition. I'm guessing
that's what you really meant, but it isn't what I'm reading.
Jim H
microcontroller and other components would be the last thing you
would want to do, which is why it makes me cautious in approaching it.
--- In basicstamps@y..., Jim Higgins <HigginsJ@s...> wrote:
> At 12:23 09/27/01, Rodent wrote:
>
> >Firstly, your control circuitry should be designed so that *any*
control
> >failure immediately shuts down the equipment. Secondly, your code
should
> >detect invalid sensor conditions, etc... and shut things down when
this
> >occurs.
>
> I disagree with both statements as they are worded. The control
circuitry
> should be designed to put the equipment into the safest possible
> condition. Shutdown is not always the safest condition. I'm
guessing
> that's what you really meant, but it isn't what I'm reading.
>
>
> Jim H
STAMPS's pin input as a confidence check. Does the STAMP have networking? I
can't remember since I don't use them. If so or even if you used serial
data between two stamps you could have each one watching the other. Look at
our space shuttle, like five computers each one watching the other with one
master, if I remember correctly. Another example is our traffic light
system controller, if the MPU fails a safe default condition is assumed
using a hardware backup blinker and relays. It should not be hard to design
a piece of hardware that assumes a safe condition with input from the stamp
to accomplish a task.
Original Message
From: nospam@e... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=927uof5QFv7Gh_zbNjywAROuFkTE1TB2pIkW6ZuFpSNLaYLtJgtAYMLlhAK5yKrweU0FKJbACisaT5D0RwW9]nospam@e...[/url
Sent: Thursday, September 27, 2001 3:41 PM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] Re: Reliability of basic stamps?
Unfortunately, you are correct, in this instance, a shutdown of the
microcontroller and other components would be the last thing you
would want to do, which is why it makes me cautious in approaching it.
--- In basicstamps@y..., Jim Higgins <HigginsJ@s...> wrote:
> At 12:23 09/27/01, Rodent wrote:
>
> >Firstly, your control circuitry should be designed so that *any*
control
> >failure immediately shuts down the equipment. Secondly, your code
should
> >detect invalid sensor conditions, etc... and shut things down when
this
> >occurs.
>
> I disagree with both statements as they are worded. The control
circuitry
> should be designed to put the equipment into the safest possible
> condition. Shutdown is not always the safest condition. I'm
guessing
> that's what you really meant, but it isn't what I'm reading.
>
>
> Jim H
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If I were in that situation, I would not do it. Unless it is your job
to do so.
If it is not part of your job responsibilities, and anyone did get hurt,
you might have a difficult time sleeping at night. And, that could last
you for a lifetime not to mention the impact on the injured and their
families.
I think I heard once that IC's in general have a computed life span of a
few million years in a perfect environment.
What detracts from that is the developer exposing the circuit to
degrading, damaging conditions (heat, moisture, dust, transients,
etc..). You have not supplied sufficient information for anyone to
assist in the analysis of external events impact.
The end result will be that the reliability may not depend so much on
the track record of a specific IC but the skills of the developer.
nospam@e... wrote:
>
> I'm considering using a basic stamp 2 for an industrial application
> where I work. While I am comfortable with both the programming and
> implementation, I'm curious about the track record of basic stamps
> and how reliable they are. While the odds are slim, a failure of the
> basic could cause serious injury or even loss of life. How
> comfortable are you users out there with using the basic stamp in
> such an application, and if not, what type of microcontroller would
> you use?
>
> Thanks!
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and Body
of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
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conflicting sensor readings, any activity that would injure someone should
be stopped immediately -- how you interpret this is your business. This is
totally unrelated to having a stop or panic button on the machine. You would
also need some sort of safety or limit switch so that the machine could not
be restarted until the cutter or whatever is returned to a safe or home
position.
Original Message
> Unfortunately, you are correct, in this instance, a shutdown of the
> microcontroller and other components would be the last thing you
> would want to do, which is why it makes me cautious in approaching it.
>
>
> > >Firstly, your control circuitry should be designed so that *any*
> control
> > >failure immediately shuts down the equipment. Secondly, your code
> should
> > >detect invalid sensor conditions, etc... and shut things down when
> this
> > >occurs.
> >
> > I disagree with both statements as they are worded. The control
> circuitry
> > should be designed to put the equipment into the safest possible
> > condition. Shutdown is not always the safest condition. I'm
> guessing
> > that's what you really meant, but it isn't what I'm reading.
Perhaps to aid the discussion, I could give you a basic idea of how
it would be used (without, of course, giving it all away :-)
Imagine that you were designing a space suit for an astronaut. They
have built in heaters and air conditioners to control the temperature
of the suit. The basic stamp could be used in conjunction with
sensors to maintain the temperature of the suit by monitoring sensors
and turning off and on heaters and air conditioners respectively. If
a failure of the basic stamp were to occur, then you obviously
couldn't just turn it off...because it would either leave a heater
on, an air conditioner on, or leave no environment control at all...
Bad situation.
I understand the implications of needing redundancy, as well as self
monitoring, etc, but my question was more regarding how reliable a
basic stamp is in comparison to other microcontrollers. (All things
being equal, such as operating temperatures, etc). As an engineer,
if you were to open up a space suit life support system and find a
basic stamp controlling it, would you think the designer was crazy?
Thanks for all the input!!
-D
The Basic Stamp family is a mature, reliable, well thought out
implementation of a PIC processor. There are probably more PICs out there
running consumer and industrial embedded applications than any other
processor. Parallax goes to a lot of effort to make their products more
than just toy controllers ( no offense intended to the robot guys ). I have
used everything from embedded 8085's, Z-80s, HC11s and several others. I
stopped "processor hopping" after my first Stamp project. If my project can
work within the speed range, if I don't need interrupts, if i have few I/O
requirements, I'll always look at a Stamp first.
If you design the connecting hardware in an unsafe manner or don't consider
safety issues and failure modes, then it doesn't matter wether you have a
100 hour MTBF or a 200,000 hour MTBF on the processor.
I don't know if I really WOULD send one up in a space suit, but I wouldn't
think twice about having it control a machine in a factory.
Good luck,
Mike
At 10:06 PM 9/27/2001 +0000, you wrote:
>Thanks everyone for the replies.
>
>Perhaps to aid the discussion, I could give you a basic idea of how
>it would be used (without, of course, giving it all away :-)
>
>Imagine that you were designing a space suit for an astronaut. They
>have built in heaters and air conditioners to control the temperature
>of the suit. The basic stamp could be used in conjunction with
>sensors to maintain the temperature of the suit by monitoring sensors
>and turning off and on heaters and air conditioners respectively. If
>a failure of the basic stamp were to occur, then you obviously
>couldn't just turn it off...because it would either leave a heater
>on, an air conditioner on, or leave no environment control at all...
>Bad situation.
>
>I understand the implications of needing redundancy, as well as self
>monitoring, etc, but my question was more regarding how reliable a
>basic stamp is in comparison to other microcontrollers. (All things
>being equal, such as operating temperatures, etc). As an engineer,
>if you were to open up a space suit life support system and find a
>basic stamp controlling it, would you think the designer was crazy?
>
>Thanks for all the input!!
>
>-D
>
>
>To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
>from the same email address that you subscribed. Text in the Subject and
>Body of the message will be ignored.
>
>
>Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
_________________________________
Mike Walsh
walsh@i...
>You could use two, have one say set a pin HIGH and connect that into another
>STAMPS's pin input as a confidence check. Does the STAMP have networking? I
>can't remember since I don't use them. If so or even if you used serial
>data between two stamps you could have each one watching the other. Look at
>our space shuttle, like five computers each one watching the other with one
>master, if I remember correctly. Another example is our traffic light
>system controller, if the MPU fails a safe default condition is assumed
>using a hardware backup blinker and relays. It should not be hard to design
>a piece of hardware that assumes a safe condition with input from the stamp
>to accomplish a task.
By the TIME you do all this, *and* develop reliable code to run it, *and*
design and implement any necessary interface circuitry to interface our
relatively delicate Stamps to the nasty world of industrial machinery and
industrial plant electrical systems, *and* package the whole thing in a box
designed to keep out dust and whatever, *and* factor in the support you
will need to provide in the future for this unique design, you can probably
buy an inexpensive PLC that can be programmed in a much more
straightforward way and with solutions to all the interface issues designed
right into it.
Just my opinion on "force fit" custom solutions.
Jim H
Rodent was correct on the first part. Have you ever used a plc,
which should be this persons first choice for Industrial control.
A plc will drop out of run mode and go into fault mode for a variety
of reasons. Watchdog timeout, bad program, lost program, not
functioning correctly to name a few. When It faults it will drop all
outputs and program will quit functioning. If you don't believe me
look at allen bradley, omeron, mitsubishi, pilz, ge, plc direct,
seimens, just to name a few.
Detection of invalid sensor condition is all part of programming.
This person should be looking at a plc which is designed for
industrial machines. You can get a cheap one for $100 with 8 inputs
and 6 outputs. Plus they use a universal ladder program that looks
simular to relay logic. Also they are used on almost all machine
projects in industrial apps.
Shutdown is not always the safest condition. While this is true osha
mandates yes mandates that all power being air, mechanical,
electrical, or other means will be turned off under any Emergency
stoping conditions so that no movement will come forth. This is why
you use nc contacts on a stop button, spring return valves for air
functions and hydrolics. I don't think that you really want to argue
with OSHA now do you.
Timothy Hosey
Industrial Journeyman Electrician
Certified by the State of Ohio under the Department of Labor
--- In basicstamps@y..., Jim Higgins <HigginsJ@s...> wrote:
> At 12:23 09/27/01, Rodent wrote:
>
> >Firstly, your control circuitry should be designed so that *any*
control
> >failure immediately shuts down the equipment. Secondly, your code
should
> >detect invalid sensor conditions, etc... and shut things down when
this
> >occurs.
>
> I disagree with both statements as they are worded. The control
circuitry
> should be designed to put the equipment into the safest possible
> condition. Shutdown is not always the safest condition. I'm
guessing
> that's what you really meant, but it isn't what I'm reading.
>
>
> Jim H
them does not make them any safer to used. More parts and big software
packages spell big trouble in my book. The BASIC Stamp is a very simple
controller having a small number of parts and very efficient software. Never
in the history of electronics has such a small package been so efficient.
Engineering designers often look at the BASIC Stamp as not being complicated
enough to be real. It is real in every sense and its works well and reliable
in control systems. Some have referred to the BASIC Stamp as the "electronic
Swiss Army knife".
Chuck
[noparse][[/noparse]Non-text portions of this message have been removed]
However, critical process control should be evaluated, not from a
processor standpoint, but from a failure mode standpoint.
Build your system (in a controlled environment)and then hit the reset
button and hold it. See what happens. Regardless of what processor
you use, the question to be asked is what happens if the processor
goes into a catastrophic failure. Do all of the outputs go to a high
state or low state or high impedance and what are the ramifications?
The Company that I work for (full time) is a contract house which
designs, engineers, and produces non-invasive medical equipment,
among other thigs, that can conceivably have the same type of modes
you are discussing.
We use a lot of 8051's for the major stuff and PIC's at times when we
need cheap and dirty. Don't get me wrong, both of these processors
are great. Misapplication can be very costly in many forms. Bean
counters (accountants) generally are just concern themselves with the
immediate bottom line. That's why they tend to cut the engineering
staffs first. and when the company is looking profitable they get a
bonus and bail leaving the company to bleed in the long run. enough
of my rambling.... I would recommend that you evaluate many
processors and study your process and design for a 'failsafe' mode
and then decide on the processor from there
FWIW
Cory --- In basicstamps@y..., nospam@e... wrote:
> I'm considering using a basic stamp 2 for an industrial application
> where I work. While I am comfortable with both the programming and
> implementation, I'm curious about the track record of basic stamps
> and how reliable they are. While the odds are slim, a failure of
the
> basic could cause serious injury or even loss of life. How
> comfortable are you users out there with using the basic stamp in
> such an application, and if not, what type of microcontroller would
> you use?
>
> Thanks!
However, there are times a PLC is not economically feasible.
I being a EE come from a long line of electricians father uncle
cousins etc.
I was in an interview one time at Rockwell (Allen Bradley)
In the interview I was asked why Allen Bradley? I said that I had
made a career out of designing the AB product out of customers
equipment. It is too expensive. They asked me why then Allen
Bradley? I said I have worked around the lead dog, but the view
never changes. He understood. They were laying off 100'S Why the
interview ??? Go figure.
I haven't checked in a while, but can a PLC have 24 I/O, 8 RTD input
channels, 8 pressure/voltage input channels and a 5amp current
channel for under $400?
We build a reliable one
BTW I served my internship as a panel wiring and PLC Technician.
[noparse]:)[/noparse]
--- In basicstamps@y..., thosey@w... wrote:
> B**l S***, Where do you live, Not on Earth as much as I gather.
> Rodent was correct on the first part. Have you ever used a plc,
> which should be this persons first choice for Industrial control.
> A plc will drop out of run mode and go into fault mode for a
variety
> of reasons. Watchdog timeout, bad program, lost program, not
> functioning correctly to name a few. When It faults it will drop
all
> outputs and program will quit functioning. If you don't believe me
> look at allen bradley, omeron, mitsubishi, pilz, ge, plc direct,
> seimens, just to name a few.
> Detection of invalid sensor condition is all part of programming.
>
> This person should be looking at a plc which is designed for
> industrial machines. You can get a cheap one for $100 with 8
inputs
> and 6 outputs. Plus they use a universal ladder program that looks
> simular to relay logic. Also they are used on almost all machine
> projects in industrial apps.
>
> Shutdown is not always the safest condition. While this is true
osha
> mandates yes mandates that all power being air, mechanical,
> electrical, or other means will be turned off under any Emergency
> stoping conditions so that no movement will come forth. This is why
> you use nc contacts on a stop button, spring return valves for air
> functions and hydrolics. I don't think that you really want to
argue
> with OSHA now do you.
>
> Timothy Hosey
> Industrial Journeyman Electrician
> Certified by the State of Ohio under the Department of Labor
>
> --- In basicstamps@y..., Jim Higgins <HigginsJ@s...> wrote:
> > At 12:23 09/27/01, Rodent wrote:
> >
> > >Firstly, your control circuitry should be designed so that *any*
> control
> > >failure immediately shuts down the equipment. Secondly, your
code
> should
> > >detect invalid sensor conditions, etc... and shut things down
when
> this
> > >occurs.
> >
> > I disagree with both statements as they are worded. The control
> circuitry
> > should be designed to put the equipment into the safest possible
> > condition. Shutdown is not always the safest condition. I'm
> guessing
> > that's what you really meant, but it isn't what I'm reading.
> >
> >
> > Jim H
>As an engineer,
>if you were to open up a space suit life support system and find a
>basic stamp controlling it, would you think the designer was crazy?
In this extreme example, I would think he was absolutely certifiable - not
because the Stamp is an incapable device for control purposes, but because
it (probably) isn't hardened to the conditions it will encounter in
space. It's a matter of the right tool for the job. A screwdriver works
as a pry bar, but doing so is asking for trouble over the long haul.
As a cycle controller on a process oven, for another example, no inherent
unsafe mechanical conditions, burner/pilot operation controlled by a
separate dedicated flame safety control, I think it's a fine fit. Suitably
protected from electrical surges, other environmental conditions, etc., I'd
say it's limitations, in general, are the limitations of the programmer -
and of course the physical I/O of the chosen Stamp.
Jim H
>What I was saying is that if the controller takes a dump or you have
>conflicting sensor readings, any activity that would injure someone should
>be stopped immediately -- how you interpret this is your business. This is
>totally unrelated to having a stop or panic button on the machine. You would
>also need some sort of safety or limit switch so that the machine could not
>be restarted until the cutter or whatever is returned to a safe or home
>position.
And if a 300° F mold has closed on the machine operator's hand, do you want
to stop the machine and refuse to restart and return that mold to a safe
open position until it has been pried open by brute force and returned to
its home condition so the machine can be restarted?
Been there, done that, I was the Engineer who bypassed the PLC to free the
poor bastard. I NEVER want to see that again. The company providing the
control system was sued - and lost - big time!
If you write a specification using the words "stopped immediately -- how
you interpret this is your business," you'll be named in any resulting
lawsuit. Worse yet, you'll have to live with what that control system
might do to someone.
Machine shutdown is not always a singular process involving stopping
immediately, or stopping those processes that might injure someone. It
involves stopping those processes in a manner that doesn't increase the
risk of injury and that leaves them in a safe condition. You can stop
closing a mold, but what good is that if a hand is already crushed in
it? You need to open the mold, then stop, as just one example.
This is my last word on this - I promise.
Jim H
>Cory --- In basicstamps@y..., nospam@e... wrote:
> > I'm considering using a basic stamp 2 for an industrial application
> > where I work. While I am comfortable with both the programming and
> > implementation, I'm curious about the track record of basic stamps
> > and how reliable they are. While the odds are slim, a failure of
> > the basic could cause serious injury or even loss of life. How
> > comfortable are you users out there with using the basic stamp in
> > such an application, and if not, what type of microcontroller would
> > you use?
> >
> > Thanks!
HI,
I've used stamps in assorted "controller" projects. A hoist controller,
a vacuum controller, a process controller, a step motor controller, etc.
It ease of use is it's major attraction for me. In all these instances
there has never been a failure of the stamp, nor a risk of injury even
if it did fail.
I have also designed laser interlock systems, furnace safety systems,
etc, where personal injury is a possibility. I haven't yet used a stamp
where these risks are present. If death were a possibility I wouldn't
even consider a stamp.
Let me restate that in every application where I've used a stamp it
has NEVER failed. Surely one might think the safety record allows
it's use in more hazardous situations. The reason I won't use it
is it's not an off the shelf solution. It's custom. It's serviceability
me be restricted to me or a few knowledgeable people familiar
with its use and program. Most importantly it's not my job to design
a finished product, put it through the required testing and QA in
order to sell it to the public and put my company name on the
bottom line of a liability suit. Where the real concern of human
life and injury are at stake, do you want to be responsible?
I'm not saying the stamp couldn't be used or shouldn't be used. I
am saying that if used where life is at risk, it must be thoroughly
tested and developed as an off the shelf solution with all of the
OSHA, UL, and other certifications that apply. Life is a serious
issue.
Greg Hensley
Lawrence Livermore National Laboratory
Defense Sciences Engineering Division
7000 East Avenue Mail Stop L-369
Livermore, CA 94550
Phone: (925) 423-4850
Fax: (925) 422-2118
Email: hensley1@l...
environments on low power. The Stamp has proven to be very reliable.
The specific Stamp hardware issues that have been most problematic
for me have been its behavior in Sleep mode, and its behavior in
brownout. Saving data and saving the batteries are primary system
reliability concerns.
BASIC Stamp operation is deterministic (no interrupts) and highly
reliable from that standpoint. It's KISSness is a big asset, but
trouble comes from stretching it to do too much. It is easy to make a
quick program on the Stamp, but it takes more discipline to make a
structured program.
2 cents--Every processor (Stamp/PIC, HC11, 8051 etc) has quirks.
There is nothing like experience to learn what those quirks are and
to anticipate their consequences. It is like becoming fluent in a
language. The same goes for all of the parts that go to make up a
system. Some parts are more problematic than others, say, op amps and
connectors are more problematic than resistors. So reliability
depends on experience both with the system to be instrumented and
with the tools used. Then there is the bigger picture--who else is
going to have to service it down the road, who evaluates it, uses it,
insures it etc etc.
regards,
-- Tracy
I am an industrial engineer and I use the stamp every
where including machines that pose a possible human
risk. One such app. is a die cutting device that feeds
paper in with a stepper drive system that is all
controlled by a stamp. The reliablity of the stamp is
rock stable. The safety issue brings up other design
factors that should be out of the processors control.
In a failed condition, all processors can fail, the
design of the machine should be such that interlocks,
stop switches, pressure switches, overrun sensors and
more should isolate the operator from the possibility
of injury. I have been installing stamps in industrial
apps. for over two years. These devices run up to 16
hours per day. To my knowledge, I have never had a
failure.
Scott Sutton
--- Greg Hensley <hensley1@l...> wrote:
>
> >
> >Cory --- In basicstamps@y..., nospam@e...
> wrote:
> > > I'm considering using a basic stamp 2 for an
> industrial application
> > > where I work. While I am comfortable with both
> the programming and
> > > implementation, I'm curious about the track
> record of basic stamps
> > > and how reliable they are. While the odds are
> slim, a failure of
> > > the basic could cause serious injury or even
> loss of life. How
> > > comfortable are you users out there with using
> the basic stamp in
> > > such an application, and if not, what type of
> microcontroller would
> > > you use?
> > >
> > > Thanks!
>
> HI,
>
> I've used stamps in assorted "controller" projects.
> A hoist controller,
> a vacuum controller, a process controller, a step
> motor controller, etc.
> It ease of use is it's major attraction for me. In
> all these instances
> there has never been a failure of the stamp, nor a
> risk of injury even
> if it did fail.
>
> I have also designed laser interlock systems,
> furnace safety systems,
> etc, where personal injury is a possibility. I
> haven't yet used a stamp
> where these risks are present. If death were a
> possibility I wouldn't
> even consider a stamp.
>
> Let me restate that in every application where I've
> used a stamp it
> has NEVER failed. Surely one might think the safety
> record allows
> it's use in more hazardous situations. The reason I
> won't use it
> is it's not an off the shelf solution. It's custom.
> It's serviceability
> me be restricted to me or a few knowledgeable people
> familiar
> with its use and program. Most importantly it's not
> my job to design
> a finished product, put it through the required
> testing and QA in
> order to sell it to the public and put my company
> name on the
> bottom line of a liability suit. Where the real
> concern of human
> life and injury are at stake, do you want to be
> responsible?
>
> I'm not saying the stamp couldn't be used or
> shouldn't be used. I
> am saying that if used where life is at risk, it
> must be thoroughly
> tested and developed as an off the shelf solution
> with all of the
> OSHA, UL, and other certifications that apply. Life
> is a serious
> issue.
>
> Greg Hensley
> Lawrence Livermore National Laboratory
> Defense Sciences Engineering Division
> 7000 East Avenue Mail Stop L-369
> Livermore, CA 94550
> Phone: (925) 423-4850
> Fax: (925) 422-2118
> Email: hensley1@l...
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed.
> Text in the Subject and Body of the message will be
> ignored.
>
>
> Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
>
>
__________________________________________________
Do You Yahoo!?
Listen to your Yahoo! Mail messages from any phone.
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From an ethical standpoint the question is simple. Don't
deploy anything you would not want your own loved ones to work
with. Whatever is required for that comfort level, that is what
you must do.
I don't know about you, but I personally know people who have
made bad decisions that they know have cost other people their
lives, and it is not a place you *ever* want to be, believe me.
Ken Ambrose
with enough thrust, pigs fly just fine.
---- On Thu, 27 Sep 2001, nospam@e...
(nospam@e...) wrote:
> I'm considering using a basic stamp 2 for an industrial
application
> where I work. While I am comfortable with both the
programming and
> implementation, I'm curious about the track record of basic
stamps
> and how reliable they are. While the odds are slim, a
failure of the
> basic could cause serious injury or even loss of life. How
> comfortable are you users out there with using the basic
stamp in
> such an application, and if not, what type of microcontroller
would
> you use?
>
> Thanks!
>
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the
Subject
> and Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
>
>
>
>
experience that there are many Stamps in commercial
and industerial environments. In our experience we have not seen the stamps
misbehave or have any errent behaviour. Ususally the
strength of the code will determine the reliability. I would recomend that no
matter what processor you use you should always
implement safety controls and counter measures. No computer / software will be
perfect. It is always necessary to have backups in
place if the risk of failure is life threatening...
my $0.02.
MH
Original Message
From: "Ken Ambrose" <kenzo@u...>
To: "nospam@e..." <basicstamps@yahoogroups.com>
Sent: Friday, September 28, 2001 11:41 PM
Subject: Re: [noparse][[/noparse]basicstamps] Reliability of basic stamps?
> Hi,
>
> From an ethical standpoint the question is simple. Don't
> deploy anything you would not want your own loved ones to work
> with. Whatever is required for that comfort level, that is what
> you must do.
>
> I don't know about you, but I personally know people who have
> made bad decisions that they know have cost other people their
> lives, and it is not a place you *ever* want to be, believe me.
>
>
> Ken Ambrose
>
>
> with enough thrust, pigs fly just fine.
>
>
>
> ---- On Thu, 27 Sep 2001, nospam@e...
> (nospam@e...) wrote:
>
> > I'm considering using a basic stamp 2 for an industrial
> application
> > where I work. While I am comfortable with both the
> programming and
> > implementation, I'm curious about the track record of basic
> stamps
> > and how reliable they are. While the odds are slim, a
> failure of the
> > basic could cause serious injury or even loss of life. How
> > comfortable are you users out there with using the basic
> stamp in
> > such an application, and if not, what type of microcontroller
> would
> > you use?
> >
> > Thanks!
> >
> >
> >
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> > from the same email address that you subscribed. Text in the
> Subject
> > and Body of the message will be ignored.
> >
> >
> > Your use of Yahoo! Groups is subject to
> > http://docs.yahoo.com/info/terms/
> >
> >
> >
> >
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and Body
of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
Original Message
> From: Chris Loiacono [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=L2m6JH2lglgGQiPwzZbasL7Iz_jXib9hJOm7IlWcYdwAyx4cXJP4J91fLPxLjOQrMTF8D7ujhBYSlvKGLQ]chris@m...[/url
> Sent: Saturday, September 29, 2001 2:38 PM
> To: 'basicstamps@yahoogroups.com'
> Subject: RE: [noparse][[/noparse]basicstamps] Re: Reliability of basic stamps?
>
>
> I'm with the Doc on this one. Some PLC's are good for certain
> applications. I have used a number of them, and in general
> find them to be slow, costly and buggy. Ladder logic is less
> flexible than I would prefer, plus, I have helped fix bugs on
> major manufacturer's PLC's as well. It seems that you will
> find bugs on any of them if you work them in numerous applications.
>
> Do the same job with a microcontroller chip and your own
> dedicated input circuits and you have what should be a more
> reliable, simpler version of a PLC without all the unused
> overhead in cost, code and performance.
>
> Deterministic operation is even simpler and s/b even more
> reliable, plus many of you guys have enlightened me on the
> amazing flexibility that can be innovated in your basic code
> writing. So Stamps are good choices for some applications also.
>
> I use PLC's at times because other factors beside the obvious
> technical ones call for pre-engineered systems. It is
> sometimes easier and faster to comply with safety standards
> because the manufacturers keep themselves up to date on
> standards drafts and updates, which they translate into their
> firmware and hardware upgrades regularly. Also, many off-the
> shelf input devices are ready made for PLC's that have been
> specifically designed to help you comply with safety
> standards. Some customers expect you to purchase a high
> dollar box for their project and don't understand the
> benefits of embedding intelligence at a lower level. Some
> only have support skills in their organizations to work with
> PLC's because that's all they know. Some want you to create
> an original controller for the that's smaller and faster....etc...
>
> Stamps, if not overambitiously applied can be super reliable,
> so can PIC's, or Atmel chips for that matter. The difference
> that counts is the system designer's knowledge of the
> application and the HW & SW he/she uses. As a foundation,
> find the appropriate recognized safety standard for the
> application and be sure to be in 100% compliance with your result.
>
> ANSI has been empowered by the US Congress to write standards
> here, and many are being merged with UL standards. UL
> standards were originally written as tools for insurance
> underwriters. As ANSI standards they are law. In writing ISO
> standards, we are seeking to harmonize these standards
> internationally. In drafting these standards, we use language
> such as "acceptable risk" and "risk management" when
> specifying what type of equipment function or motion requires
> what level of redundancy and protection for personnel and
> property. This more than implies the legalistic reasons for
> applying the standards. One colleague who specializes in
> providing expert testimony does nothing but fly from court
> case to court case in order to demonstrate whether or not the
> designers in each case fully applied the appropriate safety
> standard(s).
>
> So, although the responses have been entertaining, the bottom
> line is like the old cliche: "If you have to ask the price,
> you can't afford it" altered to say: "If you need to ask if a
> specific device is reliable enough to be acceptably safe, you
> aren't ready to do the job yet."
>
> Please, do the homework, pay the dollars for the copies of
> the applicable standards, study and apply them, or
> collaborate with a safety expert to be sure you comply with
> society's accepted standards for safety. It rarely if ever
> has much to do with the choice of technology. It requires
> much more effort than that needed to learn a programming
> language, but the difference is that less people will get
> injured, and less designers and manufacturers will be dragged
> into ugly lawsuits.
>
> Every major manufacturer that produces a device with a plug
> on the end of a wire does it this way. There are reasons it
> costs as much as it does to develop a safe reliable product,
> and there are reasons that we call the successful
> manufacturers "major manufacturers".
>
> OK, that having been said (which I agree is too much), I'll
> be quiet for a while....
>
> Chris
>
> Given the time and ability, there is no
>
> >
Original Message
> > From: Scott Sutton [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=tmwx73zgoLbf5VIv4M3caUoOwzdgd6SUACrLAMPjiHNMdTCk3pK4JGiyMF4cLakeQ7g10GX_E_rUezBPbpJDE1uy]scottsutton67@y...[/url
> > Sent: Friday, September 28, 2001 3:20 PM
> > To: basicstamps@yahoogroups.com
> > Subject: Re: [noparse][[/noparse]basicstamps] Re: Reliability of basic stamps?
> >
> >
> > Cory,
> > I am an industrial engineer and I use the stamp every
> > where including machines that pose a possible human
> > risk. One such app. is a die cutting device that feeds
> > paper in with a stepper drive system that is all
> > controlled by a stamp. The reliablity of the stamp is
> > rock stable. The safety issue brings up other design
> > factors that should be out of the processors control.
> > In a failed condition, all processors can fail, the
> > design of the machine should be such that interlocks,
> > stop switches, pressure switches, overrun sensors and
> > more should isolate the operator from the possibility
> > of injury. I have been installing stamps in industrial
> > apps. for over two years. These devices run up to 16
> > hours per day. To my knowledge, I have never had a
> > failure.
> > Scott Sutton
> > --- Greg Hensley <hensley1@l...> wrote:
> > >
> > > >
> > > >Cory --- In basicstamps@y..., nospam@e...
> > > wrote:
> > > > > I'm considering using a basic stamp 2 for an
> > > industrial application
> > > > > where I work. While I am comfortable with both
> > > the programming and
> > > > > implementation, I'm curious about the track
> > > record of basic stamps
> > > > > and how reliable they are. While the odds are
> > > slim, a failure of
> > > > > the basic could cause serious injury or even
> > > loss of life. How
> > > > > comfortable are you users out there with using
> > > the basic stamp in
> > > > > such an application, and if not, what type of
> > > microcontroller would
> > > > > you use?
> > > > >
> > > > > Thanks!
> > >
> > > HI,
> > >
> > > I've used stamps in assorted "controller" projects.
> > > A hoist controller,
> > > a vacuum controller, a process controller, a step
> > > motor controller, etc.
> > > It ease of use is it's major attraction for me. In
> > > all these instances
> > > there has never been a failure of the stamp, nor a
> > > risk of injury even
> > > if it did fail.
> > >
> > > I have also designed laser interlock systems,
> > > furnace safety systems,
> > > etc, where personal injury is a possibility. I
> > > haven't yet used a stamp
> > > where these risks are present. If death were a
> > > possibility I wouldn't
> > > even consider a stamp.
> > >
> > > Let me restate that in every application where I've
> > > used a stamp it
> > > has NEVER failed. Surely one might think the safety
> > > record allows
> > > it's use in more hazardous situations. The reason I
> > > won't use it
> > > is it's not an off the shelf solution. It's custom.
> > > It's serviceability
> > > me be restricted to me or a few knowledgeable people
> > > familiar
> > > with its use and program. Most importantly it's not
> > > my job to design
> > > a finished product, put it through the required
> > > testing and QA in
> > > order to sell it to the public and put my company
> > > name on the
> > > bottom line of a liability suit. Where the real
> > > concern of human
> > > life and injury are at stake, do you want to be
> > > responsible?
> > >
> > > I'm not saying the stamp couldn't be used or
> > > shouldn't be used. I
> > > am saying that if used where life is at risk, it
> > > must be thoroughly
> > > tested and developed as an off the shelf solution
> > > with all of the
> > > OSHA, UL, and other certifications that apply. Life
> > > is a serious
> > > issue.
> > >
> > > Greg Hensley
> > > Lawrence Livermore National Laboratory
> > > Defense Sciences Engineering Division
> > > 7000 East Avenue Mail Stop L-369
> > > Livermore, CA 94550
> > > Phone: (925) 423-4850
> > > Fax: (925) 422-2118
> > > Email: hensley1@l...
> > >
> > >
> > > To UNSUBSCRIBE, just send mail to:
> > > basicstamps-unsubscribe@yahoogroups.com
> > > from the same email address that you subscribed.
> > > Text in the Subject and Body of the message will be
> > > ignored.
> > >
> > >
> > > Your use of Yahoo! Groups is subject to
> > > http://docs.yahoo.com/info/terms/
> > >
> > >
> >
> >
> > __________________________________________________
> > Do You Yahoo!?
> > Listen to your Yahoo! Mail messages from any phone.
> > http://phone.yahoo.com
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> > from the same email address that you subscribed. Text in the
> > Subject and Body of the message will be ignored.
> >
> >
> > Your use of Yahoo! Groups is subject to
> > http://docs.yahoo.com/info/terms/
> >
> >
>
would he be "certifiable". Assuming the stamp was in an
environmentally controled environment, and barring any meteors, why
wouldn't it be suited?
I used this example to try and demonstrate an instance in which the
programming is fairly simple (too cold, turn on heater, too hot turn
on AC), but upon which life clearly depends. It sounds to me that the
stamp is no more suited, but no less than other devices.
-D
> In this extreme example, I would think he was absolutely
certifiable - not
> because the Stamp is an incapable device for control purposes, but
because
> it (probably) isn't hardened to the conditions it will encounter in
> space. It's a matter of the right tool for the job. A screwdriver
works
> as a pry bar, but doing so is asking for trouble over the long haul.
>
> As a cycle controller on a process oven, for another example, no
inherent
> unsafe mechanical conditions, burner/pilot operation controlled by
a
> separate dedicated flame safety control, I think it's a fine fit.
Suitably
> protected from electrical surges, other environmental conditions,
etc., I'd
> say it's limitations, in general, are the limitations of the
programmer -
> and of course the physical I/O of the chosen Stamp.
>
>
> Jim H
university experiments package and we (Parallax) routinely get orders from
NASA and other government agencies. They'll never tell us what they're doing
with them though....
-- Jon Williams
-- Applications Engineer, Parallax
In a message dated 10/10/01 6:42:31 PM Central Daylight Time,
nospam@e... writes:
> Given, that this is an extreme example, but why, in your opinion,
> would he be "certifiable". Assuming the stamp was in an
> environmentally controled environment, and barring any meteors, why
> wouldn't it be suited?
>
> I used this example to try and demonstrate an instance in which the
> programming is fairly simple (too cold, turn on heater, too hot turn
> on AC), but upon which life clearly depends. It sounds to me that the
> stamp is no more suited, but no less than other devices.
>
> -D
>
> > In this extreme example, I would think he was absolutely
> certifiable - not
> > because the Stamp is an incapable device for control purposes, but
> because
> > it (probably) isn't hardened to the conditions it will encounter in
> > space. It's a matter of the right tool for the job. A screwdriver
> works
> > as a pry bar, but doing so is asking for trouble over the long haul.
> >
> > As a cycle controller on a process oven, for another example, no
> inherent
> > unsafe mechanical conditions, burner/pilot operation controlled by
> a
> > separate dedicated flame safety control, I think it's a fine fit.
> Suitably
> > protected from electrical surges, other environmental conditions,
> etc., I'd
> > say it's limitations, in general, are the limitations of the
> programmer -
> > and of course the physical I/O of the chosen Stamp.
> >
> >
> >
[noparse][[/noparse]Non-text portions of this message have been removed]
I took two different stamp controlled devices (camera control electronics
and single frame stepper motor) far far too close to the North Pole for my
health [noparse]:)[/noparse] I was very very worried at how they would stand up. We had
problems .. but not with the stamps. Batteries were a big problem our
unbelievably expensive Lithium Ion's were a nightmare and we should have had
EVEN thinner oil in the camera than we did. The stamps were faultless.
And yet it was them I was worried about, there is something very scary about
taking something you personally put together into a hostile environment,
because responsibility for failure is totally yours (or in this case mine).
Justin
Well as of now ,,, at work I 5 STAMP's on the " shop floor " .
Some about two to three years old . In fact one application " receives "
it's 110 ac from the auxiliary outlet on a welding transformer . As of today
none of the STAMP's have failed . But who knows what tomorrow will bring .
[noparse][[/noparse]Non-text portions of this message have been removed]