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'[PIC] Do you put a resistor in series with digital'
2011\01\10@120358 by Nathan House

picon face
>From what I've read, it doesn't look like it's mandatory to put a
resistor in series with digital/analog inputs, since all of the I/O
pins have a high input impedance. But is it a good idea to do it
anyway? When an I/O pin is configured as an output it's not high
impedance (right?), so a current limiting resistor could theoretically
save the PIC if, for instance, I happened to connect an output pin in
a high state directly to ground.

I'm just trying to make my projects as idiot-proof as possible :-

2011\01\10@145608 by Oli Glaser

flavicon
face
On 10/01/2011 17:03, Nathan House wrote:
> > From what I've read, it doesn't look like it's mandatory to put a
> resistor in series with digital/analog inputs, since all of the I/O
> pins have a high input impedance. But is it a good idea to do it
> anyway? When an I/O pin is configured as an output it's not high
> impedance (right?), so a current limiting resistor could theoretically
> save the PIC if, for instance, I happened to connect an output pin in
> a high state directly to ground.
>
> I'm just trying to make my projects as idiot-proof as possible :-)

In most cases if you want to be as cautious as possible, I'd say it's not a bad idea to use a low value series resistor, especially if you are making a "general purpose" board where you are bringing lots of IOs out and the likelihood of things getting plugged in the wrong way is higher than a "fixed" design.
If you need plenty of current to drive a transistor to get as much gain as possible, e.g a power bipolar with a current gain of 50 would need 20mA base current to be able to pass 1A, so anything over 250 ohms (for 5V) would be too much. So considering a lot of PICs have a maximum rated current of around 20mA anyway, 250 - 500 ohms seems like a reasonable value. Sure others will have some good input here on what works for them - personally, I tend to just "use as required".
One case where might not want any series resistance (or less than 50 ohms) is where you need a very fast output (i.e the pin needs to be able to charge the trace capacitance + input capacitance of whatever you are driving e.g CMOS input, as quickly as possible) so a large current is needed very briefly. Knowing your RC time constant/signal rise time is a good thing for ensuring signal integrity (maybe also transmission line effects/termination at some point)
Simulation (e.g LTSpice, preferably combined with an understanding of the theory behind the results) is good to experiment with things like this quickly, and no risk of ending up with lots of "ex" PICs..  :-)

2011\01\10@170528 by IVP

face picon face
> I'm just trying to make my projects as idiot-proof as possible :-)

Nathan,

It can take more than just a resistor, particularly for inputs.
Current limiting is fine but you need also to look at voltage
limiting

Diodes (Zener, Schottky, TVS, etc) need to be used in some
environments to soak up charge

For example, a circuit with an electromechanical device, eg
relay, solenoid, or capacitor shorting, can impose a spike
when de-energising that is below Vss-0.6V. This can cause
an input pin in the vicinity to latch up and fry. So it needs at
least a Schottky diode (which has a lower Vf than the PIC's
internal diodes) to conduct that spike. In this case, anode to
Vss, cathode to pin. I learned that after losing several analogue
pins and smoked a couple of PICs big time

That's just one example. Noise and voltages come in many
permutations. I've one board which needs much filtering
because it sits right next to a spark plug, another is close to
a 5W radio transmitter

Mostly circuits don't need general over-protection, mostly,
but there are times when you need to consider a specific
circumstance

eg Google for input pin protection

Jo

2011\01\10@184158 by Oli Glaser

flavicon
face
On 10/01/2011 22:05, IVP wrote:
>> I'm just trying to make my projects as idiot-proof as possible:-)
> Nathan,
>
> It can take more than just a resistor, particularly for inputs.
> Current limiting is fine but you need also to look at voltage
> limiting
>
> Diodes (Zener, Schottky, TVS, etc) need to be used in some
> environments to soak up charge

All good advice from Joe - a more rounded answer, which made me realise there are many perspectives here. Looking at the subject of protection and general "idiot proofing" is quite a large and complex one, and the "best" solution depends on quite a few factors (temperature/power/voltage/current range, environmental factors, etc etc). For (a random) example, thermal design is an art in itself, but how much you "need to know" (versus "nice to know") depends a lot on what you will be designing (A USB peripheral? HV switching power supply? Camera Flash? PID motor/temperature loop? Nuclear plant control system?..)
Anyway, I thought I would mention a few decent books off the top of my head that cover the "basic essentials" quite nicely:
 - The Art of Electronics
I think most would agree every EE should have a copy of this one (old, but still one of the most comprehensive books around - plus a new version is due out very soon I believe)
 - Practical Electronics for Inventors
I think this is a good book to start off with, combines (not too much) theory with many useful analogies/circuits/ideas/examples, this and the writing style making concepts a lot easier to understand.
 - High Speed Digital Design (Johnson & Graham)
Maybe a bit out of place here, but a favourite of mine, more advanced theory/maths wise, but worth mentioning as it is an excellent and pretty unique book.
Plus I would suggest getting a couple of MCU (general and PIC based) specific books, plus a couple of analogue based books (e.g. a decent book on opamps)
Can't think of any particular titles right now, but sure Google would provide plenty of ideas (plus others here are likely to have a few decent ideas)

2011\01\10@220014 by Harold Hallikainen

face
flavicon
face
There can be interesting effects when a PIC analog input is driven beyond
the rails of the chip (or when its internal clamp diodes start to
conduct). We have a system where a PIC32 analog input is measuring a
voltage leaving "the box." Works great in the first 1,000 systems shipped.
At one site, however, the system acts strangely. We replace the box. Same
problem. Can't duplicate the problem back at the shop. So, something
unique about the site? There's a cellular tower across the street.
Apparently RF was being conducted into the box and driving the ADC input
pin on the PIC too high. Ferrite beads did not solve the problem. I added
a 10k resistor between the output terminal and the outside wiring to
reduce the amount of RF getting into the box. That solved the problem.
Back at the shop, I was able to duplicate the problem by forcing the
output above about +4V. On the debugger, I could see a bit of an output
port latch being set. I set a breakpoint on a write to that port. As I ran
the voltage above +4V, the error occurred, but the breakpoint was never
hit. So, I'm thinking there's a sneak path in the chip between that latch
and this ADC input pin. We've added stuff to prevent this from occurring,
but it was quite a problem to troubleshoot over the phone. I finally had
to go to the site.

So, running a PIC pin above or below the rails may not damage the chip
(due to the clamp diodes), but it may also act strangely.


Harold




-- FCC Rules Updated Daily at http://www.hallikainen.com - Advertising
opportunities available

2011\01\11@014908 by IVP

face picon face
part 1 1674 bytes content-type:text/plain; charset="iso-8859-1" (decoded quoted-printable)

> the voltage above +4V, the error occurred, but the breakpoint was
> never hit. So, I'm thinking there's a sneak path in the chip between
> that latch and this ADC input pin

I have a strange problem with the attached circuit. It's the PIC I
mentioned that is close to a spark plug. The s/w injects propane
into a cylinder and then ignites it. Typically 50ms valve time, 50ms
mix time then a spark

What is observed is that GPIO5 (which turns the injector valve on)
sometimes shows no activity at all after one or two spark cycles, so
therefore there is no new gas in the cylinder when the spark happens

What's odd is that the pin won't "come alive" again until the circuit
is powered down for a few seconds. A reset won't do it

The circuit has ferrites, zeners, and Schottkys all over the place
(not shown in this earlier schematic), and I even tried opto-isolating
GPIO5. The only thing that makes some difference is the
orientation of the board wrt the spark plug. A metal case helps a
little but it still happens occassionally

I'm wondering if the noise is so great from the spark plug that it
actually gets into the body (DIP8) of the PIC and charges some
transistor or gate inside which stops the s/w from turning the pin
on. Perhaps the dies of some PICs are vulnerable. I've heard that
smaller dies seem to have problems that were not apparent on
larger scale silicon

When I have time I'd like to revisit the project with another PIC,
perhaps an old one. I feel I've tried all the protection and shielding
I can think of so far

If anyone has a similar experience I'd love to hear about it

Joe

part 2 8827 bytes content-type:image/gif; name="proto4_schematic.gif" (decode)


part 3 181 bytes content-type:text/plain; name="ATT00001.txt"
(decoded base64)

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2011\01\11@040624 by Oli Glaser

flavicon
face
On 11/01/2011 06:48, IVP wrote:
> I have a strange problem with the attached circuit. It's the PIC I
> mentioned that is close to a spark plug. The s/w injects propane
> into a cylinder and then ignites it. Typically 50ms valve time, 50ms
> mix time then a spark
>
> What is observed is that GPIO5 (which turns the injector valve on)
> sometimes shows no activity at all after one or two spark cycles, so
> therefore there is no new gas in the cylinder when the spark happens
>
> What's odd is that the pin won't "come alive" again until the circuit
> is powered down for a few seconds. A reset won't do it
Interesting..
Have you tried swapping from GPIO5 to see whether the problem is unique to that pin?

2011\01\11@050350 by IVP

face picon face
>> What's odd is that the pin won't "come alive" again until the circuit
>> is powered down for a few seconds. A reset won't do it
>
> Interesting..

Not the word I've been using .......

> Have you tried swapping from GPIO5 to see whether the problem
> is unique to that pin?

The client has it at the moment trying a few physical arrangements of
the various parts of the product. He's not having much luck affecting
the reliability so I'm due to get it back soon. As it is such a frustrating
fault there's no love lost between me and the circuit so it'll be hacked
up for sure ;-)

I would like to know if the fault appears on any selected pin, but only
on the way to some sort of re-design, which will involve trying other
PICs to see if they are EMI 'harder' than the 12F675, if indeed that is
what turns out to be the problem

Had me up for two nights at the time with a scope and a selection of
filter components, to no avail. It was just as bad as when I started

As the intention is for a commercial venture, it does have to be sorted
out, so it's not just idle musings

Jo

2011\01\11@054034 by RussellMc

face picon face
> What's odd is that the pin won't "come alive" again until the circuit
> is powered down for a few seconds. A reset won't do it

If you get to play with it again let me have  look - I may have some
useful ideas.

Effect may be:

- SCR latchup. Input circuit is driven into a mode where it self
biases on via parasitic junction. Power off resets SCR.

- Node injection with voltage that drives parasitic or real IC FET
into an on / off state with gate powered by a charge pool that has
nowhere to go. This can take hard power supply short to drain and in
some cases maybe even power down while node drains via whatever sneak
path is available.

I had an IC that if powered off then on again promptly could be
sometimes put into a state where only hard power supply shorting
would restore it. Allowing the supply to trickle down to one Vbe /
diode drop and then to decay very slowly from there, which is commonly
what happens, was not good enough. I implemented a power supply
shorter that clamped the psu rail briefly to ground once it fell below
about 70% of supply. Worked well.

I have seen a video card that took 20 minutes of power off to revive.
(May have been an onboard cap in that case).




           R


{Quote hidden}

>

2011\01\11@061731 by Isaac Marino Bavaresco

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face
part 1 2142 bytes content-type:text/plain; charset="iso-8859-1" (decoded quoted-printable)

By your description, the circuit is probably crying "LATCHUP".

Put some more protection components between the MCU pins and the base of
the transistors.

Attached is the schematic of one of the protection circuits that I use.


Best regards,

Isaac



Em 11/1/2011 04:48, IVP escreveu:
{Quote hidden}


part 2 7763 bytes content-type:image/jpeg; name="Protection.JPG" (decode)


part 3 181 bytes content-type:text/plain; name="ATT00001.txt"
(decoded base64)

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2011\01\11@074451 by Olin Lathrop

face picon face
Nathan House wrote:
> From what I've read, it doesn't look like it's mandatory to put a
> resistor in series with digital/analog inputs, since all of the I/O
> pins have a high input impedance.

Right, sortof.  The inputs are high impedence.  But that means they are more
able to tolerate a resistor in series than if they were low impedence.

There is one additional wrinkle with analog inputs though.  All input pins
have some leakage current.  This leakage current times any series resistance
causes a voltage difference accross that resistance, which is a difference
from the actual analog voltage to what the PIC sees.  For digital inputs,
this only matters if the error got far enough to get out of the guaranteed 1
or 0 region.  Let's say the pin leakage current is guaranteed not to exceed
1uA.  That means a 100K resistor can cause up to 100mV error.  That's
generally not going to be a problem for a digital input since you only want
to know whether the voltage is representing a high or low.  However, when
you are trying to measure the real voltage, 100mV error is a lot.  If the
PIC is running on 5V, then that's one part in 50, or not even 6 bits
effective A/D accuracy.

This is why there is a minimum source impedence spec for driving PIC analog
inputs.  For most older PIC 16 with 10 bit A/D, this is 10K Ohms.  Some
newer and PICs with higher speed and higher resolution A/D have
significantly lower input impedence specs.

> But is it a good idea to do it anyway? When an I/O pin is
> configured as an output it's not high
> impedance (right?), so a current limiting resistor could theoretically
> save the PIC if, for instance, I happened to connect an output pin in
> a high state directly to ground.
>
> I'm just trying to make my projects as idiot-proof as possible :-)

It is easy to go overboard with this.  In environments with high noise and
spikes, like in a car, you have to think about this carefully.  Most of the
time you'll cause more trouble than you solve trying to make things idiot
proof.  Idiots can be very clever.

I would not add any series resistors on the generic board.  Add them as
needed in particular applications.  In reality, PICs and most other digital
logic can tolerate a output tied to the opposite rail without getting
damaged, at least for a few seconds.  Of course you should never rely on
this in a design, but the occasional accidental short of a output pin while
messing with a one off personl project isn't going to be a problem the vast
majority of the time.


********************************************************************
Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products
(978) 742-9014.  Gold level PIC consultants since 2000

2011\01\11@080802 by Olin Lathrop

face picon face
IVP wrote:
> The only thing that makes some difference is the
> orientation of the board wrt the spark plug. A metal case helps a
> little but it still happens occassionally
>
> I'm wondering if the noise is so great from the spark plug that it
> actually gets into the body (DIP8)

Far more likely is that the EMP caused by the spark is causing voltage
offsets acrross the board.  This is a case where careful consideration of
ground layout, ground currents, and other loop currents is very important.
Fortunately the same things you do to design for low emission work to make
the system less susceptible to received radiation.

Show the layout.  That's where the problem will be.


********************************************************************
Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products
(978) 742-9014.  Gold level PIC consultants since 2000

2011\01\11@095159 by RussellMc

face picon face
> I agree Latchup looks like the most likely culprit, but how it's
> happening is what I thought may be a little different.
> I noted Joe said he tried an opto-isolator, which should provide pretty
> good protection on the pin. If a "direct" path, I thought it more likely
> the power supply may be getting corrupted (i.e. if the HV and PIC
> circuits are sharing power+ground)
> If this is the case a DC to DC could be used between the two sections
> (looks like it's all powered by the battery from the circuit posted)

Temporary operation form a local battery can be useful when
troubleshooting this sort of thing.

Location of battery and what is left connected may help in cause localisation.

eg best results probably achieved by a battery connected wt short
leads to processor supply and with usual power circuitry diconnected
near connection to cpu (subject to power continuity leads for other
parts.

Worst case improvement may be to use battery connected to regulator
used to provide cpu . (This allow maximum induction into circuitry,
glitches on rail preregulator etc.

Common sense and careful thinking required.


2011\01\11@103604 by Nathan House

picon face
Thanks for all the info!

>Most of the time you'll cause more trouble than you solve
>trying to make things idiotproof. Idiots can be very clever.

This reminds me of a quote, "A common mistake people make when trying
to design something completely foolproof is to underestimate the
ingenuity of complete fools." - Douglas Adam

2011\01\11@133942 by N. T.

picon face
Olin Lathrop wrote:
> Most of the
> time you'll cause more trouble than you solve trying to make things idiot
> proof.  Idiots can be very clever.
>
> I would not add any series resistors on the generic board.  Add them as
> needed in particular applications.  In reality, PICs and most other digital
> logic can tolerate a output tied to the opposite rail without getting
> damaged, at least for a few seconds.

Yes, digital I/O ports are current-limited.

2011\01\11@143200 by Wouter van Ooijen

face picon face
>> I would not add any series resistors on the generic board.  Add them as
>> needed in particular applications.  In reality, PICs and most other digital
>> logic can tolerate a output tied to the opposite rail without getting
>> damaged, at least for a few seconds.
>
> Yes, digital I/O ports are current-limited.

Not in the sense that there is actual circuitry that limits the current to a specific value, and also not in the sense that you can use this current-limiting in the normal mode of operation of your design. So IMHO your remark is at least misleading.

--
Wouter van Ooijen

-- -------------------------------------------
Van Ooijen Technische Informatica: http://www.voti.nl
consultancy, development, PICmicro products
docent Hogeschool van Utrecht: http://www.voti.nl/hvu

2011\01\11@150717 by N. T.

picon face
Wouter van Ooijen wrote:
>>> I would not add any series resistors on the generic board.  Add them as
>>> needed in particular applications.  In reality, PICs and most other digital
>>> logic can tolerate a output tied to the opposite rail without getting
>>> damaged, at least for a few seconds.
>>
>> Yes, digital I/O ports are current-limited.
>
> Not in the sense that there is actual circuitry that limits the current
> to a specific value, and also not in the sense that you can use this
> current-limiting in the normal mode of operation of your design. So IMHO
> your remark is at least misleading.

I meant my remark in the sense of the post they were in reply to, that
is "In reality, PICs and most other digital
logic can tolerate a output tied to the opposite rail without getting
damaged, at least for a few seconds."

2011\01\11@160058 by Olin Lathrop

face picon face
N. T. wrote:
>> I would not add any series resistors on the generic board. Add them
>> as needed in particular applications. In reality, PICs and most
>> other digital logic can tolerate a output tied to the opposite rail
>> without getting damaged, at least for a few seconds.
>
> Yes, digital I/O ports are current-limited.

Not really, and that's not what I said.  Read the datasheet instead of
making up nonsense.

Regular totem pole digital outputs are implemented with high and low drive
transistors.  These are designed to switch fast.  They are designed to
handle the inevitable capacitive loads that will be on the digital lines
that they drive.  They are also designed for some level of current that they
can handle indefinitely.  However, this is not the same as the current they
can pass if you turn them on and short the output to the opposite rail.
Doing so exceeds specs, and will cause lots of heat in the output
transistor.  Some technologies and implementations will handle that better
than others.  In my experience, PICs handle it quite well, but there is no
guarantee of this in any particular instance.

PIC outputs are implemented as MOSFETs, so will mostly look like a resistor
when turned on.  The output is not current limited, since that implies
something deliberate, and that it will limit to some safe level.  The MOSFET
acting like a resistor only limits the current because it is sortof a
resistor, but there is no guarantee what that current will be or whether it
will be low enough to not cause damage.


********************************************************************
Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products
(978) 742-9014.  Gold level PIC consultants since 2000

2011\01\11@173224 by Richard Prosser

picon face
Joe,
I guess you've tried you tried screening the chip or pcb? i.e. putting
a well earthed metal barrier between the spark & the sensitive
circuitry. It looks to me as if a fast transient is getting into the
chip "somehow" despite  all the diodes and caps you've added.

Adding a separate screen around the spark generating circuitry &
wiring & connecting that to the local earth may also assist.

RP

On 12 January 2011 10:42, IVP <spam_OUTjoecolquittTakeThisOuTspamclear.net.nz> wrote:
{Quote hidden}

>

2011\01\11@204604 by Richard Prosser

picon face
Joe -

It looks like the problems started when you cabled to the spark.
Is the cable going to the spark plug/gap. a resistance type lead or
just copper? Resistance spark plug leads are a pain, but they do work
in reducing RF emissions.

You could also try using coaxial cable to feed the spark (screen
earthed). I did this with one of my cars and it did reduce the noise
significantly. It also reduced the spark to the the point that while I
got where I was going on the first trip, I had to change the leads
beack in order to get home!

RP

On 12 January 2011 13:04, IVP <.....joecolquittKILLspamspam@spam@clear.net.nz> wrote:
{Quote hidden}

>

2011\01\12@004645 by N. T.

picon face
Olin Lathrop wrote:
> N. T. wrote:
>>> I would not add any series resistors on the generic board. Add them
>>> as needed in particular applications. In reality, PICs and most
>>> other digital logic can tolerate a output tied to the opposite rail
>>> without getting damaged, at least for a few seconds.
>>
>> Yes, digital I/O ports are current-limited.
>
> Not really, and that's not what I said.  Read the datasheet instead of
> making up nonsense.

You might have overlooked my reply to Wouter van Ooijen, or, probably,
your email client issue:

===
I meant my remark in the sense of the post they were in reply to, that
is "In reality, PICs and most other digital logic can tolerate a
output tied to the opposite rail without getting damaged, at least for
a few seconds."
===

That was your post I referred  to when replying to Wouter, and I don't
find your post to be "making up nonsense".


> The output is not current limited, since that
> implies something deliberate, and that it will limit
> to some safe level.

Yes it would imply that, if it were not in the context of your post it
was in reply to. In that context it means - Yes, "PICs and most other
digital logic can tolerate a output tied to the opposite rail without
getting damaged, at least for a few seconds", that is, the current
will be getting limited. Of course, this mode is heavily "out of
specs" and must not be recommended.

Regards
:-)

2011\01\12@022402 by Wouter van Ooijen

face picon face
>>> Yes, digital I/O ports are current-limited.
>>
>> Not really, and that's not what I said.  Read the datasheet instead of
>> making up nonsense.
>
> You might have overlooked my reply to Wouter van Ooijen, or, probably,
> your email client issue:
>
> ===
> I meant my remark in the sense of the post they were in reply to, that
> is "In reality, PICs and most other digital logic can tolerate a
> output tied to the opposite rail without getting damaged, at least for
> a few seconds."
> ===

OK, I'll respond. You answered "Yes, digital I/O ports are current-limited." to Olin's explanation. Olin's explanation/statement is factually correct in itself. Yours is definitely not. It does not add anything to Olin's statement, it only adds confusion. "Current-limited" is not a good term in this context (a less moderate qualification might be "totally incorrect" or "dangerously misleading").


--
Wouter van Ooijen

-- -------------------------------------------
Van Ooijen Technische Informatica: http://www.voti.nl
consultancy, development, PICmicro products
docent Hogeschool van Utrecht: http://www.voti.nl/hvu

2011\01\12@055738 by N. T.

picon face
Wouter van Ooijen wrote:
{Quote hidden}

I think I should agree with you. Though my original intent was just to
confirm Olin's point that yes, PICs output would tolerate an output
tied to a rail for at least few seconds without getting damaged, the
phrase I used was not good, and when taken out of context can even be
misleading.
Thanks.

2011\01\12@093232 by Olin Lathrop

face picon face
N. T. wrote:
> You might have overlooked my reply to Wouter van Ooijen, or, probably,
> your email client issue:

No, everything was processed in order.  When you make a dumb statement, you
can expect multiple responses.  In this case both Wouter and I replied to
your original statement.  I saw your reply to Wouter, but of course that was
after my replying to your earlier statement.


********************************************************************
Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products
(978) 742-9014.  Gold level PIC consultants since 2000

2011\01\12@094656 by Olin Lathrop

face picon face
N. T. wrote:
> I meant my remark in the sense of the post they were in reply to, that
> is "In reality, PICs and most other digital logic can tolerate a
> output tied to the opposite rail without getting damaged, at least for
> a few seconds."

Yes, that is my statement that you then responded to saying that PIC are
"current limited".  That is misleading at best, outright wrong at worst,
regardless of whatever context the reader is supposed to assume.

What additional information was your statement of "current limited" supposed
to convey?  All one could take from my statement and your addition is that
the reason PICs can tolerate such a short is because there is a current
limiting mechanism in place, which in turn makes it sound OK.  Neither is
true, as I already elaborated in my first response to your assertion of
current limiting.

General advice:  When you make a public blunder like this, trying to save
face to not look stupid has the opposite effect.  Anyone can make a mistake,
and if you say something like "Oops, sorry for the confusion", it is quickly
forgotten without too much of a mental red mark for too long by your name in
most people's minds.  By protesting, you draw attention to the error,
causing what was perhaps a small oops to become a major public stupidity.
There are now more people likely to think much longer that "N.T. doesn't get
current limiting", than if you'd handled this with less fuss.  If you don't
want to make it even worse, it would be wise to let it go here.


********************************************************************
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2011\01\12@114201 by N. T.

picon face
Wouter van Ooijen <wouterspamKILLspamvoti.nl> wrote:
>> General advice:  When you make a public blunder like this, trying to save
>> face to not look stupid has the opposite effect.  Anyone can make a mistake,
>> and if you say something like "Oops, sorry for the confusion", it is quickly
>> forgotten without too much of a mental red mark for too long by your name in
>> most people's minds.
>
> In the hope of extinguishing a possible flame: to the credit of N.T,
> that is exactly what he did in a subsequent mail:

I said that I agree with you approx 4 hours earlier his post he tells
I should do that :-)
One should be on a special mission inhere to feel good, giving away
such delayed advices :-)


{Quote hidden}

If I said "most people reply in order of arrival", the guy would blame
on me, - "How did I figure 'most'?" :-)
I would suggest that most people are looking through a thread before
replying to it. Gmail helps doing that quite nicely.
Definitely, posting lengthy messages teaching someone to do something
after he had done that already 4 hours before, looks a bit strange.

2011\01\12@115127 by Bob Blick

face
flavicon
face

On Wed, 12 Jan 2011 18:41:56 +0200, "N. T." said:

> I would suggest that most people are looking through a thread before
> replying to it. Gmail helps doing that quite nicely.
> Definitely, posting lengthy messages teaching someone to do something
> after he had done that already 4 hours before, looks a bit strange.

It's like a Monty Python sketch except not so pleasant for the people
directly involved.

Having a tough skin helps. Your behavior was admirable, I would have
stepped in but you handled it well.

Friendly regards, Bob

-- http://www.fastmail.fm - A no graphics, no pop-ups email service

2011\01\12@120147 by Olin Lathrop

face picon face
N. T. wrote:
>> And for N.T: most people (including myself) reply in order of
>> arrival,
>> so a reply will often NOT take subsequent mails in consideration. As
>> often, Olin and I reply with the same opinion, but with some
>> difference
>> of expression :)
>
> If I said "most people reply in order of arrival", the guy would blame
> on me, - "How did I figure 'most'?" :-)
> I would suggest that most people are looking through a thread before
> replying to it.

I think you're wrong, but short of taking a poll (no, let's not do that)
none of us really knows.  However, I did say earlier that I respond to
PIClist posts in order, and Wouter has also said he does too.

> Definitely, posting lengthy messages teaching someone to do something
> after he had done that already 4 hours before, looks a bit strange.

Not if you understand how mail lists work, or at least have been paying
attention to this thread.  I think most people process messages in the order
they are received.  However, whether you think most do that or not, I
already said specifically that I do, so nothing should be strange to you
here.  In any case, what happened here is well within norms anyone should
expect of a email list.


For what it's worth, I generally process posts in order.  If I have been
away from the list for a significant time, I may look forwards before
posting something where a future post could modify what I might say.  My own
threshold for "a significant time" is roughly one day.  So if I've been
checking the list at least daily, then I don't look forwards when responding
to a post.

I think that not taking a future post up to around 24 hours into account is
generally accepted and not out of line for a email list.  I don't know how
others feel, but certainly a few hours is well within the accepted norm,
where a week could be considered rude.


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2011\01\12@121015 by Bob Blick

face
flavicon
face

On Wed, 12 Jan 2011 12:02:46 -0500, "Olin Lathrop" said:


> For what it's worth, I generally process posts in order.

It's been said that those who don't learn from history are doomed to
repeat it :)

Cheerful regards,

Bob

-- http://www.fastmail.fm - IMAP accessible web-mail

2011\01\12@140039 by N. T.

picon face
Olin Lathrop wrote:
> I think that not taking a future post up to around 24 hours into account is
> generally accepted and not out of line for a email list.  I don't know how
> others feel, but certainly a few hours is well within the accepted norm,
> where a week could be considered rude.

That definitely makes sense. I would call it an "academic" approach.
If discussed questions are as serious as it would take a number of
hours to solve the task and compose the reply, and it would take a
number of hours to read and understand the reply, then, yes, it makes
sense to reply the message that had been posted a number of hours ago
without reading newer posts. Though, even in this case it would not
hurt to quickly look through the newer posts. But the probability that
the post would be affected by newer posts is very low, as the
complexity of the academic science is very high.

In the public forums like this one, it's very unlikely that serious
tasks will be solved. A typical reply would take only few minutes.
Thus, in my opinion, in such forums, it makes sense before replying to
the thread, to look through all the unread messages of the thread just
to make sure the problem is not solved already.

But, again, I don't insist on either of the models, both are valid and
let anyone choose the model that fits his nature the best. I'll try
not to call the delays "strange".

2011\01\12@141701 by Olin Lathrop

face picon face
N. T. wrote:
> Thus, in my opinion, in such forums, it makes sense before replying to
> the thread, to look through all the unread messages of the thread just
> to make sure the problem is not solved already.

It may may sense to you, but that's not how I and others do it.  I'm simply
not going to take the trouble to look ahead unless it's really necessary,
like when I've been away more than a day or so.

Having redundant answers or comments within a one day period isn't really
such a bad thing.  Even those that know what they're doing will each have a
slightly different take on things, and certainly will have a different way
of explaining things.  It can be useful to have the same thing explained in
different ways.

Sometimes the number of people on a particular side (with their value taken
into account of course) is a useful indicator of what's more likely to be a
good or bad explaination.  For example, if Russell and I agree then it must
be right ;-)

Another advantage of not looking ahead is not getting stuck in the same
mental rut someone else is.  Sometimes it's harder to think of alternatives
after someone has mentioned a particular solution.  Put another way, it's a
lot easier to think outside the box when you haven't looked inside it.


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(978) 742-9014.  Gold level PIC consultants since 2000

2011\01\13@160915 by N. T.

picon face
Bob Blick wrote:
> On Wed, 12 Jan 2011 12:02:46 -0500, "Olin Lathrop" said:
>
>> For what it's worth, I generally process posts in order.
>
> It's been said that those who don't learn from history are doomed to
> repeat it :)
>

Yeah, that's a real good point, but, maybe, the problem is not how to
learn the lesson, rather the problem would be how to make oneself to
fit the learned model; not that easy task as it might seem to be :-

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