As it said.
   We need to replace some analog PID boards due to supply and
side effects the existing ones have.

   The PID code that comes in digital drives and process controllers
are pretty much what we're looking for how ever, we only need just
a design that allows a input ref, reference feed back and a output
to drive what ever device.
  This device should have it's own mini LCD interface to set the
values or at least a computer hook up to do so.

   It should have the standard Proportional Gain, Integral and
derivative components to set the values.

   Also, having an option to select unipolar and bipolar output
is a plus!..

  I know there are various analog boards out there already that
do this how ever, We have found that they seem to exhibit side
effects and cause self oscillation under some conditions.

  In the digital varieties, I have found this not to be a problem
because it's being done via software and thus these effects are not visible.

  I have already made a few using a AVR/ATMega that employ the ADC 
inputs and we simply buffer the output into a PWM filter and op-amp.
   These units are programmed via a serial connection for the params.

  How ever, my employer wants to buy units that are ready made so that
replacements can be had with out depending on in-house designs.

   I have looked and I can't find a unit that has a build on LCD display
with a simple interface to do this..

  We do have a SSD out board key pad unit that does do this function for 
us along with some other little nifty things how ever, it appears that 
this unit is no longer available.

  Any idea's?

On Wed, 01 Jul 2009 14:14:47 -0400, Jamie
<j...@charter.net> wrote:

><snip about PID>
>  Any idea's?

No ideas.  Some comments.

I'm not clear about exactly how you are using these PID units, right
now.  It almost sounds as though you are an off-the-shelf consumer of
PID controllers with a specific process to control -- except for the
fact that you talk about unipolar and bipolar operation being a plus,
which suggests that you have a variety of situations to deal with and
not just the one.  That makes me imagine you more in the position of
not really knowing where the PID is being applied and that you want a
more general solution as an OEM supplier to end users (which implies
you aren't the end user of the PID.)  Are you and end-user or do you
supply something to others that must include PID as a feature?

You also mention self-oscillation, which is a fairly common problem
I've seen with PID -- especially where there is a significant time
delay in the loop.  One of the cheaper ways to handle that is to
simply shorten the delay.  Even a brain-dead PID controller can do a
credible job on controlling a process where the loop time is shorter
and repeatable.

You mention having created a solution with an ATmega that works
already, but that your company doesn't want to use it.  Instead
preferring to buy something on the outside.  Why?  Many would very
much like to be in control of something like this.  You state the
desire for 3rd party suppliers of PID boxes and a lack of worrying
about supply problems in the future, etc.  But isn't that exactly what
you get when you make it, yourself?

Is the real reason because they don't believe you've really got all
the "quirks" worked out and they don't want to take risks that there
will be a lot more time needed to shake out what you've already done?

Small or first-time suppliers will be "risky" from that point of view,
I suppose.  So which larger manufacturers have you already looked at,
what devices, and why aren't they suitable?  That would also help a
lot, for whomever tries to answer you effectively.

Tim Wescott may have a great deal to add to all this, but frankly I'm
in need of more information before having any idea what to recommend,
technically.

Jon

Jamie wrote:
> As it said.
>   We need to replace some analog PID boards due to supply and
> side effects the existing ones have.
> 
>   The PID code that comes in digital drives and process controllers
> are pretty much what we're looking for how ever, we only need just
> a design that allows a input ref, reference feed back and a output
> to drive what ever device.
>  This device should have it's own mini LCD interface to set the
> values or at least a computer hook up to do so.
> 
>   It should have the standard Proportional Gain, Integral and
> derivative components to set the values.
> 
>   Also, having an option to select unipolar and bipolar output
> is a plus!..
> 

Up to here it sounds like that is feasible with programmable logic 
controllers (PLC). Allen-Bradley, Danaher, Omron, Siemens and many 
others. But it depends how fast your loop needs to be.


>  I know there are various analog boards out there already that
> do this how ever, We have found that they seem to exhibit side
> effects and cause self oscillation under some conditions.
> 
>  In the digital varieties, I have found this not to be a problem
> because it's being done via software and thus these effects are not 
> visible.
> 
>  I have already made a few using a AVR/ATMega that employ the ADC inputs 
> and we simply buffer the output into a PWM filter and op-amp.
>   These units are programmed via a serial connection for the params.
> 
>  How ever, my employer wants to buy units that are ready made so that
> replacements can be had with out depending on in-house designs.
> 

Why? Put an LCD and buttons on them, have them produced, use as many as 
needed for your purposes and sell the rest like hot cakes, make oodles 
of money. Ask your employer for a 2-3% revenue sharing incentive, buy a 
tropical island, a LearJet, a few crates of margarita mix, then retire.


>   I have looked and I can't find a unit that has a build on LCD display
> with a simple interface to do this..
> 
>  We do have a SSD out board key pad unit that does do this function for 
> us along with some other little nifty things how ever, it appears that 
> this unit is no longer available.
> 
>  Any idea's?
> 

PLC can do all that if your loop timing isn't super fast. But they cost 
a pretty penny and usually every ever so little extra such as LCD, 
ADC/DAC or keypad costs extra. Oh, you want a steering wheel with that 
car? That's be another $100. Maybe you can find a budget version that 
has at least a tiny LCD and 4-5 buttons.

Boxes geared more towards PID:

http://www.alliedelec.com/Images/Products/Datasheets/BM/OMRON_ELECTRONICS_INC/834-0360.PDF
http://news.thomasnet.com/fullstory/453366

-- 
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.

On Jul 2, 6:46=A0am, Joerg <inva...@invalid.invalid> wrote:
> Jamie wrote:
> > As it said.
> > =A0 We need to replace some analog PID boards due to supply and
> > side effects the existing ones have.
>
> > =A0 The PID code that comes in digital drives and process controllers
> > are pretty much what we're looking for how ever, we only need just
> > a design that allows a input ref, reference feed back and a output
> > to drive what ever device.
> > =A0This device should have it's own mini LCD interface to set the
> > values or at least a computer hook up to do so.
>
> > =A0 It should have the standard Proportional Gain, Integral and
> > derivative components to set the values.
>
> > =A0 Also, having an option to select unipolar and bipolar output
> > is a plus!..

That's exactly what we have:

http:linnix.com/pid.jpg

LCD, LM358 A2D, 2 or 4 buttons, 10 pins external interface.

>
> Up to here it sounds like that is feasible with programmable logic
> controllers (PLC). Allen-Bradley, Danaher, Omron, Siemens and many
> others. But it depends how fast your loop needs to be.

We get several hundred hertz closed-loop responses.

>
> > =A0I have already made a few using a AVR/ATMega that employ the ADC inp=
uts

We did so too.  But AVRs are too expensive.

> Why? Put an LCD and buttons on them, have them produced, use as many as
> needed for your purposes and sell the rest like hot cakes, make oodles
> of money. Ask your employer for a 2-3% revenue sharing incentive, buy a
> tropical island, a LearJet, a few crates of margarita mix, then retire.

We can customize it for the OP.
>
> PLC can do all that if your loop timing isn't super fast. But they cost
> a pretty penny and usually every ever so little extra such as LCD,
> ADC/DAC or keypad costs extra. Oh, you want a steering wheel with that
> car? That's be another $100. Maybe you can find a budget version that
> has at least a tiny LCD and 4-5 buttons.
>

We sell them for less than $10.  It would need huge qty to afford the
island, jet, etc.

linnix wrote:
> On Jul 2, 6:46 am, Joerg <inva...@invalid.invalid> wrote:
>> Jamie wrote:
>>> As it said.
>>>   We need to replace some analog PID boards due to supply and
>>> side effects the existing ones have.
>>>   The PID code that comes in digital drives and process controllers
>>> are pretty much what we're looking for how ever, we only need just
>>> a design that allows a input ref, reference feed back and a output
>>> to drive what ever device.
>>>  This device should have it's own mini LCD interface to set the
>>> values or at least a computer hook up to do so.
>>>   It should have the standard Proportional Gain, Integral and
>>> derivative components to set the values.
>>>   Also, having an option to select unipolar and bipolar output
>>> is a plus!..
> 
> That's exactly what we have:
> 
> http:linnix.com/pid.jpg
> 
> LCD, LM358 A2D, 2 or 4 buttons, 10 pins external interface.
> 

Does it have a DAC as well so you can control the analog plant input?


>> Up to here it sounds like that is feasible with programmable logic
>> controllers (PLC). Allen-Bradley, Danaher, Omron, Siemens and many
>> others. But it depends how fast your loop needs to be.
> 
> We get several hundred hertz closed-loop responses.
> 

That is sufficient for many if not most process control jobs.


>>>  I have already made a few using a AVR/ATMega that employ the ADC inputs
> 
> We did so too.  But AVRs are too expensive.
> 
>> Why? Put an LCD and buttons on them, have them produced, use as many as
>> needed for your purposes and sell the rest like hot cakes, make oodles
>> of money. Ask your employer for a 2-3% revenue sharing incentive, buy a
>> tropical island, a LearJet, a few crates of margarita mix, then retire.
> 
> We can customize it for the OP.
>> PLC can do all that if your loop timing isn't super fast. But they cost
>> a pretty penny and usually every ever so little extra such as LCD,
>> ADC/DAC or keypad costs extra. Oh, you want a steering wheel with that
>> car? That's be another $100. Maybe you can find a budget version that
>> has at least a tiny LCD and 4-5 buttons.
>>
> 
> We sell them for less than $10.  It would need huge qty to afford the
> island, jet, etc.


Now you've piqued my interest. Is there a datasheet of the unit and 
maybe a photo with housing? Maybe a little more in focus, the one in the 
link looks like it was taken after a meeting with Jose Cuervo ;-)

-- 
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.

On Jul 2, 8:57=A0am, Joerg <inva...@invalid.invalid> wrote:
> linnix wrote:
> > On Jul 2, 6:46 am, Joerg <inva...@invalid.invalid> wrote:
> >> Jamie wrote:
> >>> As it said.
> >>> =A0 We need to replace some analog PID boards due to supply and
> >>> side effects the existing ones have.
> >>> =A0 The PID code that comes in digital drives and process controllers
> >>> are pretty much what we're looking for how ever, we only need just
> >>> a design that allows a input ref, reference feed back and a output
> >>> to drive what ever device.
> >>> =A0This device should have it's own mini LCD interface to set the
> >>> values or at least a computer hook up to do so.
> >>> =A0 It should have the standard Proportional Gain, Integral and
> >>> derivative components to set the values.
> >>> =A0 Also, having an option to select unipolar and bipolar output
> >>> is a plus!..
>
> > That's exactly what we have:
>

http://linnix.com/pid.jpg

>
> > LCD, LM358 A2D, 2 or 4 buttons, 10 pins external interface.
>
> Does it have a DAC as well so you can control the analog plant input?

Yes, half of the LM358 is unused.  It can be customized as another A2D
or an external integrator for better responds.

>
> >> Up to here it sounds like that is feasible with programmable logic
> >> controllers (PLC). Allen-Bradley, Danaher, Omron, Siemens and many
> >> others. But it depends how fast your loop needs to be.
>
> > We get several hundred hertz closed-loop responses.
>
> That is sufficient for many if not most process control jobs.
>
>
>
>
>
> >>> =A0I have already made a few using a AVR/ATMega that employ the ADC i=
nputs
>
> > We did so too. =A0But AVRs are too expensive.
>
> >> Why? Put an LCD and buttons on them, have them produced, use as many a=
s
> >> needed for your purposes and sell the rest like hot cakes, make oodles
> >> of money. Ask your employer for a 2-3% revenue sharing incentive, buy =
a
> >> tropical island, a LearJet, a few crates of margarita mix, then retire=
.
>
> > We can customize it for the OP.
> >> PLC can do all that if your loop timing isn't super fast. But they cos=
t
> >> a pretty penny and usually every ever so little extra such as LCD,
> >> ADC/DAC or keypad costs extra. Oh, you want a steering wheel with that
> >> car? That's be another $100. Maybe you can find a budget version that
> >> has at least a tiny LCD and 4-5 buttons.
>
> > We sell them for less than $10. =A0It would need huge qty to afford the
> > island, jet, etc.
>
> Now you've piqued my interest. Is there a datasheet of the unit and
> maybe a photo with housing? Maybe a little more in focus, the one in the
> link looks like it was taken after a meeting with Jose Cuervo ;-)

Not yet, but we have discussed many issues here in CAE or SEC

Most recently, the supply voltage issue.  It is now happily running a
4.2V LDO (better) or LM317 (cheaper) regulator for the op amp and
sensor, minus a BAV99 drop for the 16K OTP ASIC.  The LCD is nice and
clear at 3.6V.

On Wed, 01 Jul 2009 17:43:30 -0700, linnix wrote:

> On Jul 2, 6:46 am, Joerg <inva...@invalid.invalid> wrote:
>> Jamie wrote:
>> > As it said.
>> >   We need to replace some analog PID boards due to supply and
>> > side effects the existing ones have.
>>
>> >   The PID code that comes in digital drives and process controllers
>> > are pretty much what we're looking for how ever, we only need just a
>> > design that allows a input ref, reference feed back and a output to
>> > drive what ever device.
>> >  This device should have it's own mini LCD interface to set the
>> > values or at least a computer hook up to do so.
>>
>> >   It should have the standard Proportional Gain, Integral and
>> > derivative components to set the values.
>>
>> >   Also, having an option to select unipolar and bipolar output
>> > is a plus!..
> 
> That's exactly what we have:
> 
> http:linnix.com/pid.jpg
> 
> LCD, LM358 A2D, 2 or 4 buttons, 10 pins external interface.
> 
> 
>> Up to here it sounds like that is feasible with programmable logic
>> controllers (PLC). Allen-Bradley, Danaher, Omron, Siemens and many
>> others. But it depends how fast your loop needs to be.
> 
> We get several hundred hertz closed-loop responses.
> 
> 
>> >  I have already made a few using a AVR/ATMega that employ the ADC
>> >  inputs
> 
> We did so too.  But AVRs are too expensive.
> 
>> Why? Put an LCD and buttons on them, have them produced, use as many as
>> needed for your purposes and sell the rest like hot cakes, make oodles
>> of money. Ask your employer for a 2-3% revenue sharing incentive, buy a
>> tropical island, a LearJet, a few crates of margarita mix, then retire.
> 
> We can customize it for the OP.
>>
>> PLC can do all that if your loop timing isn't super fast. But they cost
>> a pretty penny and usually every ever so little extra such as LCD,
>> ADC/DAC or keypad costs extra. Oh, you want a steering wheel with that
>> car? That's be another $100. Maybe you can find a budget version that
>> has at least a tiny LCD and 4-5 buttons.
>>
>>
> We sell them for less than $10.  It would need huge qty to afford the
> island, jet, etc.

But your main page -- www.linnix.com -- announces "Hi there, we don't 
want you as a customer".

Or at least it only wants customers who are willing to log in blind to an 
unknown site.

-- 
http://www.wescottdesign.com

On Wed, 01 Jul 2009 19:26:03 +0000, Jon Kirwan wrote:

> On Wed, 01 Jul 2009 14:14:47 -0400, Jamie
> <j...@charter.net> wrote:
> 
>><snip about PID>
>>  Any idea's?
> 
> No ideas.  Some comments.
> 
> I'm not clear about exactly how you are using these PID units, right
> now.  It almost sounds as though you are an off-the-shelf consumer of
> PID controllers with a specific process to control -- except for the
> fact that you talk about unipolar and bipolar operation being a plus,
> which suggests that you have a variety of situations to deal with and
> not just the one.  That makes me imagine you more in the position of not
> really knowing where the PID is being applied and that you want a more
> general solution as an OEM supplier to end users (which implies you
> aren't the end user of the PID.)  Are you and end-user or do you supply
> something to others that must include PID as a feature?
> 
> You also mention self-oscillation, which is a fairly common problem I've
> seen with PID -- especially where there is a significant time delay in
> the loop.  One of the cheaper ways to handle that is to simply shorten
> the delay.  Even a brain-dead PID controller can do a credible job on
> controlling a process where the loop time is shorter and repeatable.
> 
> You mention having created a solution with an ATmega that works already,
> but that your company doesn't want to use it.  Instead preferring to buy
> something on the outside.  Why?  Many would very much like to be in
> control of something like this.  You state the desire for 3rd party
> suppliers of PID boxes and a lack of worrying about supply problems in
> the future, etc.  But isn't that exactly what you get when you make it,
> yourself?
> 
> Is the real reason because they don't believe you've really got all the
> "quirks" worked out and they don't want to take risks that there will be
> a lot more time needed to shake out what you've already done?
> 
> Small or first-time suppliers will be "risky" from that point of view, I
> suppose.  So which larger manufacturers have you already looked at, what
> devices, and why aren't they suitable?  That would also help a lot, for
> whomever tries to answer you effectively.
> 
> Tim Wescott may have a great deal to add to all this, but frankly I'm in
> need of more information before having any idea what to recommend,
> technically.
> 
> Jon

Cynicism, mostly.

Outsourcing wisdom says that you do your 'core competencies' and you farm 
out the rest.  As an employee, I saw innumerable times when management 
farmed out stuff to 'experts' who completely failed to understand the 
needs of the company, failed miserably at what they signed up to do, and 
ended up doing nothing but costing money and causing grief.  (In fact, 
I'm getting paid good money now to fix up one of those for a client).  As 
a consultant, I see over and over again when an in-house design effort 
fails, gets pushed far too far, and management only panics and calls me 
in after it's too late to do much but wrap bandages in an intelligent and 
thoughtful manner.

I only know of two dedicated embedded PID controllers, including the 
linnix one.  The one example of this that I've worked with was pretty 
pedestrian; in many cases you could just read my PID article and roll 
your own -- anything you lost in PID expertise you'd gain back with an 
intimate knowledge of how your own system.

I think, frankly, that the reason you don't see more is because it _is_ 
so easy to tuck a PID controller into the corner of a larger general-
purpose embedded controller -- so why go buy one special?

It'd be interesting to see what linnix has to offer, if the site would 
cough up more than a few lousy pictures.

-- 
http://www.wescottdesign.com

Tim Wescott wrote:

[...]

> I only know of two dedicated embedded PID controllers, including the 
> linnix one.  The one example of this that I've worked with was pretty 
> pedestrian; in many cases you could just read my PID article and roll 
> your own -- anything you lost in PID expertise you'd gain back with an 
> intimate knowledge of how your own system.
> 
> I think, frankly, that the reason you don't see more is because it _is_ 
> so easy to tuck a PID controller into the corner of a larger general-
> purpose embedded controller -- so why go buy one special?
> 

The market would be companies like Jamie's. For whatever reason, 
liabitity, procurement, whatever, they don't want to roll their own. 
Other times there just isn't anyone who can program a uC. But most of 
all people want this:

Something that drops in, does not have potmeters that can get screwed 
up, can be pre-programmed and shipped, and has mounting screw holes as 
well as screw terminals. For high rollers maybe even a clickable DIN 
rail version.


> It'd be interesting to see what linnix has to offer, if the site would 
> cough up more than a few lousy pictures.
> 

He said they'll have discussions, probably how much and when to release 
info. Eagerly awaiting that ...

-- 
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.

On Jul 2, 11:16=A0am, Joerg <inva...@invalid.invalid> wrote:
> Tim Wescott wrote:
>> But your main page -- www.linnix.com -- announces "Hi there, we don't
>> want you as a customer".

Actually, it says we are too busy to make fancy web pages.  The main
page log into our email system only.  Our customers know were to look
for subfolders.  We will update more for this later.

>
> [...]
>
> > I only know of two dedicated embedded PID controllers, including the
> > linnix one. =A0The one example of this that I've worked with was pretty
> > pedestrian; in many cases you could just read my PID article and roll
> > your own -- anything you lost in PID expertise you'd gain back with an
> > intimate knowledge of how your own system.
>
> > I think, frankly, that the reason you don't see more is because it _is_
> > so easy to tuck a PID controller into the corner of a larger general-
> > purpose embedded controller -- so why go buy one special?
>
> The market would be companies like Jamie's. For whatever reason,
> liabitity, procurement, whatever, they don't want to roll their own.
> Other times there just isn't anyone who can program a uC. But most of
> all people want this:

Unlike Flash, OTP development cost is very high.  I don't think many
people want to deal with it.  But volume production cost is much
lower.  The entire BOM for this board is $2 to $3, same as the 10K
price for the Flash based LCD AVR chip alone.

>
> Something that drops in, does not have potmeters that can get screwed
> up, can be pre-programmed and shipped, and has mounting screw holes as
> well as screw terminals. For high rollers maybe even a clickable DIN
> rail version.
>
> > It'd be interesting to see what linnix has to offer, if the site would
> > cough up more than a few lousy pictures.

Give me more time, please.

>
> He said they'll have discussions, probably how much and when to release
> info. Eagerly awaiting that ...

Right now, I am busy trying to solve the external integrator problem.
Our customer needs better closed-loop response with hardware
integrator.  At the end of a cycle, I need a high resistant switch to
discharge the capacitor.  The MOSFET I tried did not isolate well
enough.  Mechanical relay works, but size is a problem.  I need a
SOT-23-5 sized semiconductor relay.  Any suggestions?