Reply by Michael A. Terrell January 20, 20142014-01-20
Jim Thompson wrote:
> > Real men use a Nichol's chart >:-}
And know how to use a blue wrench. :) -- Anyone wanting to run for any political office in the US should have to have a DD214, and a honorable discharge.
Reply by Jim Thompson January 19, 20142014-01-19
On Sun, 19 Jan 2014 18:41:10 -0500, Spehro Pefhany
<speffSNIP@interlogDOTyou.knowwhat> wrote:

>On Sun, 19 Jan 2014 16:09:39 -0700, the renowned Jim Thompson ><To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >
[snip]
>> >>Real men use a Nichol's chart >:-} >> >> ...Jim Thompson > >I'm pretty sure PID is in there between Locksmithing and Small Engine >Repair. > > > >Best regards, >Spehro Pefhany
Reminds me of when a ran my power mower over a sewer clean-out and bent the crank :-( Bought a new crank and piston assembly from Sears (this would have been around 1963) and put the thing back together. But I couldn't get it all to cinch up properly, so I started it up anyway, then tightened up the head, etc. Ran perfectly after that ;-) ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
Reply by Spehro Pefhany January 19, 20142014-01-19
On Sun, 19 Jan 2014 16:09:39 -0700, the renowned Jim Thompson
<To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:

>On Sun, 19 Jan 2014 14:37:21 -0800 (PST), gyansorova@gmail.com wrote: > >>On Monday, January 20, 2014 9:16:56 AM UTC+13, Spehro Pefhany wrote: >>> On Sun, 19 Jan 2014 11:14:23 -0800 (PST), the renowned >>> >>> gyansorova@gmail.com wrote: >>> >>> >>> >>> > >>> >>> >Actually wrong, it's the academics that perpetuate the PID rubbish. >>> >>> >>> >>> I have yet to see a real controls academic that considers PID remotely >>> >>> interesting. Maybe at trade schools, check your matchbook covers. >>> >>> >>> >>> >> >>Well you're talking about the fancy research stuff, but students still need to know the basics too and I gather they do all learn about PID and a little of the lag-lead stuff which is far more of use. Trades people aren't much use because they don't know what's going on most of the time, though I am sure they could tune a PID. Academics will draw you a root-locus some of the time of course which is totally useless! You don't need fancy control algorithms for most small problems but for some (eg control of the Euro-fighter and missile guidance) the modern stuff does get used, so don't knock it. Amateurs are even using Kalman filters in embedded systems nowadays (for inertial measurement). In the 1970s these were Ph.D topics. >> > >Real men use a Nichol's chart >:-} > > ...Jim Thompson
I'm pretty sure PID is in there between Locksmithing and Small Engine Repair. Best regards, Spehro Pefhany -- "it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
Reply by Jim Thompson January 19, 20142014-01-19
On Sun, 19 Jan 2014 14:37:21 -0800 (PST), gyansorova@gmail.com wrote:

>On Monday, January 20, 2014 9:16:56 AM UTC+13, Spehro Pefhany wrote: >> On Sun, 19 Jan 2014 11:14:23 -0800 (PST), the renowned >> >> gyansorova@gmail.com wrote: >> >> >> >> > >> >> >Actually wrong, it's the academics that perpetuate the PID rubbish. >> >> >> >> I have yet to see a real controls academic that considers PID remotely >> >> interesting. Maybe at trade schools, check your matchbook covers. >> >> >> >> > >Well you're talking about the fancy research stuff, but students still need to know the basics too and I gather they do all learn about PID and a little of the lag-lead stuff which is far more of use. Trades people aren't much use because they don't know what's going on most of the time, though I am sure they could tune a PID. Academics will draw you a root-locus some of the time of course which is totally useless! You don't need fancy control algorithms for most small problems but for some (eg control of the Euro-fighter and missile guidance) the modern stuff does get used, so don't knock it. Amateurs are even using Kalman filters in embedded systems nowadays (for inertial measurement). In the 1970s these were Ph.D topics. >
Real men use a Nichol's chart >:-} ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
Reply by January 19, 20142014-01-19
On Monday, January 20, 2014 9:16:56 AM UTC+13, Spehro Pefhany wrote:
> On Sun, 19 Jan 2014 11:14:23 -0800 (PST), the renowned >=20 > gyansorova@gmail.com wrote: >=20 >=20 >=20 > > >=20 > >Actually wrong, it's the academics that perpetuate the PID rubbish. >=20 >=20 >=20 > I have yet to see a real controls academic that considers PID remotely >=20 > interesting. Maybe at trade schools, check your matchbook covers.=20 >=20 >=20 >=20 >=20
Well you're talking about the fancy research stuff, but students still need= to know the basics too and I gather they do all learn about PID and a litt= le of the lag-lead stuff which is far more of use. Trades people aren't muc= h use because they don't know what's going on most of the time, though I am= sure they could tune a PID. Academics will draw you a root-locus some of t= he time of course which is totally useless! You don't need fancy control al= gorithms for most small problems but for some (eg control of the Euro-fight= er and missile guidance) the modern stuff does get used, so don't knock it.= Amateurs are even using Kalman filters in embedded systems nowadays (for i= nertial measurement). In the 1970s these were Ph.D topics.
Reply by Spehro Pefhany January 19, 20142014-01-19
On Sun, 19 Jan 2014 11:14:23 -0800 (PST), the renowned
gyansorova@gmail.com wrote:

> >Actually wrong, it's the academics that perpetuate the PID rubbish.
I have yet to see a real controls academic that considers PID remotely interesting. Maybe at trade schools, check your matchbook covers. Best regards, Spehro Pefhany -- "it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
Reply by January 19, 20142014-01-19
On Monday, January 20, 2014 4:41:29 AM UTC+13, Jim Thompson wrote:
> On Sun, 19 Jan 2014 01:10:52 -0800 (PST), gyansorova@gmail.com wrote: >=20 >=20 >=20 > >On Thursday, January 16, 2014 2:23:09 AM UTC+13, hon...@yahoo.com wrote: >=20 > >> I know about the auto-tuning algorithm for PID: cycle the temperature =
up and down, measure the peaks and distance between the peaks, and calculat= e Kp, Ki, and Kd. =20
>=20 > >>=20 >=20 > >>=20 >=20 > >>=20 >=20 > >> But recently I've been experimenting with what Phelan called PDF, and =
am intrigued by it. There isn't a lot of information out there about it, b= ut nearly everyone that's used it has good things to say. =20
>=20 > >>=20 >=20 > >>=20 >=20 > >>=20 >=20 > >> The problem is, how is it tuned? It only has a Ki and Kd, so that mak=
es it slightly simpler. An auto-tune algo like the one I just mentioned wo= uld be great, or at the very least, some general guide for manual tuning. = A method that doesn't mention poles, zeros, or transforms would be nice bec= ause even though I have an EE degree, my strong point isn't controls. =20
>=20 > >>=20 >=20 > >>=20 >=20 > >>=20 >=20 > >> Either I forgot everything in my controls class or never learned it, I=
don't know which.
>=20 > > >=20 > >All this tuning stuff is nonsense. You draw a Bode plot of your system a=
nd design properly the controller. Tuning is for amateurs.
>=20 >=20 >=20 > And you sound like an academician who's never actually BUILT >=20 > anything... just paper doodles. >=20 >=20
Actually wrong, it's the academics that perpetuate the PID rubbish. There r= ae many problems with this approach. The main problem is for electro-mechan= ical systems is that you have no concept of bandwidth. You are measuring ve= ry little. Time-domain design is futile. I admit if you are designing say s= ome form of chemical plant then that makes sense, since you have little kno= wledge of the plant and it is very slow anyway. Look at how a hard disk dri= ve is designed and that is how its done. Watch out for the structural reson= ance, that is the key point.
Reply by Jim Thompson January 19, 20142014-01-19
On Sun, 19 Jan 2014 13:15:26 -0500, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

>On 1/19/2014 10:41 AM, Jim Thompson wrote: >> On Sun, 19 Jan 2014 01:10:52 -0800 (PST), gyansorova@gmail.com wrote: >> >>> On Thursday, January 16, 2014 2:23:09 AM UTC+13, hon...@yahoo.com wrote: >>>> I know about the auto-tuning algorithm for PID: cycle the temperature up and down, measure the peaks and distance between the peaks, and calculate Kp, Ki, and Kd. >>>> >>>> >>>> >>>> But recently I've been experimenting with what Phelan called PDF, and am intrigued by it. There isn't a lot of information out there about it, but nearly everyone that's used it has good things to say. >>>> >>>> >>>> >>>> The problem is, how is it tuned? It only has a Ki and Kd, so that makes it slightly simpler. An auto-tune algo like the one I just mentioned would be great, or at the very least, some general guide for manual tuning. A method that doesn't mention poles, zeros, or transforms would be nice because even though I have an EE degree, my strong point isn't controls. >>>> >>>> >>>> >>>> Either I forgot everything in my controls class or never learned it, I don't know which. >>> >>> All this tuning stuff is nonsense. You draw a Bode plot of your system and design properly the controller. Tuning is for amateurs. >> >> And you sound like an academician who's never actually BUILT >> anything... just paper doodles. >> >> The real world is non-linear. >> >> ...Jim Thompson >> > >It also benefits from those local loops we've been talking about. For >instance, if you have two loop components that both have 2:1 gain >variations over their working range but are faster than the rest, a >single large loop has to be slowed down ridiculously to maintain >stability. OTOH, if you use local loops, you can make the outer loop >something like four times faster, and get much improved transient response. > >There are lots of things that are hard to calculate from first >principles, e.g. the transient response of a multi-stage TEC. > >Cheers > >Phil Hobbs
Yep. In my ASIC designs, transistors are dirt cheap, so I really go hog-wild with local loops so that my building blocks approach ideal performance. ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
Reply by Phil Hobbs January 19, 20142014-01-19
On 1/19/2014 10:41 AM, Jim Thompson wrote:
> On Sun, 19 Jan 2014 01:10:52 -0800 (PST), gyansorova@gmail.com wrote: > >> On Thursday, January 16, 2014 2:23:09 AM UTC+13, hon...@yahoo.com wrote: >>> I know about the auto-tuning algorithm for PID: cycle the temperature up and down, measure the peaks and distance between the peaks, and calculate Kp, Ki, and Kd. >>> >>> >>> >>> But recently I've been experimenting with what Phelan called PDF, and am intrigued by it. There isn't a lot of information out there about it, but nearly everyone that's used it has good things to say. >>> >>> >>> >>> The problem is, how is it tuned? It only has a Ki and Kd, so that makes it slightly simpler. An auto-tune algo like the one I just mentioned would be great, or at the very least, some general guide for manual tuning. A method that doesn't mention poles, zeros, or transforms would be nice because even though I have an EE degree, my strong point isn't controls. >>> >>> >>> >>> Either I forgot everything in my controls class or never learned it, I don't know which. >> >> All this tuning stuff is nonsense. You draw a Bode plot of your system and design properly the controller. Tuning is for amateurs. > > And you sound like an academician who's never actually BUILT > anything... just paper doodles. > > The real world is non-linear. > > ...Jim Thompson >
It also benefits from those local loops we've been talking about. For instance, if you have two loop components that both have 2:1 gain variations over their working range but are faster than the rest, a single large loop has to be slowed down ridiculously to maintain stability. OTOH, if you use local loops, you can make the outer loop something like four times faster, and get much improved transient response. There are lots of things that are hard to calculate from first principles, e.g. the transient response of a multi-stage TEC. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net
Reply by Jim Thompson January 19, 20142014-01-19
On Sun, 19 Jan 2014 01:10:52 -0800 (PST), gyansorova@gmail.com wrote:

>On Thursday, January 16, 2014 2:23:09 AM UTC+13, hon...@yahoo.com wrote: >> I know about the auto-tuning algorithm for PID: cycle the temperature up and down, measure the peaks and distance between the peaks, and calculate Kp, Ki, and Kd. >> >> >> >> But recently I've been experimenting with what Phelan called PDF, and am intrigued by it. There isn't a lot of information out there about it, but nearly everyone that's used it has good things to say. >> >> >> >> The problem is, how is it tuned? It only has a Ki and Kd, so that makes it slightly simpler. An auto-tune algo like the one I just mentioned would be great, or at the very least, some general guide for manual tuning. A method that doesn't mention poles, zeros, or transforms would be nice because even though I have an EE degree, my strong point isn't controls. >> >> >> >> Either I forgot everything in my controls class or never learned it, I don't know which. > >All this tuning stuff is nonsense. You draw a Bode plot of your system and design properly the controller. Tuning is for amateurs.
And you sound like an academician who's never actually BUILT anything... just paper doodles. The real world is non-linear. ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.