Shameless Plug

I will be presenting two topics at the 2005 Embedded Systems Conference San Francisco next March -- see http://www.esconline.com/sf/ for show
details.
"Basic Control Theory for the Software Engineer" is as much information on the z-transform as I can fit into 90 minutes. It gives a high-altitude overview of designing software control loops in a systematic manner.
"PID Without a PhD" is a primer on developing PID controllers in software, tuning them without using higher math, and avoiding some of the common pitfalls for this popular controller form.
--

Tim Wescott
Wescott Design Services
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Mon, 29 Nov 2004 16:43:55 -0800, Tim Wescott

I would sure like to receive copies of each!
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Jim Thompson wrote:

The source material for both is on my website -- http://www.wescottdesign.com/articles/pidwophd.html gets you one click away, and http://www.wescottdesign.com/articles/zTransform/z-transforms.html is the z-domain stuff.
--

Tim Wescott
Wescott Design Services
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Mon, 29 Nov 2004 17:22:07 -0800, Tim Wescott

Thanks, Tim. I last took a non-linear control systems course in 1968, but I actually enjoyed it, still have my notes ;-)
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Hi Tim,
Just let us know what day and time. Do you plan to publish these? The PID session sounds very interesting.
BTW, Scott Adams (Dilbert) is going to speak as well.
Regards, Joerg
http://www.analogconsultants.com
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Tim Wescott wrote:

Cool! From many years teaching "practical PID" to technicians and engineers, here are some questions that came up a lot:
"Why do so many of the setups around here have only P and I or have D set to zero? How do I decide when to use D?"
"Why do some controller boards have an option to reverse the phase of the D? What is that good for?"
"How do I describe a thermostat with hysteresis using the same language that I use to describe a PID controller? It seems like P is infinity."
"Why do half the engineers call it Proportional-Integral-Derivative" and others call it "Proportional-Integral-Differential?" When I did a Google search on "proportional integral differential" I got 18,600 hits while "proportional integral differential" only had 3,060 hits, but most of the "proportional integral differential" hits seem to be by scientists and equipment manufacturers. Which is correct?"
BTW. for what it's worth, I found that relating position servos and velocity servos to a person controlling a car (speed and position within the lane) was helpful. I also found it helpful to show how to use a stopwatch and odometer to derive speed with no speedometer, a stopwatch and speedometer to derive distance without an odometer, and a speedometer and odometer to derive elapsed time with no stopwatch. Your audience is different, of course - this worked really well with mechanical engineers, but software engineers are quite different.
Another gotcha that sometimes trips up software engineers: non-monotonic ADCs causing a "bad spot" that has positive feedback.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Guy Macon wrote...

proportional integral derivative - 253,000 hits = correct proportional integral differential - 315,000 hits = wrong
--
Thanks,
- Win
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Try a searching the whole phrase
Google for "proportional integral derivative" gets 18,600
Google for "proportional integral differential" gets 3,060
Search for both and you get 47
It was originally Derivative, and still is to me.
message

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

In 'Control Speak':
Differential: the amount of hysteresis in an on/off controller, such as a home thermostat.
Derivative: The term D * dPV/dT in a PID controller where: D == derivative gain; PV = process variable; T == time. Some controllers use D * dE/dT where E == error.
Lesson: Half of everything is bunk.
--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer: Electronics; Informatics; Photonics.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Not acording to Sturgeon's Law:
90% of everything is C%&p
But that was before the internet - Internet Corollary to Sturgeon's Lwa:
99% of everything is C%&p
Bruce
Nicholas O. Lindan wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Francis wrote...

Phew, that's a relief.
--
Thanks,
- Win
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Winfield Hill wrote:

Please don't snip out the part where I wrote "a common question is", thus making it look as if I am the one asking asking the question.

proportional integral derivative - 253,000 hits "proportional integral derivative" - 18,600 hits proportional integral differential - 315,000 hits "proportional integral differential" - 3,060 hits
The quotation marks are important in this case. You want to count the times the phrase is used, not the times that all three words are found on different parts of the page.
I was taught that "Proportional-Integral-Derivative" is the proper term, but the Google search turns up some disturbing uses. It's in an article published in the Geotechnical Testing Journal on astm.org. It is used by Paul Brinks, who appears to be teaching a class on PID at a state univerity. It's used in a paper titled "A Closed Loop Controller for Electron-Beam Evaporators" published in _Review of Scientific Instruments_.
I still think "Proportional-Integral-Differential" is wrong, even a bunch of college boys and one out of six webpages says that it is correct. I just wonder why so many get it wrong.
--
Guy Macon <http://www.guymacon.com


Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Guy Macon wrote:

I fear that my mind was poisoned long ago by a German instructor who pointed out that modern linguistic theory doesn't much recognize a "right way" and a "wrong way" -- it just records prevalent usage, and tries to keep out of the way of the steamroller.
When I write something that has two competing terms in use I'll often mention both of them (perhaps in a footnote), and I'll explain why I use the one I do.
--

Tim Wescott
Wescott Design Services
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Tim Wescott wrote:

I tend to agree, but the "wrong way" hinders communication if it is *too* different from the "right way." If one decides to use a few non-standard fleemishes and the reader can still gloork the meaning from the context, but there ix a limit; If too many ot the vleeps are changed, it becomes harder and qixer to fllf what the wethcz is blorping, and evenually izs is bkb longer possible to ghilred frok at wifx. Dnighth? Ngfipht yk ur! Uvq the hhvd or hnnngh. Blorgk? Blorgk! Blorgkity-blorgk!!!!
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Guy Macon wrote:

Well, that's why if I know there's two markedly different ways if saying the same thing I'll footnote it.
--

Tim Wescott
Wescott Design Services
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Guy Macon wrote...

ROFLOL, LOL-LMAOXD, ROXCGHRKFITR! YUREBDH!
--
Thanks,
- Win
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
"Guy Macon" <http://www.guymacon.com wrote in message

Finally someone who speaks my language!
The first clear, concise, and lucid post in quite a while!
A little off track at first, but you wrapped it up nicely towards the end! :o)
Louis-- ********************************************* Remove the two fish in address to respond
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
["Followup-To:" header set to sci.electronics.design.] On Tue, 30 Nov 2004 08:59:24 -0800,

This reminds me of one of my favorite entries in Strunk & White, Modern English Usage on "flammable" vs. "inflammable". The correct term is inflammable, but on trucks that hold dangerous goods you'll always see "flammable". Quoting from memory: "Unless you drive such a truck, and are hence concerned with the safety of children and illiterates, use inflammable".
According to my pedantic mind, there's no such thing as a flammable substance, but the general public seems to think otherwise.
--Daniel
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Daniel Haude wrote:

The meaning of flammable is clear, while inflammable might be disastrously confused with unflammable (not a real word either) meaning non-flammable. The need for clear disambiguation on gasoline tankers trumps the joys of pedantry.
Jerry
--
Engineering is the art of making what you want from things you can get.

  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Jerry Avins to stdout:

In Portuguese, 'inflammable' would mean 'not flammable' ('in'/'im' prefix ----> 'not' as in 'impossible' == 'not possible' or 'incapable' == 'not capable').
Yet, we still use 'inflammable' (exact translation for "inflamvel")
--
Chaos Master, posting from Canoas, Brazil - 29.55 S / 51.11 W

"Sing what you can't say / forget what you can't play
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.