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## Control system shapes

Started by Paul Herber, August 01, 2017, 08:59:44 AM

0 Members and 1 Guest are viewing this topic.

#### Paul Herber

A question on the SuperUser forum prompted me to create these simple shapes for generating control system diagrams:

http://www.paulherber.co.uk/articles/visio-articles/control-systems/

No feedback required about these shapes (postive or negative).
Electronic and Electrical engineering, business and software stencils for Visio -

https://www.paulherber.co.uk/

#### wapperdude

Those shapes are all about feedback...positive or negative...mostly negative...I'm pretty positive about that...

Wapperdude
Visio 2019 Pro

#### vojo

nice

But wouldn't you want look at doing some actual math?   Much like Junes shapes.
I know passing values between shapes in Visio is tough...but it would make these shapes "killer shapes"

#### Yacine

@Vojo, nice thought.
I wonder however what you would like to get automated?
A real control simulation would probably be too difficult to program. Isn't it.
Yacine

#### vojo

so if one could pass values between shapes (special connector or whatever)...you could
- create shapes (summing shape, anding shape, amplifier shape, etc)
- put actual numbers on the links
- etc

So your example diagram would have values and show an actual result

You may want to talk June, I think he did something like this a few years ago.

#### metuemre

Hard to do but not impossible

#### wapperdude

Haven't checked the video yet...but, the math in a control system is not simple, if you're going to do an actual modelling...LaPlace / Fourier transforms, sampling, etc.  Visio makes a nice documentation tool, but it is not an analytical tool.

Wapperdude
Visio 2019 Pro

#### Paul Herber

If just numbers were involved it might be possible, but the formulae used are normally very complex. I'm not sure even Excel could handle the calculations. It's more the domain of mathematical modeling software.
Electronic and Electrical engineering, business and software stencils for Visio -

https://www.paulherber.co.uk/

#### wapperdude

For what it's worth...Excel can analyze the math.  It took about a year, part time, to develop, but I was able to create an Excel PLL analysis program back in the 90's, of course.  It was limited to 2nd order, type 3 systems as I recall.  Definitely an involved task.

Wapperdude
Visio 2019 Pro

#### Yacine

#10
Agree with Paul. Tagging will be the least of the problems.
The simulation - the really interesting part - is the real issue.

I've been playing with open modelica for the last 5 years or so. Starting and stopping after some months, again and again. The models I handle (Custom made confectionery lines) are so complex and involve so many disciplines, that I cannot really elaborate by myself a working solution. Modelica has - unlike Visio - such a small community, that you cannot get useful (fast) help. Getting a budget for professional help has - this far - been beyond my engagement. So I kept trying and failing by myself again and again.

The solution Vojo suggests would (could) involve modelling the system in Visio, send it to Modelica and get back the results. A connection to Visio - altough it existed in the early days of openmodelica - is badly documented (actually "impossible").

The issue is, Modelica (or better its implementations as openmodelica, simulationX, ...) have their own visualisation tools and therefore would not require Visio.
My (preliminary) conclusion for the subject would be: If someone uses Visio for control loops, then it will always be for a "dumb" visualisation. The intelligence being in a textual explanation.
Intelligent systems will bring their own visualisation.

https://www.openmodelica.org/
https://www.simulationx.com/

PS: control loops are - unlike fluid systems - already quite good developed in openmodelica. Really worth a look. (Wayne, Paul, ...)
Yacine

#### vojo

hey guys, what ever

Sure, modelling schrodingers equation would be difficult and sequency analysis for discrete convolution is doable but useless

But discrete systems (Z transforms, sampled data, LUTs) should not be tough (and makes the hand off the tough part

It was just a thought....

BTW if excel involved, just put the drawing in an excel sheet using excel shapes
Or if a continuous system, use python or mathlab to evaluate an equation for a countinuous system over a range

#### metuemre

I got some free time and decided to give it a try. Results are not bad compared to Simulink

Problem is the execution speed. I set the speed to "40 iteration/second" which takes 25 seconds for 1000 iteration whereas it takes smaller than a second in Matlab.

I will post the sample visio file with necessary references tomorrow if someone wants to try.

#### Paul Herber

Electronic and Electrical engineering, business and software stencils for Visio -

https://www.paulherber.co.uk/

#### Yacine

+1
Yacine

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