Simulation/Software

Hello to all.

In a previous project I captured plenty of process data, like setpoints, measurements, PID output, Lead/Lag output, and many more points. I import selected data points in Excel, I generate similiar algorithms in Excel (like PID or Lead/Lag and etc.) that simulate a loop or two similiar to the logic that generated the data, and run a macro. I compare it to the captured data and when outputs match I know the code is a match. I then inject a transient by increasing the measurement or setpoint or other and monitor output initial behavior. I also use it to change PID gains and to get a an idea of how controller will initially behave or how output behaves at steady state.

Question, doing this in Excel is very tedious because PID controller and others require previous data and the worksheet gets big. Is there software out there tailored for this? I want a software that will allow me to generate my own code and inject data from a text file and also capture the calcualted data? I don't want to spend much time putting this test together, I want to spend most of my time evaluating the data. Any help is greatly appreciated.

Thanks

Reply to
Toro
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try Scilab. It is free.

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is a user group
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There are other scientific or engineering software math packages. Octave is free too. Matlab, Maple, and Mathematic cost money

Peter Nachtwey

Reply to
pnachtwey

In article , Toro wrote: ..Is there software

Reply to
Kelvin Hales

See

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for a comparison of several packages. Octave was not included in the latest run.

Reply to
Rich Webb

Scilab and Scicos are open source packages that first come to mind. However, if you are comfortable with using Excel for analysis, then you could use VBA macros to interface to a DLL and then do all of the tedious work in another language like "C". Either way, you still have to do your own development.

Reply to
Freelance Embedded Systems Eng

That article was interesting but not as informative as it good be. There were some very important comparisons that I think are important and not addressed in the article.

  1. How the programming is done. To be fair the article done mention the programming style but it doesn't really show the difference.
  2. No mention is made of symbolic processing. I can't do without symbolic processing. Mathcad can do symbolic processing but even a free package like Maxima can out perform Mathcad.
  3. Output. It is nice is the output can be used to generate books or magazine articles. The file type is important but the quality of the output is even more important. Mathcad claims to generate html but the idiot that generated the html used Microsoft \ instead of unix // in the file paths so the Mathcad generated html files must be hosted on a Microsoft server. Linux servers can't find the image files. To fix this I must use and editor to replace the \ with /.

I have Mathcad now but I have "out grown" it and am looking to buy Maple or Mathematica. Mathematica looks like the more full featured product but the programming looks awful compared to the Pascal like Maple. However, I like the Mathematica Viewer. The user must download a player but then the Mathematica program variables can be changed by the user. I am still investigating Maple to see if it has these features. I am torn between the two. On the sci.math.symbolic use group there is a person that finds bugs in both Mathematica and Maple with equal ease. I don't want to be trading Mathcad flaws for Maple or Mathematica flaws.

The point is that the table based evaluation doesn't tell the whole story.

Peter Nachtwey

Reply to
pnachtwey

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