PID filter coefficient output minimum, maximum and parameter attributes

Question

I am trying to find more information on making a custom PID block in MATLAB. I have most of it done but there are a few parameters that I don't really understand and as such I don't know what value to give them. NOTE I am NOT asking for help tuning PID gains.

They are all inside the filter coefficient block:

When I open the block I have to set a few parameters (output min/max, data type, parameter min/max, etc.). Can someone explain to me what these mean? I can't find good resources anywhere. The only thing that I've tried which works is setting each to [] (i.e. -inf) and the input/output data types to 'Inherit: Inherit via internal rule' but then my output goes to hell. If I copy paste the blocks from the PID block there are a bunch of variables which I haven't defined anywhere so the program won't even compile. Can someone point out some good resources for this or else explain it? Thanks!

Answer 1

You should get your blocks from the standard Simulink library, not from under the PID block mask. The ones under the mask have been set-up to use variables that are passed from/through the mask, which you are not doing.

The block you have circled is just a gain block (from the Math library). You most likely won't need to make any changes to the default settings of the block other than the constant value (which needs to be the N that you want to use in the approximation of the derivative term in your controller).

To answer your specific question about what the parameters are, some of them are used to specify data types (if you don't want to use the default double precision), some are only used in code generation, some others only for other specific tasks. All of them are described (in more, or sometimes less, detail) in the doc for the block, obtained by pressing the help button on the block's dialog.