How to draw PI controller block diagram

Question

This is a PI controller block Diagram. How do I use this latex build this? Help

Answer 1

Let me give you a helping hand as a beginner in 3 steps.

1. Finding ways to do it

A standard way, at least for me, is to serach for it on ctan via a search engine. Even with imperfect serach terms you'll quickly naviagte to existing packages, you may want to use.

E.g. using the search term ctan block diagram provides interesting images and a perhaps useful package:

List of packages: https://ctan.org/topic/diagram-block, where schemablock might be interesting enough.

Also from here you could follow either tags, like control, search for block diagram etc., using further restrictions in the search terms.

2. Plain-Tikz drawing

Your diagram is simple enough to do it directly in Tikz. However, it needs a trick here and there which may be challenging for a novice in Tikz. I suggest to read the tutorials in parallel in the pgfmanual, and to look up statements as needed.

There are many ways to even use plain-Tikz here. The most important one may be the documentclass used: standalone:

• it's nicer to use during development
• it enables things described next

\documentclass[10pt,border=3mm,tikz]{standalone}
\usetikzlibrary {shapes.geometric}  % for nodes with triangular shape
\usetikzlibrary{arrows.meta}        % provides many arrow tips
\begin{document}
 \begin{tikzpicture}[   % self-defined styles
        blk/.style={draw,minimum width=1cm,minimum height=15mm},
        tri/.style={draw,shape=isosceles triangle, minimum height=12mm},
        > = {Stealth},
    ]
    % ~~~ coordinate ~~~~~~~~~
    \coordinate (A) at (-4,0);  % to simplify drawing the arrow
% ~~~ nodes ~~~~~~~~~~~~~~~~
\node[anchor=east]  (IN)   at (-5  , 0)  {Input}; 
\node[tri]          (P)    at (-1.5 , 1) {$p$};
\node[tri]          (K)    at (-2.5,-1)  {$k$};
\node[blk]          (S)    at ( 0  ,-1)  {\Large{$\frac{1}{s}$}};
\node[blk]          (O)    at ( 3  , 0)  {};
\node[anchor=west]  (OUT)  at ( 4.5, 0)  {Output};

% ~~~ connections ~~~~~~~~~~~~~~~
\draw[->]   (IN) -- (A);
\draw       (A)  |- (P);
\draw       (A)  |- (K);
\draw       (K)  -- (S);
\draw       (S)  -- ++(1.5,0) |- (O.210) node[shift=(220:.3)] {$+$};
\draw       (P)  -- ++(3.0,0) |- (O.150) node[shift=(140:.3)] {$+$};
\draw[->]   (O)  -- (OUT);

\end{tikzpicture}
\end{document}

3. Document using said drawing

There are many ways to use Tikz-diagrams in your main documents class, which, like:

• code it directly into your main.tex
• copy aboves result
• \input aboves result (after some deletions)

The process I'd like to show you here goes like this:

• create the diagram with Tikz, using standalone
• compile as pdf, e.g. as piTikz.pdf (repeat, when changed)
• include it as drawing using package graphicx

\documentclass[10pt,a4paper]{article}
\usepackage{graphicx}
\begin{document}
 This is one way to work with tikzpictures:
\begin{itemize}
  \item create and compile a separate file using standalone class
  \item including said pdf, see figure \ref{pi}
 \end{itemize}
\begin{figure}
  \includegraphics[width=\textwidth]{piTikz}
  \caption{Some PI signal processing}\label{pi}
 \end{figure}
\end{document}