how to change direction of arrow tikz

Question

How to change the arrow pointing direction, in this case to the right with tikz library.

I have following code,

\documentclass{article}

\usepackage{filecontents}
\usepackage{tikz}
\usetikzlibrary{positioning,fit,calc,arrows,arrows.meta}
\tikzset{block/.style={draw,thick,text width=2cm,minimum height=1cm,align=center},
         line/.style={-latex}
}

\begin{document}

\begin{figure}
\begin{center}
\begin{tikzpicture}[>=stealth]
  %coordinates
  \coordinate (orig)   at (0,0);
  \coordinate (LLD)    at (4,0);
  \coordinate (AroneA) at (-7/2,11/2);
  \coordinate (ArtwoA) at (-7/2,5);
  \coordinate (ArthrA) at (-1/2,9/2);
  \coordinate (LLA)    at (1,4);
  \coordinate (LLB)    at (5,4);
  \coordinate (LLC)    at (9,4);
  \coordinate (AroneC) at (26/2,11/2);
  \coordinate (ArtwoC) at (26/2,5);
  \coordinate (ArthrC) at (25/2,9/2);
  \coordinate (conCBD) at (25/2,10/2);
  \coordinate (conCB)  at (25/2,6/2);
  \coordinate (coCBD)  at (11,6);


  %nodes
  \node[draw, minimum width=2cm, minimum height=2cm, anchor=south west, text width=2cm, align=center] (A) at (LLA) {A};
  \node[draw, minimum width=2cm, minimum height=2cm, anchor=south west, text width=2cm, align=center] (B) at (LLB) {B};
  \node[draw, minimum width=3cm, minimum height=2cm, anchor=south west, text width=2cm, align=center] (C) at (LLC) {C};


  %edges
  \draw[->] (AroneA) -- node[above]{\textit{x}} ($(A.180) + (0,1/2)$);
  \draw[->] (ArtwoA) -- node[above]{\textit{y}} (A.182);

  \draw[->] (A.0) -- node[above] {$x_d$} (B.180);
  \draw[->] (B.0) -- node[above] {$y_d$} (C.180);

  \draw[->] (C.0) -- node[above, pos=0.4]{Y} (ArtwoC);

  \path[fill] (conCBD) circle[radius=1pt];
  \path[-{Straight Barb[angle'=60,scale=4]}] (conCBD) -- (conCB) -| ($(B.180) + (-1,-0.6)$) -| ($(B.180) + (-0.1,-0.8)$);

\end{tikzpicture}

\end{center}

\end{figure}

\end{document}

Answer 1

Relative positioning is a very nice feature of tikz. Absolute positioning can be quite hard and more prone to errors (observe your horizontal lines below x and y in your image). This kind of diagrams in general is best drawn using relative positioning or a matrix of nodes. For the reversed arrow, I used \draw [<-] (B.210) -| ++(-.6,-1) -| ([xshift=.5cm] C.east) node[above]{$Y$};.

\documentclass{article}    
\usepackage{filecontents}
\usepackage{tikz}
\usetikzlibrary{positioning,fit,calc,arrows,arrows.meta}
\begin{document}

\begin{figure}
\centering
\begin{tikzpicture}[>=stealth,blk/.style={draw, minimum width=2cm, minimum height=2cm}]

\node (y) {$y$};
\node (x) [above=2pt of y]{$x$};
\node (A) [right=of y,blk]{A};
\node (B) [right=of A,blk]{B};
\node (C) [right=of B,blk,minimum width=3cm]{C};

\draw [->] (y)--(A);
\draw [->] (x)--(A.west|-x);
\draw [->] (A)--node[above]{$x_d$}(B);
\draw [->] (B)--node[above]{$y_d$}(C);
\draw [->] (C.east)--++(1,0);    
\draw [<-] (B.210) -| ++(-.6,-1) -| ([xshift=.5cm]C.east)node[above]{$Y$};

\end{tikzpicture}
\end{figure}

\end{document}