Add label to right-angled connector -

Question

I'm try to add a label to a right-angled connector in a TikZ figure. Below is the code I'm using:

\begin{tikzpicture}[every node/.style={minimum height={1.5cm},thick,align=center},node distance=2.5cm, auto]
\node[draw] (CC) {CC};
\node[draw, right= of CC] (PC) {PC};
\node[draw, dashed, below= of CC] (AP) {DP};
\node[draw, dashed, below= of AP] (SP) {SP};
\node[draw, below = of SP] (BD) {BD};
\draw[->] (CC) to node {DM} (AP);
\draw[->] (AP.west) |- ($(AP.west) - (2.0,0)$) |- (BD.west);
\draw[->] (PC) |- (SP);
\draw[->] (AP) to node {SPa} (SP);
\draw[->] (SP) to node {Al} (BD);
\end{tikzpicture}

This is what is being output plus the label I would like to put is marked in red.

How could this be done? I've tried putting in the usual {text} in \draw[->] (AP.west) |- ($(AP.west) - (2.0,0)$) |- (BD.west); but I'm either getting an error or the label is being misplaced.

Thanks in advance!

Answer 1

You can use a node in the corresponding path:

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{positioning,calc}

\begin{document}

\begin{tikzpicture}[every node/.style={minimum height={1.5cm},thick,align=center},node distance=2.5cm, auto]
\node[draw] (CC) {CC};
\node[draw, right= of CC] (PC) {PC};
\node[draw, dashed, below= of CC] (AP) {DP};
\node[draw, dashed, below= of AP] (SP) {SP};
\node[draw, below = of SP] (BD) {BD};
\draw[->] (CC) to node {DM} (AP);
\draw[->] (AP.west) |- ($(AP.west) - (2.0,0)$) |- node[near start,swap] {Label} (BD.west);
\draw[->] (PC) |- (SP);
\draw[->] (AP) to node {SPa} (SP);
\draw[->] (SP) to node {Al} (BD);
\end{tikzpicture}

\end{document}

Answer 2

For vertical positioning you can use the ($(node a)!x!(node b)$) modifier together with the xshift key.

The corresponding line becomes

\draw[->] (AP.west) -| ([xshift=-2cm]$(AP)!0.5!(BD)$) node[red,left] {Label} |- (BD.west);

This way you don't have to guess how much shift you need to enter.