The 1-wire network is the fundamental force behind the WEL.  In its most basic form, the 1-wire network is a simple pair of twisted wires.  One wire in the pair is used to carry a ground reference, and the other is used as a combined power and data bus.  1-Wire devices are just hooked to this bus, and the WEL is able to locate them and assign them unique functions.

Most 1-wire devices don't need any more power than what's provided by the 1-wire bus.  However, when you add additional hardware, like a humidity sensor, some additional power may be required.  For that reason, the WEL's bus also provides a third wire for this additional voltage supply. 

For consistency, the WEL has adopted a color coding system, which makes wiring easier.  The color code is as follows:
 

1-Wire Ground	BLACK
1-Wire Bus	YELLOW
Aux. Power	RED

All products from OurCoolHouse.com have 1-wire terminals identified as Blk, Yel & Red (or B, Y & R)

Likewise, the pre-twisted bus wire uses this same color code.  It's then a simple matter to connect Black-Black, Yellow-Yellow & Red-Red.
 

Here is a picture of a minimal 1-wire bus connection, installed on a WEL Rev3.2 board..  The 1-Wire bus terminals are opposite to the power input terminals.  Ground is at the end, followed by the bus and then the aux. power. Since we typically use solid copper wire (rather than stranded) you also need to be careful when putting more than one wire into a screw terminal.  Unless you tighten the terminal down hard, the wires can move slightly during final installation and cause an intermittent connection.  This is the most common reason for bus problems.

The Web Energy Logger is an Internet Appliance that monitors a 1-wire sensor network, and posts live data to a web site for display and analysis. The WEL was designed for people interested in monitoring the energy distribution of their own homes or businesses. For more background, visit the WEL homepage. ©2008 Phil Malone - - www.OurCoolHouse.com