What is X10 home automation, how does X10 work, and what are the limitations of X10?
Though now outdated, some companies still promote X10 for home
automation applications on the Internet. As part of your Internet survey of home
automation technologies, you may want to know what X10 is, how it works, and why newer
more advanced wired and wireless home automation systems have since been developed.
|What is X10 home automation?
- X10 is an early home automation technology that was developed by Pico Electronics of
Glenrothes in Scotland back in 1975.
- X10 became popular because it used to be one of the few home automation that could be
easily retro-fitted into existing homes without installing additional cabling, and because
of it's entry-level quality and pricing.
- X10 is an open protocol for communication among home automation devices that primarily
uses mains wiring for signalling and control, where the signals are superimposed upon the
sinusoidal mains waveform. A supplemental radio based X10 protocol is also defined. See
below for more details.
- Many X10 home automation devices plug into a power point, and then you plug your lights
or appliances to be controlled plug into the X10 device. Built-in X10 wall switches and
ceiling fixture controllers are also available.
- An X10 interface used to be supported on the now obsolete Clipsal
Home Minder, but modern home automation systems now have little need to
provide any X10 support because newer more advanced alternatives to X10 are available.
- More recent and more advanced home automation technology now provides
faster, more reliable and secure communication and control than X10 equipment. Once such
up-to-date example is the new range of Clipsal C-Bus Wireless home
automation products, which also includes classy glass
Saturn style C-Bus wireless home automation wall switches.
||Clipsal C-Bus Wireless home automation
|How does X10 home automation work?
- X10 home automation uses your existing mains wiring to communicate digital data between
X10 devices. Bursts of data encoded on a 120 kHz carrier are transmitted during the
zero crossings of the 50/60 Hz AC voltage waveform, with only one digital bit being
transmitted at each zero crossing.
- X10 digital data comprises an address and a command sent from an X10 controller to an
X10 controlled device. More advanced X10 controllers may also query the on/off or level
status of each other using the X10 protocol.
- Special measures need to be taken to help X10 signals pass from one phase to another, or
across split phase systems, when this is required. This usually involves using coupling
capacitors or an active X10 repeater, or X10 signal amplifiers and a coupling capacitor.
- Care also needs to be taken to prevent X10 communications from leaking from one house to
another along the mains wiring that extends out into the street, and is common among
homes. To help prevent this special X10 inductive filters to attenuate X10 signals as they
pass out from your home on the incoming mains supply feeds.
- X10 wired or wireless protocol packets consist of a four bit (one of 16) "house
code" followed by one or more four bit "unit codes" (that in combination
with the house code create 16*16=256 possible addresses within the same residence) and
then a four bit "command". Different house codes often need to be used within
the same home to generate enough distinct X10 addresses, and so they are usually not
available to help distinguish one X10 house installation from a neighbouring one.
|What are the limitations
of X10 home automation?
- X10 communications are slow. Transmitting a device address and command via X10 takes
approximately 0.75 seconds. This can be problematic in 2 way switching applications where
two parties may switch a common set of lights back on/off unintentially.
- If more than one X10 signal is generated at the same time, they will interfere with each
other and may prevent each other from being correctly received or acted upon. X10 signals
need to be generated one at a time in order to work reliably, which can be problematic
from time to time in a home with more than one occupant.
- Home owners may experience load-related unreliable X10 communications, where the
reliability decreases and increases as particular 240V loads such as ovens or hair dryers
are switched on or off.
- The operation of televisions or wireless equipment may result in spurious X10 on/off
signals, and if you install EMI noise filters to reduce such interferrence they may also
attenuate X10 signals if they are not specifically designed for X10 installations.
- The power supplies in some computerised electronic appliances (e.g. computers, TVs etc)
may include EMI suppressing capacitors (to help them comply with EMI regulations) that
also unintentionally attenuate X10 signals. Special X10 devices may need to installed to
selectively isolate X10 from such power supplies (but not other parts of your home
electrical wiring that may have X10 devices connected) to prevent this unwanted
attenuation of X10 signals. Discovering and isolating the causes of this type of
disruption to the operation of an X10 home automation system operation can be time
consuming and frustrating.
- X10 signals can be attenuated by Earth Leakage Detectors (otherwise known as Saftey
Switches, or RCDs) to the point where X10 communications become unreliable.
|Contact a Clever Home
Engineer now about home automation that does not use X10 devices.
- Clever Home does not recommend X10 devices for home automation
- Clever Home chooses not to supply or support any X10 devices.