Ask the Expert
<< Go back to Ask the Expert
INDEX
Updated October 6, 2006 06:00 PST
You've got questions, we've got answers.
This installment, Grant Sullivan from Leviton Manufacturing,
Home Control Products, takes the reins.
1. Is Z-Wave two-way?
Most Z-Wave products are two way, allowing wall-mounted
controllers and software to be aware of whether lights are
on/off or dimmed throughout a network. We can even report
the lighting intensity level for an individual device. This
means when you push a button on a wall-mounted zone controller,
you will get an indication on the controller when the lights
(often in other areas of the home) have turned on or off,
accurately. The alternative is to blindly send a command
from a controller and trusting that the system performed
as expected.
2. Is there a need for a central controller in a Z-Wave
lighting system?
No. That's a major value of a mesh network. Other lighting
control systems that have been on the market for a while
have relied on a centralized lighting cabinet. All lighting
circuits require wires that lead back to this cabinet, and
all control functions (scenes, zones, intensity) are controlled
inside this cabinet. User use wall-mounted switches, dimmer
and controllers to operate the system. But, everything is
hard wired back to one control cabinet.
Z-Wave eliminates the centralized cabinet requirement,
thus dramatically lowering the costs, by allowing each device
to become an intelligent transceiver: sending and receiving
command information wirelessly. Putting all these individual
intelligent devices into a home makes the entire system
more reliable, efficient and scaleable. It also allows the
products to be used in retrofit and new home construction
with equal results.
3. How does Z-Wave compare to X10?
X10 is a lot like learning BASIC. Everyone has used it,
and once they learn it, they have learned not to use it
again. Seriously though, X10 is ideal for simple applications
such as controlling a lamp across the room. It runs into
reliability problems when the installer begins thinking
of X10 in a whole-house installation. The more X10 products
that are installed in a home, the less reliable the system
becomes. Z-Wave is the opposite: More Z-Wave components
installed in a home increases the reliability of the entire
system.
4. Why use 900-MHz range, rather than 2.4 GHz?
Less traffic and better performance. If this question were
asked 5 years ago, it would be more valid because wireless
telephones took much of the space at the 900-MHz spectrum.
However, many of those wireless devices are migrating into
the 2.4-GHz space, along with Wi-Fi, video, security cameras,
wireless audio, and more. Another important fact is that
900 MHz allows a signal to be stronger and transmit through
longer distances (including walls, floors, and ceilings)
with more power than a 2.4-GHz signal.
Grant W. Sullivan is the product marketing manager for
Leviton Manufacturing, Home Automation Products.
