Other products to improve reliability
Installing a SignaLinc Repeater is one of the best things you can do to increase the
reliability of your home automation system, however in some cases, you may need to
take additional steps to help ensure that your system operates reliably.
Since PLC signals go everywhere in the home, some electrical devices will have more
of an effect on the signal strength than other devices. PLC signals are like water
pressure in pipes, it actually goes everywhere it can, not just to the receiving module.
In the last 20 years, an explosion of electrical devices has invaded our homes.
Computers, video gear, and fancy high-end electronics are more present than in years
past. The more complicated the electrical power supply is in a device, the more likely
it is to absorb PLC signals. Engineers who design power supplies build in traps to
filter out and kill electrical noise. Unfortunately, the PLC signals looks like electrical
noise to these devices. The result is that a large percent of the transmitted signal is
lost to these devices leaving less for the receivers. The most common sources of
signal loss are:
• Televisions
• Computer systems
• Audio/Video gear
• Computer UPS's and power strips
• Power supplies for laptops and cell phones
Testing for the problem is simple. If a device is suspected of
causing signal absorption, unplug the device and then re-
transmit the signal. It is very important that the device is
unplugged and not just turned off! If the controlled product
begins working after the appliance is unplugged, then a filter
will be needed on that device to keep PLC signals from being
absorbed and raise the signal strength of the entire home.
Smarthome has many filters that will fix the problem. An
average home will need between three and five filters. If you
are in the business of installing automation systems and not in
the ‘call-back’ business, include some of these in your bid as
part of the standard package.
How Does a Signal Bridge Compare to Coupler-Repeater?
To determine just how well SignaLinc Repeater works in the home, check the signal
strength on the receiving phase and transmission phase using a powerline signal
analyzer both before and after installing the SignaLinc. The table below illustrates the
differences achievable in a home with no signal coupler, a passive SignaLinc, and a
SignaLinc Repeater.
All values in volts
Generally, most modules will respond to signals that are .100 volts or greater.
Smarthome Design products will need much less (at least .050 volts), but can
sometimes pick out signals below .015 volts (15 mV). Professional installers want at
least .250 volts for a reliable system.
For this test, a special signal generator was calibrated to output a 1.0-volt signal. With
no signal coupler
installed it is easy to notice that half the outlets (on the same
phase as the transmitter) have pretty good signal strength (.68 to .44 volts). However,
outlets on the opposite line (phase “B”) are extremely weak and would very likely
experience intermittent operation. Most homes have two lines of 120-volts coming in
from the utility company. Each line or "phase" services half the electrical devices in
the home.
When a
non-amplifying SignaLinc
is attached, the signal becomes more evenly
distributed. Most of the outlets and switches on the "B" phase now have a much
stronger signal. The signal strength on phase "A" actually decreased a little as the
signal is more even distributed between phases. Notice that the home theater lighting
circuit is still way too low for reliable operation. A closer examination of this circuit
reveals the owner has installed multiple 2-way switches and keypad transmitters,
which will load down or absorb the PLC signal.
When a
SignaLinc Repeater
is installed (in place of the passive SignaLinc), all the
circuits now have excellent signal strength. The signals on the originating phases
show a good increase (16% to 47%). The circuits on the opposite "B" phase all
increased considerable. The home theater lighting circuit is still lower than the other
phases. If additional 2-way modules are later installed, the signal strength may fall to
unreliable levels. On this circuit, the owner should install a BoosterLinc™ (see page 5).
4
Smarthome’s BoosterLinc
™
can solve localized problems
SignaLinc Repeater is ideal for improving the home
automation signal strength throughout all the
outlets in a home. But, as the PLC signals travel
down a circuit and away from the repeater, it will
weaken by the same factors listed above.
Additionally, the signal will get weaker as it passes
installed PLC transmitters. Each PLC transmitter
contains a tuned circuit that when it's not sending
signals it's absorbing them! In addition to plug-in
transmitters, LampLinc™ 2-Way, SwitchLincs™ 2-
Ways, ToggleLinc™ 2-Ways, ApplianceLinc™ 2-Ways,
KeypadLincs™, or any module with 2-way abilities will load down the available
signal. With so many transmitters installed, the signal is loaded down to a point
where some modules will be unable to receive a signal. Installing multiple 2-way
devices on one branch circuit may necessitate the use of local amplifier like
Smarthome's BoosterLinc.
5
Outlet
Phase
No signal
coupler
Passive
SignaLinc
SignaLinc
Repeater
Improvement
over none
Same outlet as transmitter
A
1.000
1.100
1.160
16%
Family room
A
.680
.500
.913
34%
Office lights
A
.560
.430
.825
47%
Master bedroom
A
.440
.340
.595
35%
Laundry room
B
.093
.380
1.50
1513%
Patio
B
.038
.240
.968
2447%
Garage
B
.049
.220
.795
1522%
Home Theater outlets
B
.040
.240
1.10
2650%
Home Theater lighting
B
.012
.013
.105
775%
#1626 FilterLinc
TM
Plug-IIn Filter
#4827 BoosterLinc
TM
Plug-IIn Amplifier
