Re: Need help with PLC noise problems in a Manhattan (New York City) apartment

[nobody@xxxxxxxxxxxx (Dave Houston)]

X-10 has documented that spikes can directly cause some devices to operate.

     http://www.x10.com/support/x10trou.htm#on

Steven Bloom has a 'fix' for certain switches.


http://groups.google.com/group/comp.home.automation/msg/62d41d8a36fef5ea?oe=UTF-8&output=gplain

Some modules are less susceptible than others. I had problems with a
screw-in module (the older dimmable one) turning off when I turned a
flurescent light off. I replaced the screw-in module with an LM14A and npo
longer have the problem.

However, it's unlikely that such switching transients would show up as
"120kHz Activity" on his TesterLinc.

"tparent" <tparent@xxxxxxxxxx> wrote:

>If you are fully insulated from "external" noise or unsollicited X10
>(neightbour RF or PLC), I discovered in my case that most of my noise
>problem are coming from fluorescent bulb.
>
>Like already explained, I'm talking about interference meaning that one
>specific X10 command become an unpredictable result (issuing D10 ON,
>result is D10 ON and D12 OFF at the same time). Sometime X10 device are
>triggered without any issued X10 command (often lamp module).
>
>These kind of strange behaviour is not detectable by computer interface
>or dumpable through PC software.
>
>Most of the time, "uncontrollable device" are basic X10 type (LM465,
>AM..), but it's not systematic (less often Smarthome or ADS could be
>hit).
>
>After hours trying to guess what really happens with a digital
>oscilloscope, I have the following feeling (I'm not a pro, just an
>enthusiast) :
>- Fluorescent bulb generate at zero crossing a current spike around
>0.3V.
>- This spike doesn't seems to be 120khz but are not filtered by LM465
>electronic (as a consequence, spike is 'readable" on chip pin 1. In
>specific condition (were the signal parasite match with X10 command,
>the original command is tampered by fluorescent bulb spike".
>-by the fact that spike are "low current", they are unable to be spread
>on whole installation (attenuation will kill il before reaching
>distribution panel).
>
>On the basis of my test, I believe that basic X10 module doesn't
>"stricto sensu" follow X10 protocol for the following reasons :
>- they are not waiting the expected delay with 120khz on the line to
>consider the signal valid (spike is enough to be considered valid).
>-they are not matching the first and second copy of the X10 command
>(only one is analysed and interpreted). In one of my room, two module
>on the same address are triggered with a delay between the two. My
>explanation is, the first one is on "good line" the second on a line
>which require "signal repeater" to be listenable. First is directly
>triggered on the first copy of X10, second is triggered by the signal
>repeater amplified command with small delay.
>
>It's very difficult to provide solution (excluding removing all
>Fluorescent bulb).
>Just few good practice :
>- Plug your "X10 sending" device on a dedicate line directly wired to
>the distribution panel.
>- If it happens with one fluorescent bulb brand, try another one. On
>basis of scope analysis, they are all noisy but some are producing
>twice time bigger interference than others.
>- replace "basic X10" by more reliable.
>
>Hope it helps
>(happy to be back "on the X10 battlefield",discovered that my new ISP
>is not forwarding my replies on usenet since 6 month).
>
>Thierry
>
>Dave Houston wrote:
>> Any RF system is likely to be problematic in a densely inhabited urban
>> environment.
>>
>> My mystery signal disappeared after being here 24/7 for about a week.
>>
>> "Robert Green" <ROBERT_GREEN1963@xxxxxxxxx> wrote:
>>
>> >If I were in your shoes, I would look to an RF solution that didn't care a
>> >whit how dirty the powerline was.  We've recently seen a "2 apartments
>> >combined" scenario stump our resident X-10 expert, who was armed with both
>> >an oscilloscope and a million man-ours of X-10 experience.  That doesn't
>> >bode well for you.